EPA/600/8-87/020
August 1987
Analytical Methods Manual for the
Direct/Delayed Response Project Soil Survey
by
K.A. Cappo, L.J. Blume, G.A. Raab, J.K. Bartz, and J.L. Engels
A Contribution to the
National Acid Precipitation Assessment Program
U.S. Environmental Protection Agency
Region 5, Library (5PL-16)
230 S. Dearborn Street, Boom 167-0
$hicagoA £1*
U.S. Environmenlal Protection Agency
Office of Modeling, Monitoring Systems, and Quality Assurance
Office of Ecological Processes and Effects Research
Office of Research and Development
Washington, D.C. 20460
Environmental Monitoring Systems Laboratory, Las Vegas, Nevada 89193
Environmental Research Laboratory, Corvallis, Oregon 97333
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Notice
The information in this document has been funded wholly or in part by the U.S. Environmental
Protection Agency under Contract Number 68-03-3249 to Lockheed Engineering and Management
Services Company, Inc. It has been subject to the Agency's peer and administrative review, and
it has been approved for publication as an Agency document.
Mention of trade names or commercial products is for illustration purposes and does not
constitute endorsement or recommendation for use.
This document is one volume of a set which fully describes the Direct/Delayed Response
Project, Northeast and Southeast soil surveys. The complete document set includes the major data
report, quality assurance plan, analytical methods manual, field operations reports, and quality
assurance reports. Similar sets are being produced for each Aquatic Effects Research Program
component project. Colored covers, artwork, and the use of the project name in the document title
serve to identify each companion document. The proper citation of this document remains:
Cappo, K. A., L J. Blume, G. A. Raab, J. K. Bartz, and J. L. Engels. 1987. Analytical Methods
Manual for Direct/Delayed Response Project Soil Survey. EPA/600/8-87/020. U.S. Environmen-
tal Protection Agency, Office of Research and Development, Las Vegas, Nevada. 318 pp.
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Abstract
The U.S. Environmental Protection Agency, in conjunction with the National Acid Precipitation
Assessment Program, has designed and implemented a research program to predict the long-term
response of watersheds and surface waters in the United States to acidic deposition. On the
basis of this research, each watershed system studied will be classified according to the time
scale in which it will reach an acidic steady state, assuming current levels of acidic deposition.
The U.S. Environmental Protection Agency requires that data collection activities be based on
a program which ensures that the resulting data are of known quality and are suitable for the
purpose for which they are intended. In addition, it is necessary that the data obtained be
consistent and comparable throughout the survey. For these reasons, the same detailed analytical
methodology must be available to and must be used by all analysts participating in the study.
This manual specifies the analytical methods and internal quality control used to process and
analyze samples for the Direct/Delayed Response Project Soil Survey. The determinations and
methods described are the following:
1. Air-dry moisture content
2. Particle size analysis
3. pH (in deionized water)
0.01 M CaCI2 0.002 M CaCI2
4. Total C, Total N, Total S
5. Inorganic C
6. Cation exchange capacity (using
NH4OAc and NH4CI saturating
solutions)
7. Exchangeable Ca, Mg. and Na
in NH4OAc, NH4CI, and CaCI2
8. Exchangeable K in NH4OAc,
NH4CI, and CaCI2
9. Fe exchangeable in CaCI2;
extractable in pyro-
phosphate, acid-oxalate
and citrate-dithionite
10. Al extractable in pyro-
phosphate, acid-oxalate,
and citrate-dithionite
11. Al exchangeable in CaCI2
and KCI
12. Nitrate (NO/) water
extractable
Gravimetric
Sieve/pipet/gravimetric
Combination electrode/millivoltmeter
Elemental analyzer
Coulometric
Autotitration or flow injection
analyzer
Flame atomic absorption spectroscopy,
inductively coupled plasma atomic emission
spectroscopy (or flame atomic emission
spectroscopy for Na only)
Flame atomic absorption spectroscopy
or flame atomic emission spectroscopy
Flame atomic absorption spectroscopy
or inductively coupled plasma atomic
emission spectroscopy
Flame atomic absorption spectroscopy
or inductively coupled plasma atomic
emission spectroscopy
Inductively coupled plasma atomic
emission spectroscopy
Ion chromatography
in
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Abstract (Continued)
13. Sulfate (SO^) Water Ion chromatography
extractable, phosphate
extractable, and sulfate
adsorption 6-point isotherm
14. Exchangeable acidity in BaCI2- Titrimetric
Triethanolamine and KCI
saturating solutions
15. Specific surface Gravimetric
This report was submitted in partial fulfillment of Contract Number 68-03-3249 by Lockheed
Engineering and Management Services Company, Inc., under the sponsorship of the U.S.
Environmental Protection Agency.
IV
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Date: 12/86
Page 1 of 10
Contents
Section Page Revision
1 Introduction 1 of 9 2
1.1 Project Overview 1 of 9 2
1.2 Field Activities 3 of 9 2
1.3 Laboratory Activities 7 of 9 2
1.4 Quality Assurance/Quality Control 9 of 9 2
1.5 Data Handling 9 of 9 2
1.6 References 9 of 9 2
2 Laboratory Operations 1 of 18 2
2.1 Preparation Laboratory Procedures 1 of 18 2
2.2 Sample Receipt and Handling at the Analytical Laboratory 1 of 18 2
2.3 Cleaning Procedures for the Analytical Laboratory 2 of 18 2
2.3.1 Plasticware to be used for pH, Acidity, Alkalinity,
Cation Exchange Capacity (CEC) Titrations,
and Anion Determinations 2 of 18 2
2.3.2 Other Plasticware 2 of 18 2
2.3.3 Glassware 2 of 18 2
2.4 Procedure for Washing Filter Pulp 3 of 18 2
2.5 Sample Analyses by the Analytical Laboratory 3 of 18 2
2.6 Internal Quality Control Within Each Analytical Method 3 of 18 2
2.6.1 Initial Calibration 3 of 18 2
2.6.2 Calibration Blank 12 of 18 2
2.6.3 Quality Control Calibration Samples (QCCS) 12 of 18 2
2.6.4 Detection Limit QC Samples 13 of 18 2
2.6.5 Reagent Blank 13 of 18 2
2.6.6 Preliminary Sample Analysis 14 of 18 2
2.6.7 Matrix Spike Analysis 14 of 18 2
2.6.8 Duplicate Sample Analysis 14 of 18 2
2.6.9 Ion Chromatography Resolution Test 15 of 18 2
2.6.10 Continuing Sample Analysis 16 of 18 2
2.7 Instrumental Detection Limits 16 of 18 2
2.8 Reagent Blank Correction for Spectrometric and Ion
Chromatographic Procedures 16 of 18 2
2.9 Data Reporting 16 of 18 2
2.10 Sample Handling for Mineralogical Analyses 16 of 18 2
2.11 Laboratory Procedures for Mineralogical Analyses 17 of 18 2
2.12 References 17 of 18 2
3 Moisture Content 1 of 2 2
3.1 Scope and Application 1 of 2 2
3.2 Summary jf Method 1 of 2 2
3.3 Interferences 1 of 2 2
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Contents (Continued)
Section Page fJevfsfon
3.4 Safety 1 of 2 2
3.5 Apparatus and Equipment 1 of 2 2
3.6 Reagents and Consumable Materials 1 of 2 2
3.7 Sample Collection, Preservation, and Storage 1 of 2 2
3.8 Calibration and Standardization 1 of 2 2
3.9 Quality Control 1 of 2 2
3.10 Procedure 1 of 2 2
3.11 Calculations 2 of 2 2
3.12 Precision and Accuracy 2 of 2 2
3.13 References 2 of 2 2
4 Particle-Size Analysis 1 of 6 2
4.1 Scope and Application 1 of 6 2
4.2 Summary of Method , 1 of 6 2
4.3 Interferences 1 of 6 2
4.4 Safety 1 of 6 2
4.5 Apparatus and Equipment 1 of 6 2
4.6 Reagents and Consumable Materials 2 of 6 2
4.7 Sample Collection, Preservation, and Storage 2 of 6 2
4.8 Calibration and Standardization 2 of 6 2
4.9 Quality Control 2 of 6 2
4.10 Procedure 2 of 6 2
4.10.1 Removing Organic Matter 2 of 6 2
4.10.2 Removing Dissolved Mineral and Organic Components ... 3 of 6 2
4.10.3 Dispersing the Sample 3 of 6 2
4.10.4 Separating Sand from Silt and Clay 3 of 6 2
4.10.5 Pipetting 3 of 6 2
4.10.6 Sieving and Weighing the Sand Fractions 5 of 6 2
4.11 Calculations 6 of 6 2
4.12 Precision and Accuracy 6 of 6 2
4.13 References 6 of 6 2
5 Specific-Surface Determination 1 of 3 2
5.1 Scope and Application 1 of 3 2
5.2 Summary of Method 1 of 3 2
5.3 Interference 1 of 3 2
5.4 Safety 1 of 3 2
5.5 Apparatus and Equipment 1 of 3 2
5.6 Reagents and Consumable Materials 1 of 3 2
5.7 Sample Collection, Preservation, and Storage 2 of 3 2
5.8 Standardization and Calibration 2 of 3 2
5.9 Quality Control 2 of 3 2
5.10 Procedure 2 of 3 2
5.11 Calculations 3 of 3 2
vi
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Contents (Continued)
Section Page Revision
5.12 Precision and Accuracy 3 of 3 2
5.13 References 3 of 3 2
6 pH Determination 1 of 4 2
6.1 Scope and Application 1 of 4 2
6.2 Summary of Method 1 of 4 2
6.3 Interferences 1 of 4 2
6.4 Safety 1 of 4 2
6.5 Apparatus and Equipment 1 of 4 2
6.6 Reagents and Consumable Materials 2 of 4 2
6.7 Sample Collection, Preservation, and Storage 2 of 4 2
6.8 Calibration and Standardization 2 of 4 2
6.9 Quality Control 3 of 4 2
6.9.1 Quality Control Calibration Sample 3 of 4 2
6.9.2 Blank Samples 3 of 4 2
6.9.3 Replicate Samples 3 of 4 2
6.10 Procedure 3 of 4 2
6.11 Calculations 5 of 4 2
6.12 Precision and Accuracy 5 of 4 2
6.13 References 5 of 4 2
7 Cation Exchange Capacity 1 of 10 2
7.1 Scope and Application 1 of 10 2
7.2 Summary of Method 1 of 10 2
7.3 Interferences 1 of 10 2
7.4 Safety 1 of 10 2
7.5 Apparatus and Equipment 1 of 10 2
7.5.1 Apparatus for Saturation Procedure 2 of 10 2
7.5.2 Apparatus for Automated Distilled-Titration Analysis 2 of 10 2
7.5.3 Apparatus for Manual Distillation/Automated
Titration Analysis 2 of 10 2
7.5.4 Apparatus for Ammonium Displacement-Flow
Injection Analysis 2 of 10 2
7.6 Reagents and Consumable Materials 2 of 10 2
7.6.1 Reagents for Saturation Procedure 2 of 10 2
7.6.2 Reagents and Consumable Materials for Automated
Distillation-Titration Analysis 4 of 10 2
7.6.3 Reagents and Consumable Materials for Manual
Distillation-Automatic Titration Analysis 4 of 10 2
7.6.4 Reagents and Consumable Materials for Ammonium
Displacement-Flow Injection Analysis 5 of 10 2
7.7 Sample Collection, Preservation, and Storage 5 of 10 2
7.8 Calibration and Standardization 5 of 10 2
7.9 Quality Control 6 of 10 2
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Contents (Continued)
Section Page Revision
7.10 Procedure 6 of 10 2
7.10.1 Saturation Procedure 6 of 10 2
7.10.2 Analytical Procedure using Automated
Distillation-Titration 6 of 10 2
7.10.3 Analytical Procedure using Manual Distillation-
Automated Titration 6 of 10 2
7.10.4 Analytical Procedure using Ammonium Displacement-
Flow Injection Analysis 7 of 10 2
7.10.5 NH4+ Cl Saturation Procedure 9 of 10 2
7.11 Calculations 9 of 10 2
7.11.1 Results for either Distillation-Titration Analytical
Procedure (Section 7.10.2 or 7.10.3) 9 of 10 2
7.11.2 Results from Ammonium Displacement-Flow Injection
Analysis Procedure (Section 7.10.4) 9 of 10 2
7.12 Precision and Accuracy 9 of 10 2
7.13 References 9 of 10 2
8 Exchangeable Basic Cations 1 of 15 2
8.1 Scope and Application 1 of 15 2
8.2 Summary of Method 1 of 15 2
8.2.1 Atomic Absorption (for Ca2+, Mg2+, K+, and Na+) 2 of 15 2
8.2.2 Inductively Coupled Plasma (for Ca2+, Mg2+, and Na+) .... 2 of 15 2
8.2.3 Flame Photometry (for K+ and Na+) 3 of 15 2
8.3 Interferences 3 of 15 2
8.3.1 Spectral Interferences 3 of 15 2
8.3.2 Chemical Interferences 4 of 15 2
8.3.3 Physical Interferences 4 of 15 2
8.3.4 Matrix Effects 5 of 15 2
8.4 Safety 5 of 15 2
8.5 Apparatus and Equipment 5 of 15 2
8.5.1 Determinations by Atomic Absorption 5 of 15 2
8.5.2 Determination by Inductively Coupled Plasma 5 of 15 2
8.5.3 Determination by Flame Photometry 5 of 15 2
8.6 Reagents and Consumable Materials 6 of 15 2
8.6.1 Determination by Atomic Absorption 6 of 15 2
8.6.2 Determination by Inductively Coupled Plasma 6 of 15 2
8.6.3 Determination by Flame Photometry 7 of 15 2
8.7 Sample Handling, Preservation, and Storage 7 of 15 2
8.8 Calibration and Standardization 8 of 15 2
8.9 Quality Control 9 of 15 2
8.10 Procedure 9 of 15 2
8.10.1 Procedure for Determination by Atomic Absorption 9 of 15 2
8.10.2 Procedure for Determination by Inductively
Coupled Plasma 12 of 15 2
8.10.3 Procedure for Determination by Flame Photometry 12 of 15 2
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Contents (Continued)
Section Page Revision
8.11 Calculations 13 of 15 2
8.11.1 Solution Concentrations 13 of 15 2
8.11.2 Dilutions 13 of 15 2
8.11.3 Flame Photometry 13 of 15 2
8.11.4 Atomic Absorption or Inductively Coupled Plasma 13 of 15 2
8.12 Precision and Accuracy 14 of 15 2
8.12.1 Determination by Atomic Absorption 14 of 15 2
8.12.2 Determination by Inductively Coupled Plasma 14 of 15 2
8.12.3 Determination by Flame Photometry 14 of 15 2
8.13 References 14 of 15 2
9 Exchangeable Acidity 1 of 7 2
9.1 Scope and Application 1 of 7 2
9.2 Summary of Method 1 of 7 2
9.3 Interferences 1 of 7 2
9.4 Safety 1 of 7 2
9.5 Apparatus and Equipment 1 of 7 2
9.5.1 General 2 of 7 2
9.5.2 Instrumentation for Determination by ICP 2 of 7 2
9.6 Reagents and Consumable Materials 2 of 7 2
9.7 Sample Collection, Preservation, and Storage 3 of 7 2
9.8 Calibration and Standardization , . 3 of 7 2
9.8.1 Titration 3 of 7 2
9.8.2 Determination of Aluminum 3 of 7 2
9.8.3 Method of Standard Additions for Determination
of Aluminum 3 of 7 2
9.9 Quality Control 4 of 7 2
9.10 Procedure 4 of 7 2
9.10.1 Barium Chloride (BaCI2-TEA) Method 4 of 7 2
9.10.2 Potassium Chloride (KCL) Method 5 of 7 2
9.10.3 Determination of Aluminum 6 of 7 2
9.11 Calculations 7 of 7 2
9.12 Precision and Accuracy 7 of 7 2
9.13 References 7 of 7 2
10 Lime and Aluminum Potential 1 of 7 2
10.1 Scope and Application 1 of 7 2
10.2 Summary of Method 1 of 7 2
10.3 Interferences 1 of 7 2
10.4 Safety 1 of 7 2
10.5 Apparatus 2 of 7 2
10.5.1 General 2 of 7 2
10.5.2 Instrumentation for Determination by AA 2 of 7 2
10.5.3 Instrumentation for Determination by ICP 2 of 7 2
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Contents (Continued)
Section Page Revision
10.5.4 Instrumentation for Determination by
Flame Photometery 2 of 7 2
10.6 Reagents and Consumable Materials 2 of 7 2
10.7 Sample Collection, Preservation, and Storage 3 of 7 2
10.8 Calibration and Standardization 3 of 7 2
10.9 Quality Control 4 of 7 2
10.10 Procedure 4 of 7 2
10.10.1 Preparation of Sample Tubes 4 of 7 2
10.10.2 Sample Preparation 4 of 7 2
10.10.3 Extraction 4 of 7 2
10.10.4 Determination of Ca2+, Mg2+, K+, Na+, Fe3+, and AJ3+ 4 of 7 2
10.11 Calculations 6 of 7 2
10.12 Precision and Accuracy 6 of 7 2
10.13 References 7 of 7 2
11 Extractable Iron and Aluminum 1 of 7 2
11.1 Scope and Application 1 of 7 2
11.2 Summary of Method 1 of 7 2
11.3 Interferences 1 of 7 2
11.4 Safety 1 of 7 2
11.5 Apparatus and Equipment 2 of 7 2
11.5.1 General 2 of 7 2
11.5.2 Instrumentation for Detemination by AA 2 of 7 2
11.5.3 Instrumentation for Determination by ICP 2 of 7 2
11.6 Reagents and Consumable Materials 2 of 7 2
11.6.1 Sodium Pyrophosphate Extraction 2 of 7 2
11.6.2 Citrate-Dithionite Extraction 2 of 7 2
11.6.3 Acid-Oxalate Extraction 3 of 7 2
11.6.4 Determination of Fe and Al 3 of 7 2
11.7 Sample Collection, Preservation, and Storage 3 of 7 2
11.8 Calibration and Standardization 3 of 7 2
11.8.1 General 3 of 7 2
11.8.2 Method of Standard Additions for Detemination
of Fe and Al 3 of 7 2
11.9 Quality Control 4 of 7 2
11.10 Procedures 4 of 7 2
11.10.1 Sodium Pyrophosphate 4 of 7 2
11.10.2 Citrate-Dithionite Extraction 4 of 7 2
11.10.3 Acid-Oxalate Extraction 5 of 7 2
11.10.4 Determination of Aluminum 6 of 7 2
11.11 Calculations 7 of 7 2
11.12 Precision and Accuracy 7 of 7 2
11.13 References 7 of 7 2
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Contents (Continued)
Section Page Revision
12 Extractable Sulfate and Nitrate 1 of 8 2
12.1 Scope and Application 1 of 8 2
12.2 Summary of Method 1 of 8 2
12.3 Interferences 1 of 8 2
12.4 Safety 2 of 8 2
12.5 Apparatus and Equipment 2 of 8 2
12.6 Reagents and Consumable Materials 2 of 8 2
12.7 Sample Collection, Preservation, and Storage 3 of 8 2
12.8 Calibration and Standardization 3 of 8 2
12.9 Quality Control 3 of 8 2
12.10 Procedure 4 of 8 2
12.10.1 Extraction of Sulfate 4 of 8 2
12.10.2 Extraction of Sulfate by Sodium Phosphate
(NaH2POJ Solution 4 of 8 2
12.10.3 Determination of Sulfate (SO2\) and Nitrate (NO'g)
by Ion Chromatography 5 of 8 2
12.11 Calculations 7 of 8 2
12.12 Precision and Accuracy 7 of 8 2
12.13 References 7 of 8 2
13 Sulfate-Adsorption Isotherms 1 of 3 2
13.1 Scope and Application 1 of 3 2
13.2 Summary of Method 1 of 3 2
13.3 Interferences 1 of 3 2
13.4 Safety 1 of 3 2
13.5 Apparatus and Equipment 1 of 3 2
13.6 Reagents and Consumable Materials 1 of 3 2
13.7 Sample Collection, Preservation, and Storage 2 of 3 2
13.8 Calibration and Standardization 2 of 3 2
13.9 Quality Control 2 of 3 2
13.10 Procedure 2 of 3 2
13.11 Calculations 2 of 3 2
13.12 Precision and Accuracy 3 of 3 2
13.13 References 3 of 3 2
14 Total Carbon and Total Nitrogen 1 of 6 2
14.1 Scope and Application 1 of 6 2
14.2 Summary of Methods 1 of 6 2
14.3 Interferences 1 of 6 2
14.4 Safety 1 of 6 2
14.5 Apparatus and Equipment 1 of 6 2
14.6 Reagents and Consumable Materials 2 of 6 2
14.7 Sample Collection, Preservation, and Storage 2 of 6 2
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Contents (Continued)
Section Page Revision
14.8 Calibration and Standardization 2 of 6 2
14.8.1 Acetanilide Standards 2 of 6 2
14.8.2 Blank Samples 3 of 6 2
14.8.3 Calibration Sequence 3 of 6 2
14.8.4 Quality Control Calibration Standard 3 of 6 2
14.8.5 Linearity of Calibration Curve 4 of 6 2
14.9 Quality Control 4 of 6 2
14.10 Procedure 4 of 6 2
14.10.1 Vial Preparation 4 of 6 2
14.10.2 Sample Preparation 4 of 6 2
14.10.3 Determination of Total Carbon and Total Nitrogen 4 of 6 2
14.11 Calculations 5 of 6 2
14.12 Precision and Accuracy 6 of 6 2
14.13 References 6 of 6 2
15 Inorganic Carbon 1 of 5 2
15.1 Scope and Application 1 of 5 2
15.2 Summary of Method 1 of 5 2
15.3 Interferences 1 of 5 2
15.4 Safety 1 of 5 2
15.5 Apparatus and Equipment 1 of 5 2
15.6 Reagents and Consumable Materials 3 of 5 2
15.7 Sample Collection, Preservation, and Storage 3 of 5 2
15.8 Calibration and Standardization 4 of 5 2
15.9 Quality Control 4 of 5 2
15.10 Procedure 4 of 5 2
15.11 Calculations 4 of 5 2
15.12 Precision and Accuracy 4 of 5 2
15.13 References 4 of 5 2
16 Total Sulfur 1 of 3 2
16.1 Scope and Application 1 of 3 2
16.2 Summary of Method 1 of 3 2
16.3 Interferences 1 of 3 2
16.4 Safety 1 of 3 2
16.5 Apparatus and Equipment 1 of 3 2
16.6 Reagents and Consumable Materials 1 of 3 2
16.7 Sample Collection, Preservation, and Storage 2 of 3 2
16.8 Calibration and Standardization 2 of 3 2
16.9 Quality Control 2 of 3 2
16.10 Procedure 2 of 3 2
16.10.1 Sample Preparation 2 of 3 2
16.10.2 Determination of Sulfur 3 of 3 2
16.11 Calculations 3 of 3 2
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Contents (Continued)
Section Page Revision
16.12 Precision and Accuracy 3 of 3 2
16.13 References 3 of 3 2
17 Semiquantitative Analysis by X-Ray Powder Diffraction of the
<2-mm and <0.002-mm Fractions of Soil 1 of 12 2
17.1 Scope and Application 1 of 12 2
17.2 Summary of the Method 1 of 12 2
17.3 Interferences 1 of 12 2
17.4 Safety 1 of 12 2
17.5 Apparatus and Equipment 1 of 12 2
17.6 Reagents and Consumable Materials 2 of 12 2
17.7 Sample Collection, Preservation, and Storage 3 of 12 2
17.8 Calibration and Standardization 3 of 12 2
17.9 Quality Control 4 of 12 2
17.9.1 Sample Preparation 4 of 12 2
17.9.2 Sample Analysis 4 of 12 2
17.9.3 Indexing of Diffractograms 4 of 12 2
17.10 Procedure 4 of 12 2
17.10.1 Preparation and Analysis of the Multiphase
Reference Standard 4 of 12 2
17.10.2 Preparation of Randomly Oriented Powder Mounts from
the <2-mm Fraction of Soil Samples 6 of 12 2
17.10.3 Separation of the <0.002-mm Fraction from
the <20mm Fraction of Soil Samples 6 of 12 2
17.10.4 Preparation and Treatment of Oriented Slides from
the <0.002-mm Fraction of Samples for Identification
of Clay Minerals 7 of 12 2
17.10.5 Preparation of Randomly Oriented Powder Mounts from
the <0.002-mm Fraction of Soil Samples 9 of 12 2
17.11 Calculations 9 of 12 2
17.11.1 Mineral Identification and Quantification 9 of 12 2
17.12 Precision and Accuracy 11 of 12 2
17.13 References 11 of 12 2
18 Wavelength-Dispersive X-Ray Fluorescence Spectrometry 1 of 4 2
18.1 Scope and Application 1 of 4 2
18.2 Summary of Method 1 of 4 2
18.3 Interferences 1 of 4 2
18.4 Safety 1 of 4 2
18.5 Apparatus and Equipment 2 of 4 2
18.6 Reagents and Consumable Materials 2 of 4 2
18.7 Sample Collection, Preservation, and Storage 2 of 4 2
18.8 Calibration and Standardization 2 of 4 2
18.9 Quality Control 3 of 4 2
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Contents (Continued)
Section Page Revision
18.10 Procedure 3 of 4 2
18.10.1 Sample Preparation 3 of 4 2
18.10.2 Instrumental Requirements 3 of 4 2
18.11 Calculations 4 of 4 2
18.12 Precision and Accuracy 4 of 4 2
18.13 References 4 of 4 2
19 Scanning Electron Microscopy with Energy-Dispersive X-Ray
Fluorescence Analysis 1 of 5 2
19.1 Scope and Application 1 of 5 2
19.2 Summary of Method 1 of 5 2
19.3 Interferences 1 of 5 2
19.4 Safety 1 of 5 2
19.5 Apparatus and Equipment 1 of 5 2
19.6 Reagents and Consumable Materials 2 of 5 2
19.7 Sample Collection, Preservation, and Storage 2 of 5 2
19.8 Calibration and Standardization 2 of 5 2
19.9 Quality Control 2 of 5 2
19.10 Procedure 3 of 5 2
19.11 Calculation 4 of 5 2
19.12 Precision and Accuracy 4 of 5 2
19.13 References 4 of 5 2
Appendices
A Atomic Absorption Spectroscopy Methods 1 of 18 2
B Inductively Coupled Plasma Atomic Emission Spectrometric Method
for Trace Element Analysis of Water and Wastes 1 of 16 2
C Forms for Reporting Analytical Laboratory Data 1 of 62 2
D Forms for Reporting Mineralogical Laboratory Data 1 of 8 2
E Glossary 1 of 2 2
XIV
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Figures
Revision 2
Date: 12/86
Page 1 of 1
Figures
Section Page Revision
1-1 Map of regions of concern for the Direct/Delayed Response Project ... 2 of 9 2
1-2 Sequence of major activities associated with the Direct/Delayed
Response Project 4 of 9 2
1-3 Overall procedures for watershed classification as direct response,
delayed response, or capacity protected 5 of 9 2
1-4 Decision chart showing the mechanisms hypothesized to be important
in controlling surface water acidification 6 of 9 2
7-1 Mechanical extractor 3 of 10 2
8-1 Standard addition plot 8 of 15 2
12-1 Ion chromatography resolution test 6 of 8 2
15-1 Mineral carbon apparatus 2 of 5 2
xv
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Tables
Revision 2
Date: 12/86
Page 1 of 2
Tables
Section Page Revision
2-1 List of Parameters and Corresponding Analytical Techniques 4 of 18 2
2-2 Summary of Internal Quality Control 5 of 18 2
2-3 Maximum Control Limits for QC Samples 13 of 18 2
2-4 Required Detection Limits, Expected Ranges, and Intralaboratory
Relative Precision Goal 15 of 18 2
2-5 Index of Data Forms 17 of 18 2
2-6 Laboratory/Field Data Qualifiers 18 of 18 2
2-7 List of Decimal-Place Reporting Requirements 18 of 18 2
2-8 Mineralogical Parameters and Corresponding Analytical Techniques ... 18 of 18 2
4-1 Sedimentation Times for Particles of less than 0.002, less than
0.005, and less than 0.002 mm Diameter Settling through Water
for a Depth of 10 cm 4 of 6 2
4-2 Sedimentation Times and Pipetting Depths for Particles of <0.002 mm 5 of 6 2
7-1 Typical Purpose and Size of Each Pump Tube 8 of 10 2
8-1 Expected Range of Analyte Concentrations in Soil Extracts 1 of 15 2
8-2 Atomic Absorption Performance Data for Determination of Ca2+, Mg2+,
K+, and Na+ 2 of 15 2
8-3 Recommended Wavelengths and Estimated Instrumental Detection
Limits for Inductively Coupled Plasma Analysis 2 of 15 2
8-4 Precision and Accuracy Data for Inductively Coupled Plasma 14 of 15 2
10-1 Atomic Absorption Performance Data for Determination of Fe3+ 1 of 7 2
10-2 Recommended Wavelengths and Estimated Instrumental Detection
Limits for Determination of Fe3+ and AI3+ by Inductively Coupled
Plasma 1 of 7 2
10-3 Inductively Coupled Plasma Precision and Accuracy Data 6 of 7 2
11-1 Atomic Absorption Performance Data for Determination of
Fe3+ and AI3+ 1 of 7 2
XVI
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Tables
Revision 2
Date: 12/86
Page 2 of 2
Tables (Continued)
Section Page Revision
12-1 Example of Concentration of Calibration Standards used for the
Analysis of Water Samples by Ion Chromatography 3 of 8 2
12-2 Single-Operator Precision and Accuracy 7 of 8 2
14-1 Allowable Deviations in K-Factors 3 of 8 2
14-2 Allowable Blank Variations 3 of 6 2
17-1 Effect of Some Diagnostic Treatments on Spacing of First Low Angle
Reflection of Clay Minerals 10 of 12 2
18-1 Optimum Combination of Operational Conditions 4 of 4 2
A-1 Atomic Absorption Concentration Ranges 2 of 18 2
B-1 Recommended Wavelengths and Estimated Instrumental Section Limits 2 of 16 2
B-2 Analyte Concentration Equivalents (mg/L) Arising from Interferents
at the 100 mg/L Level 5 of 16 2
B-3 Interferent and Analyte Elemental Concentrations Used for Interference
Measurements in Table B-2 5 of 16 2
B-4 ICP Precision and Accuracy Data 15 of 16 2
xvii
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Acknowledgements
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Page 1 of 1
Ackno wledgments
Critical reviews by the following individuals are gratefully acknowledged: S. A. Abboud,
Alberta Research Council, Edmonton, Alberta, Canada; M. W. Findlay, Jr., Argonne National
Laboratory, Argonne, Illinois; D. F. Grigal, University of Minnesota-Twin Cities, St. Paul, Minnesota;
G. R. Holdren, Northrop Services, Inc., Corvallis, Oregon; R. Jenkins, JCPDS-International Centre for
Diffraction Data, Swarthmore, Pennsylvania; M. J. Mitchell, State University of New York, Syracuse,
New York; and G. Pierzynski, The Ohio State University, Columbus, Ohio.
The guidance of the following people was important in the documentation of the chemical and
physical methods: D. C. Hillman and S. J. Simon, Lockheed Engineering and Management
Services Company, Inc., Las Vegas, Nevada; I. Fernandez, University of Maine, Orono, Maine;
F. M. Kaisaki, L Juve (retired), L Shields (retired), and others at the U. S. Department of
Agriculture, Soil Conservation Service, National Soil Survey Laboratory, Lincoln, Nebraska;
K. Doxsee, S. Vincent, and others at Weyerhaeuser Research and Technology Center, Federal Way,
Washington; K. L Weisgable and Colin Williams, The Perkin-Elmer Corporation, Norwalk,
Connecticut; G. Ferguson, Cornell University, Ithaca, New York; E. W. D. Huffman, Jr., and
R. G. Boyd, Coulometrics, Inc., Wheatridge, Colorado; R. N. Heistand, D. Raines, and others at
Huffman Laboratories, Golden, Colorado; F. S. Latenser, D. Hartford, and K. Shields, Harris Labora-
tories, Inc., Lincoln, Nebraska; C. Trenton, Ford Forestry Center, Alberta, Michigan; P. Shaffer,
Northrop Services, Inc., Corvallis, Oregon; D. Johnson, Oak Ridge National Laboratory, Oak Ridge,
Tennessee; J. Reuss and M. Walthall, Colorado State University, Ft. Collins, Colorado; D. S. Coffey,
formerly of Northrop Services, Inc., Corvallis, Oregon; J. J. Lee, U. S. Environmental Protection
Agency, Environmental Research Laboratory, Corvallis, Oregon; and R. W. Arnold, U. S. Department
of Agriculture, Washington, D. C.
Consultation with the following people was important in the documentation of the
mineralogical methods: G. R. Holdren and M. E. Johnson, Northrop Services, Inc., Corvallis, Oregon;
D. Bish, Los Alamos National Laboratory, Los Alamos, New Mexico; E. Smith, University of Nevada,
Las Vegas, Nevada; J. Baham, G. Campi, and A. Soeldner, Oregon State University, Corvallis,
Oregon; and M. Slaughter, Colorado School of Mines, Golden, Colorado.
The following people were instrumental in the completion of this manual: M. L. Faber and
J. M. Nicholson of Lockheed Engineering and Management Services Company, Inc.; Computer
Sciences Corporation word processing staff and Donald Clark Associates graphic arts staff at the
U. S. Environmental Protection Agency, Environmental Monitoring Systems Laboratory, Las Vegas,
Nevada.
Finally, recognition belongs to E. P. Meier and P. A. Arberg who have served as technical
monitors of this project.
XVIII
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/ Introduction
1.1 Project Overview
The U.S. Environmental Protection Agency
(EPA), in conjunction with the National Acid
Precipitation Assessment Program (NAPAP),
has designed and implemented a research
program to predict the long-term response of
watersheds and surface waters in the United
States to acidic deposition. On the basis of
this research, each watershed system studied
will be classified according to the time scale in
which it will reach an acidic steady state,
assuming current levels of acidic deposition.
The three classes of watersheds are defined
as follows:
• Direct response systems-Watersheds
in which surface waters are presently
acidic (i.e., alkalinity < 0 jueq/L) or will
become acidic within 3 to 4 mean
water residence times (i.e., within 10
years). A mean water residence time
is the average time period required to
replenish totally the water contained
in a lake.
• Delayed response systems-Water-
sheds in which surface waters will
become acidic in the time frame of a
few mean residence times to several
decades (i.e., 10 to 100 years).
• Capacity Protected ^stems-Water-
sheds in which surface waters will not
become acidic for centuries to millen-
nia.
As an element of NAPAP, the National
Surface Water Survey (NSWS) was initiated to
evaluate the water chemistry of lakes and
streams, to determine the status of fisheries
and other biotic resources, and to select
regionally representative surface waters for
a long-term monitoring program that will
study future changes in aquatic resources.
Subsequently, the Direct/Delayed Response
Project (DORP) was designed as the soil study
complement to NSWS.
For DDRP, EPA is testing the hypothesis
that atmospheric deposition of sulfur plays the
principal IQ\Q in controlling long-term acidifica-
tion of surface waters (EPA, 1985a). There-
fore, DDRP is "concerned with the effects on
surface water chemistry related to deposition
of sulfur only. If a 'direct' response exists
between sulfur deposition and surface water
alkalinity, then the extent of current effects on
surface water probably would not change
much at current levels of deposition, and
conditions would improve as the levels of
deposition decline. If surface water chemistry
changes in a 'delayed' manner (e.g., due to
chemical changes in the watershed), then
future changes in surface water chemistry
(even with level or declining rates of deposi-
tion) become difficult to predict. This range of
potential effects has clear and significant
implications to public policy decisions on
possible additional emissions control [require-
ments for sulfur emission sources]" (EPA,
1985b).
DDRP, like NSWS, focuses on areas of
the United States that have been identified as
potentially sensitive to surface-water acidifica-
tion. Two regions, the Northeast and the
Southeast (see Figure 1-1), have been included
in the DDRP soil survey. The Northeastern soil
survey includes the New England states of
Maine, New Hampshire, Vermont, Massachu-
setts, Connecticut, and Rhode Island, and
portions of the states of New York and Penn-
sylvania. The Southeastern soil survey fo-
cuses on the area that is identified physio-
graphically as the Southern Blue Ridge Prov-
ince: bordering portions of Tennessee, North
Carolina, South Carolina, and Georgia as well
as portions of Virginia. Surface waters in
these two regions were studied during the
NSWS Eastern Lake Survey Phase I (1984) and
the NSWS National Stream Survey - Pilot Study
(1985).
Specific goals of the DDRP soil survey
are (1) to define physical, chemical, and miner-
alogical characteristics of the soils and to
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define other watershed characteristics across
these regions, (2) to assess the variability
of these characteristics, and (3) to determine
which of these characteristics are most
strongly related to surface-water chemistry.
Additional DDRP goals are (4) to estimate the
relative importance of key watershed pro-
cesses in controlling surface-water chemistry
across the regions of concern, and (5) to
classify the sample of watersheds as direct
response, delayed response, or capacity pro-
tected (to the degree that is scientifically
defensible) and to extrapolate the results from
the sample of watershed to the regions of
concern.
The general sequence of activities for
DDRP is shown in Figure 1-2. A subset of
watersheds was chosen from watersheds
studied during NSWS. Following detailed
mapping of the selected watersheds, the
mapping units were aggregated into sampling
units. Each sampling unit was composed of
mapping units which were thought to have
similar soil chemistry because of similarities in
characteristics such as drainage and parent
material. Representative sampling sites were
chosen on several watersheds for each sam-
pling unit, and samples were taken from each
soil horizon at the selected sites. After
preparation, the soil samples were ana-
lyzed for physical, chemical, and mineralogical
characteristics.
A variety of data sources and methods
of analysis will be used to address the
objectives of DDRP. Figure 1-3 illustrates
the strategy by which data will be integrated
to achieve these objectives. In addition to the
data collected during DDRP, data sources
include other existing data, e.g., surface water
data collected during NSWS, the Acid Deposi-
tion Data Network Data Base (ADDNET),
GEOECOLOGY, the Soil Conservation Service
(SCS) Soils-5 Data Base, and the Adirondack
Watershed Data Base. The proposed methods
of data analysis fall into three levels of com-
plexity: (1) system description, (2) single-
factor response time estimates, and (3) dy-
namic systems modeling. Each level of analy-
sis involves decision criteria (see Figure 1-4)
that are used to classify watersheds as direct
response, delayed response, or capacity pro-
tected. After the representative watersheds
are classified, the results will be extrapolated
to classify the response time of each water-
shed in a given region.
1.2 Field Activities
The soils mapping of the watersheds
was done by U.S. Department of Agriculture
(USDA)/Soil Conservation Service (SCS) per-
sonnel using the standard National Coopera-
tive Soil Survey procedures which are docu-
mented in Soil Survey Manual (USDA/SCS,
1951). After sampling sites were selected
according to protocols developed by EPA (EPA,
undated), each site was excavated, and the
soil profile was described according to stan-
dard SCS protocol (USDA/SCS, 1975). Sam-
ples of these representative soils were taken
by using modified SCS procedures (Blume et
al., 1987).
The following watershed and soil profile
characteristics were documented for each
sampling site:
• Geology
- type of bedrock
- percent of bedrock exposed
- degree of fractionation
- type of parent material (e.g., till,
outwash, alluvium, colluvium, resid-
uum, lacustrine or marine sedi-
ments, eolian sands)
• Site description
- site position (e.g., upland, flood
plain, stream terrace, moraine,
depression, kame terrace)
- percent slope
- average slope length and configura-
tion
- stream type and density
- vegetation type (overstory and
understory)
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Direct/Delayed
Response Project
Activities
Conduct National Surface Water Survey
1. National Lake Survey
2. National Stream Survey
I
Statistically select representative
watersheds from NSWS Northeastern and
Southern Blue Ridge regions
i
Conduct Soil Survey to assess soil
variability and watershed acid
neutralization capacities
I
Compile all relevant water chemistry.
soil, and watershed data from NSWS,
Soil Survey, and intensive watershed
studies
I
Conduct Level I. II, and III analyses
to classify watersheds as direct
response, delayed response, or
capacity protected
I
Extrapolate watershed response results
to entire regions
I
Conduct long-term watershed monitoring
to verify watershed classifications
Figure 1-2. Sequence of major activities associated with the Direct/Delayed Response Project (modified
from Radian Corporation, 1985).
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The National Surface Water
Survey provides surface
water chemistry data
Statistical analyses to select
watersheds for Soil Survey
Soil Survey Watersheds
Alkalinity
Oueq/L
Direct Response Watershed
Watershed Classification Level I
Statistical analyse!
Input-output budgets
System description
Delayed Response/
Capacity Protected
Watersheds
Alkalinity
400 peq/L
Capacity Protected Watershed
Watershed Classification Level II
Surfate adsorption
Percent base saturation
Soil contact
T>100yrs
Delayed Response/
Capacity Protected
Watersheds
Capacity Protected Watershed
Watershed Classification Level III
Trickle-down
Magic
ILWAS
i
Capacity Protected Watershed
Delayed Response Watershed
Figure 1-3. Overall procedures for watershed classification as direct response, delayed response, or capacity
protected (modified from Radian Corporation, 1985).
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Acidic Atmospheric Inputs
-Location
-Climate, seasonally
-Physiography
-Canopy type
Soil/Sediment Contact
-Hydrologic flow paths
-Flow rate/reaction time
Weathering Replacement
-Weathering rates
-Mineralogy
Anion Retention
-Sulfate adsorption capacity
-Percent capacity filled
-Solution concentration
-Nitrate availability
Base Cation Buffering
-Base saturation
-Cation exchange capacity
-Vegetation withdrawal
or redistribution
Salt Effect Alkalinity Depression
-Base saturation
-Weak acid buffering
-In-stream/in-lake processes
• N
o
N
N
N
N
N
t)
Capacity Protected
Delayed Response
Direct Response
Decision Points
Y^Yes
Saturation/Depletion
of Delay Mechanism
NOTE: Each arrow points to the outcome that would be expected (direct/delayed/capacity
protected). When a particular controlling mechanism is in effect for a given watershed.
Subheadings indicate environmental factors thought to control each mechanism.
Figure 1-4. Decision chart showing the mechanisms hypothesized to be Important In controlling surface water
acidification (modified from Radian Corporation, 1985).
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• Soil morphology by horizon
- horizon designation
- depth (upper and lower boundaries)
- type of boundary
- Munsell color
- structure
- consistence
- drainage class
- mottles (location, color, distinct-
ness, frequency)
- root distribution
- presence of impermeable layers
- texture (including rock fragments)
1.3 Laboratory Activities
The handling of soil samples at each
preparation laboratory is summarized in Sec-
tion 2.1. In addition to sample processing, air-
dry moisture content, percent rock fragments
in the 2-mm to 20-mm size fraction, and bulk
density are determined at each preparation
laboratory. The physical, chemical, and miner-
alogical procedures presented in detail in
sections 3 through 19 are summarized below:
A. Physical Parameters
1. Moisture Content-k standard soil testing
method is used to determine soil mois-
ture content on a dry weight basis. Air-
dry soil is weighed, dried in an oven,
then reweighed. The moisture content is
then used to place all measurements on
an oven-dry basis.
2. Particle Size-Soil textural analysis is
routinely determined for soil character-
ization and classification purposes. The
standard pipet method is used. Rock
fragments greater than 2 to 20 mm are
determined by field sieving and weighing.
Rock fragments 2 to 20 mm are deter-
mined at the soil preparation laboratory,
and particles less than 2 mm are deter-
mined at the analytical laboratory.
3. Specific Surface-k gravimetric method
that employs saturation with ethylene
glycol monoethyl ether (EGME) is used
to measure specific surface. Specific
surface is highly correlated to cation
exchange capacity, sulfate adsorp-
tion, analyte adsorption/desorption,
and the type of clay mineral.
B. Physical/Chemical Parameters
1. pM-pH is an indication of free hydrogen
ion activity. pH measurements are deter-
mined in three soil suspensions: one in
deionized water, one in 0.01 M CaCI2,
and one in 0.002 M CaCI2.
2. Cation Exchange Capac/ty-Cation ex-
change capacity (CEC) is a standard soil
characterization parameter. CEC indi-
cates the ability of a soil to adsorb cat-
ions, especially the exchangeable basic
cations, Ca2+, Mg2+, K+, and Na+. CEC
is highly correlated with the buffering
capacity of the soil. Two saturating
solutions are used: buffered ammonium
acetate (NH4OAc) solution to measure
total CEC and neutral ammonium chlo-
ride (NH4CI) solution to measure effective
CEC. Analysis is by titration or by flow
injection analysis.
3. Exchangeable Basic Cat/ons-Jbe ex-
changeable basic cations, Ca2+, Mg2+,
K+, and Na+ extracted during the CEC
determinations, are determined by atom-
ic absorption (AA) or by inductively
coupled plasma (ICP). Measurement of
the level of exchangeable basic cations
indicates the base saturation of the soil.
4. Exchangeable >4c/br//y--Exchangeable
acidity is a measure of the exchangeable
cations that are not part of the base
saturation. Two methods of analysis
are used. One employs a buffered
BaCI2-TEA extraction; the other, a neutral
1.0 N KCI extraction. The BaCI2-TEA
method is a back-titration method which
indicates total exchangeable acidity. The
KCI method is a direct titration method
which estimates effective exchangeable
acidity. KCI-extractable Al is determined
by AA or by ICP.
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C. Chemical Parameters
1. Lime and Aluminum Potentiaf~L\rr\e po-
tential is used in place of base satura-
tion as an input for certain models. Lime
potential is defined as pH - 1/2 pCa.
Another characteristic important to wa-
tershed modeling is the relationship of
pH to solution AT* levels. This is defined
as aluminum potential (KJ which is equal
to 3pH - pAI. This method involves ex-
tracting soil with 0.002 M CaCI2 and
determining Ca2+ and AJ3+ in the extract.
The cations, Na+, K+ and Mg2+, and ex-
changeable Fe3+ are also determined in
this extract for comparison to cation
concentrations in other extracts.
2. Extractable Iron and Aluminum-Iron and
aluminum oxides are highly correlated to
sulfate adsorption and are important in
standard soil characterization. Extract-
able Fe and Al are determined by AA or
by ICP in three different extracts. Each
extract yields an estimate of a specific
Al or Fe fraction. The three fractions of
extractable iron and aluminum include
those extracted by: sodium pyrophos-
phate which estimates organic Fe and
Al, ammonium oxalate which measures
organic Fe and Al plus sequioxides, and
citrate-dithionite which indicates non-
silicate Fe and Al. Analysis is performed
by AA or by ICP.
3. Extractable Sulfate and Mtrate-The
amount of extractable sulfate and nitrate
indicates the sulfate and nitrate satura-
tion of the anion exchange sites. Sulfate
is determined in two different extracts:
deionized water and 500 mg P/L sodium
phosphate. Nitrate is determined only in
the deionized water extract. Analysis is
by ion chromatography.
4. Sulfate Adsorption Isotherms-The ability
of soil to adsorb sulfate is related to soil
buffering capacity. Isotherms are devel-
oped by placing soil samples in six mag-
nesium sulfate solutions of different
concentrations: 0, 2, 4, 8, 16, and 32 mg
S/L. Then the amount of sulfate
remaining in solution after contact with
the soil is determined. Subtraction yields
the amount of sulfate adsorbed by the
soil. These isotherms represent the
maximum sulfate adsorption capacity of
the soil under laboratory conditions.
5. Total Carbon and Total Mtrogen-These
two parameters are closely related to
soil organic matter type. The method of
analysis is rapid oxidation followed by
thermal conductivity detection using an
automated CHN analyzer.
6. Inorganic Carbon-Inorganic carbon is
quantified because of the inherent ability
of carbonates to buffer acidic input. In
soils with a water pH greater than or
equal to 6.0, carbonates are determined
by coulometric detection of evolved CO2
after decomposition with a strong acid.
7. Total Sulfur-~\oia\ sulfur is measured to
inventory existing sulfur levels in order to
monitor future input of anthropogenic
sulfur. An automated method involving
sample combustion followed by infrared
detection or titration of evolved sulfur
dioxide is specified.
D. Mineralogical Parameters
1. Semiquantitative X-Ray Diffraction~T\\e
mineral content is quantified by X-raying
the samples selected for mineralogical
study. To determine the mineral content,
the samples are X-rayed and are com-
pared against mineral standards for
quantification. Physical separations of
the <0.002-mm fraction and the 2-mm to
0.002-mm fractions are required.
2. X-Ray Huorescence-Trus method gives
the general chemistry of the bulk sample
and of the clay fraction. The samples
are pulverized, pressed into pellets, and
analyzed. These data combined with
data from X-ray diffraction identify the
distribution of the elements.
3. Scanning Electron Microscopy/Energy
Dispersive XRF-W\\\\ these two methods,
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1.4
topographic features are examined, and
local chemistry of discrete particles is
analyzed. These results give information
concerning type and degree of weather-
ing.
Quality Assurance/Quality
Control
Throughout the DDRP soil survey, rigorous
quality assurance (QA)/quality control (QC)
procedures were followed. The QA project
plan (Bartz et al., 1987) documents the QA/QC
requirements for soil sampling, preparation,
and analysis. Internal QC requirements for
analytical procedures also are summarized in
Section 2.6 and are presented in sections 3
through 16 for each method.
1.5 Data Handling
A summary of the plan for data handling
and data verification is given in Bartz et al.
(1987). Data collected for DDRP will be main-
tained in a computerized data base by Oak
Ridge National Laboratory. To facilitate inter-
pretation of watershed and soils data, the
data management system used for DDRP is
compatible with the NSWS data base.
1.6 References
Bartz, J. K., S. K. Drouse, M. L Papp, K. A.
Cappo, G. A. Raab, L. J. Blume, M. A.
Stapanian, F. C. Garner, and D. S. Coffey.
1987. Direct/Delayed Response Project:
Quality Assurance Plan for Soil Sampling,
Preparation, and Analysis. U.S. Environ-
mental Protection Agency, Las Vegas,
Nevada.
Blume, L. J., M. L. Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sampl-
ing Manual for the Direct/Delayed
Response Project Soil Survey. U.S. Envi-
ronmental Protection Agency, Las Vegas,
Nevada.
Appendix A In: Direct/Delayed Response
Project Southern Blue Ridge Province Field
Sampling Report: Vol. I Field Sampling. U.S.
Environmental Protection Agency.
Radian Corporation. 1985. Overview of the
Direct/Delayed Response Project (First Draft).
Prepared for R. Linthurst, U.S. Environmental
Protection Agency, Research Triangle Park,
North Carolina.
U.S. Department of Agriculture/Soil Con-
servation Service. 1975. Soil Taxonomy.
Handbook 436. U.S. Government Printing
Office, Washington, D. C.
U.S. Department of Agriculture/Soil Con-
servation Service. 1951. Soil Survey Manual.
Handbook 18, U.S. Government Printing Office,
Washington, D. C.
U.S. Environmental Protection Agency.
1985a. Direct/Delayed Response Project:
Long-Term Response of Surface Waters to
Acidic Deposition: Factors Affecting Response
and a Plan for Classifying Response Charac-
teristics on Regional Scales, Vol. II: Part A,
State of Science. U.S. Environmental Protec-
tion Agency, Environmental Research Laborato-
ry, Corvallis, Oregon.
U.S. Environmental Protection Agency.
1985b. Direct/Delayed Response Project:
Long-Term Response of Surface Waters to
Acidic Deposition: Factors Affecting Response
and a Plan for Classifying Response Charac-
teristics on Regional Scales, Vol. V: Appendix
B.2 Soil Survey-Action Plan/Implementation
Protocol. U.S. Environmental Protection Agen-
cy, Environmental Research Laboratory, Corval-
lis, Oregon.
U.S. Environmental Protection Agency.
Undated. Direct/Delayed Response Project:
Definition of Soil Sampling Classes and Selec-
tion of Sampling Sites for the Northeast. U.S.
Environmental Protection Agency, Environmen-
tal Research Laboratory, Corvallis, Oregon.
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2 Laboratory Operations
2.1 Preparation Laboratory
Procedures
Soil samples are processed by a prepa-
ration laboratory before they are shipped to
the analytical laboratory. When not undergo-
ing preparation or subsequent analysis, soil
samples are refrigerated at 4 °C. All samples
are air-dried, crushed, and homogenized.
Samples are tested for air-dried moisture
content, percent rock fragments, and the
presence of inorganic carbon. For each sam-
ple, a subsample of approximately 1 kg is split
from the bulk sample by using a riffle splitter.
The remaining bulk sample is archived.
Air-dry moisture content is determined as
follows: An air-dry subsample is removed
from the bulk sample, is weighed, and is
placed in a convection oven for 24 hours at the
prescribed temperature, 105 °C for mineral
soils and 60 °C for organic soils. After it is
oven-dried, the sample is reweighed, and the
percent moisture lost is calculated.
The rock fragment determination is
performed as follows: Each soil sample is
weighed, then it is sieved to separate the rock
fragments greater than 2 mm from the less
than 2-mm, fine earth material. The rock
fragments are separated by sieving into two
size fractions: the 2-mm to 4.75-mm fraction
and the 4.75-mm to 20-mm fraction. Each
fraction is weighed, and the percent rock
fragments in each size fraction is calculated.
For each sample, a qualitative test for
inorganic carbon, i.e., carbonate, is performed
as follows: Duplicate 1-g aliquots of the less
than 2-mm material are placed on a porcelain
spot-plate and are saturated with water. The
soil is placed under a binocular microscope
that has a reflected light source and is ob-
served as a few drops of 4 N HCI are added.
Effervescence indicates the presence of inor-
ganic carbon. If the test for inorganic carbon
is positive, rock fragments in the 2-mm to
20-mm fraction are crushed to pass a 2-mm
sieve and are subsampled by using a riffle
splitter. The subsample is ground to pass an
80-mesh sieve and is submitted to the analyti-
cal laboratory for inorganic carbon analysis.
Samples are combined into analytical
batches. All samples in a set, i.e., the sam-
ples taken by a sampling crew within one day
and including one field (or sampling) duplicate,
are assigned to an analytical batch. Three to
eight sets are combined to create one analyti-
cal batch of as many as 39 routine and field
duplicate samples. One sample per batch is
split to form a preparation duplicate. A mini-
mum of two audit samples, supplied by the
quality assurance (QA) staff, are included in
each analytical batch. All samples within the
batch are randomly assigned analytical sample
numbers (Bartz et al., 1987b).
For further detail about the preparation
laboratory and its operations, refer to Bartz et
al. (1987a).
2.2 Sample Receipt and
Handling at the Analytical
Laboratory
All samples received by the analytical
laboratory are checked in by a receiving clerk
who (1) records on the shipping form the date
samples are received, (2) checks the samples
to identify discrepancies with the shipping
form, and (3) mails a copy of the completed
shipping form to the appropriate addresses.
If there are any discrepancies or problems
such as leakage or insufficient sample, these
problems must be documented. The receiving
clerk retains a copy of the completed shipping
form for the laboratory records. The samples
are refrigerated at 4 °C as soon as possible
and must be refrigerated when not in use.
During shipping, the sample material
within each container segregates both by
particle size and by density; therefore, each
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sample must be homogenized by thorough
mixing prior to the removal of aliquots for
analysis. One method is to place sample
material on a 60-cm by 60-cm square of heavy
white paper. Next, lift each corner of the
paper alternately and roll the soil toward the
opposite corner. Continue until the soil has
been rolled toward each corner 20 times.
Carefully return the sample to the sample
container. Alternative methods of homogeniz-
ing the sample may be used.
Prior to the removal of an aliquot for
analysis, the sample is thoroughly mixed within
the sample container. After an aliquot is
removed for analysis, the sample is returned
to refrigerated storage as soon as possible.
After all analyses have been completed
and the results have been checked, samples
are stored in a refrigerator at 4 °C, in case
reanalysis is necessary.
2.3 Cleaning Procedures for the
Analytical Laboratory
Clean all materials that come into con-
tact with the samples, e.g., AutoAnalyzer and
autosampler tubes, cups, as described below.
Whenever double-deionized (DDI) water is
noted, the water must be double-distilled,
double-deionized, or deionized and distilled to
meet purity specifications for ASTM Type II
Reagent Water given in ASTM D 1193 (ASTM,
1984).
2.3.1 Plasticware to be used for pH,
Acidity, Alkalinity, Cation
Exchange Capacity (CEC)
Titrations, and Anion
Determinations
For new plasticware, rinse each contain-
er with reagent grade methanol or ethanol. In
cleaning plasticware for reuse, the alcohol
rinse may be omitted. Also, repeat this step
whenever an oily residue appears. Rinse each
container three times with DDI water, empty
the container, and invert it to dry. Protect each
container from contamination prior to use.
After the initial cleaning, check 5 per-
cent of the containers to ensure that rinsing
has been adequate. Perform the check as
follows:
Add 500 mL, or the maximum volume if
the capacity of the container is less than 500
ml, of DDI water to each clean, dry container.
Seal the container with a cap or with Parafilm,
then rotate the container slowly until the water
touches all surfaces.
Remove the cap, and measure the con-
ductivity of the contained water. The conductiv-
ity must be less than 1 jumho/cm. If any of
the containers fail the check, rerinse all the
containers and perform the check again on 5
percent of the rerinsed containers.
When the plasticware containers pass
the check, place the containers, capped or
covered with Parafilm, in plastic bags which
will remain sealed until the containers are used
for sample analysis.
Syringes and centrifuge tubes may
require the use of a brush and detergent to
remove adhering soil particles. A detergent
wash must be followed by at least three
tap water rinses followed by three DDI water
rinses. Containers should be checked as
described above.
2.3.2 Other Plasticware
Rinse plasticware with reagent grade
methanol or ethanol, then continue cleaning as
described for glassware (Section 2.3.3).
2.3.3 Glassware
Rinse each container three times with
DDI water, then rinse the container three times
with 3N HNO3 or HCI (prepared from Baker
Instra-analyzed acid or equivalent), then rinse
the container six times with DDI water.
Allow the container filled with DDI water
to stand overnight. Empty the container, invert
it, and allow it to dry. All volumetric glassware
should be air-dried. When dry, cap or cover
containers with Parafilm. Place glassware In
-------
Section 2
Revision 2
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Page 3 of 18
a clean plastic bag until it is needed for analy-
sis.
Kjeldahl flasks should be cleaned with
Hj,SO4 acid because it is a better scavenger for
ammonium ion. Sedimentation cylinders may
be cleaned as follows: The acid rinse may be
omitted. Brushing may be required to remove
adhering soil particles and, in extreme cases,
a detergent wash followed by at least three
tap-water rinses and sixdeionized-water rinses
may be used.
2.4 Procedure for Washing
Filter Pulp
The filter pulp, used in conjunction with
the mechanical extractor for procedures involv-
ing extraction by leaching, is a potential source
of contamination. Acidity is produced as wood
products age. The filter pulp also contains
significant amounts of cations that are often
greater than the soil sample concentrations.
To alleviate the contamination problem, wash-
ing the filter pulp prior to sample analysis is
recommended.
After the sample tube is prepared and is
attached to the mechanical extractor as speci-
fied in the procedure, the reservoir syringe is
filled with approximately 50 ml_ of the appropri-
ate extracting solution. The solution is leached
through the filter pulp and is collected in a
waste recovery syringe. Excess solution
retained in the pulp is removed by vacuum.
The solution retained in the filter pulp will
contribute to the dilution factor; therefore, it is
important that excess solution be removed so
that this effect may be considered negligible.
2.5 Sample Analyses by the
Analytical Laboratory
A summary of physical and chemical
parameters to be measured by the analytical
laboratory and the corresponding analytical
techniques is presented in Table 2-1. The
detailed procedures for physical and chemi-
cal parameters are described in sections 3
through 16. Each section addresses the
following:
2.6
1. Scope and Application
2. Summary of Method
3. Interferences
4. Safety
5. Apparatus and Equipment
6. Reagents and Consumable Materials
7. Sample Collection, Preservation,
and Storage
8. Calibration and Standardization
9. Quality Control
10. Procedure
11. Calculations
12. Precision and Accuracy
13. References
Internal Quality Control
Within Each Analytical
Method
Internal quality control (QC) is an integral
part of any measurement procedure in order to
ensure that results are reliable. A summary of
internal QC procedures for each method is
given in Table 2-2. QC procedures are indi-
cated in the appropriate method description.
Details on internal QC procedures are de-
scribed below.
2.6.1 Initial Calibration
Prepare all calibration standards in
concentration units of mg/L or as specified in
the procedure. Establish a calibration curve
for each analytical method by using a mini-
mum of three points within the linear range.
The use of at least a three-point calibration
curve is required in place of the manufacturer's
recommendations for the instrumentation,
unless those recommendations require more
than three points within the linear range. The
concentration of standards must bracket the
expected sample concentration without exceed-
ing the linear range of the instrument. Occa-
sionally the standards suggested by a method
must be adjusted to meet this requirement.
The lowest standard should not be greater
than 10 times the detection limit.
Next, determine the linear dynamic range
(LDR) for the initial calibration. If during the
analysis the concentration of a sample falls
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Table 2-1. List of Parameter* and Corresponding Analytical Technique*
Parameter
Method
Moisture
Sand
Silt
Clay
pH in deionized water
pH in 0.01 M CaCI,
pH in 0.002 M CaCI,
Total C
Total N
TotalS
Inorganic C
CEC (NH4OAc saturating solution)
CEC (NH.CI saturating solution)
Ca
Mg Exchangeable in NH.OAc, NH.CI, and CaCI,
Na
Gravimetric
Sieve/gravimetric
Pipet/gravimetric
Pipet/gravimetrtc
Combination electrode/millivoltmeter
Elemental analyzer
Elemental analyzer
Elemental analyzer
Coulometric
Autotitration/flow injection analyzer
Flame atomic absorption spectroscopy,
inductively coupled plasma atomic
emission spectroscopy (or flame atomic
emission spectroscopy for Na only)
K Exchangeable in NH.OAc, NH.CI, and CaCI,
Fe Exchangeable in CaCI,; extractable in
pyrophosphate, acid oxalate, and citrate-
dithionite
Al Extractable in pyrophosphata, acidoxalate,
and citrate-dithionite
Al Exchangeable in CaCI, and KCI
Nitrate (NO,-' Water extractable
Sulfate (SO.-' Water extractable, phosphate
extractable, and sulfate adsorption 6-point
isotherm
Exchangeable acidity in BaCI.-Trtethanolamine
and KCI saturating solutions
Specific surface
Flame atomic absorption spectroscopy
or flame atomic emission spectroscopy
Flame atomic absorption spectroscopy
or inductively coupled plasma atomic
emission spectroscopy
Inductively coupled plasma atomic
emission spectroscopy
Ion chromatography
Ion chromatography
Titrimetric
Gravimetric
above the LDR, two options are available. The
first option is to dilute and reanalyze the
sample. In this case, the diluent should have
the same matrix as the sample matrix The
second option is to calibrate two concentration
ranges. Samples are first analyzed on the
lower concentration range. Any samples
whose concentrations exceed the upper end of
the LDR are then reanalyzed on the higher
concentration range. If this option is per-
formed, separate QC calibration samples
(QCCS) must be analyzed and reported for
each range.
Spectroscopic-grade or high purity chemi-
cals are required for primary standards when
analysis is done by atomic absorption or
emission methods. Also, calibration standards
must have the same matrix as the solutions
being analyzed. In order to meet the detection
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Table 2-2. Summary of Internal Quality Control
Parameter
Procedure
Control Limits
Corrective Action
Moisture
aboratorv Triplicate
Particle Size
Analysis
Specific Surface
Analyze two additional
portions of one sample in
each batch.
: Calibration Sample
Analyze a QCCS after every
10 or fewer samples.
Laboratory Duplicate
Analysis
Analyze a second portion of
one sample in every batch.
Precision should be within
10% BSD.
Precision should be ±5% for
sand, silt, and clay
fractions a5% (wt/wt).
Precision should be ±5% for
sand, silt, and clay
fractions £5% (wt/wt).
Calibration Sample
Analyze 1 QCCS per batch of
21 or fewer samples, and 2
QCCS per batch of 22 or
more samples. Note: N,
adsorption standards may
be purchased from Duke
Scientific Corp., Palo Alto,
California.
Laboratory Triplicate
Analysis
Analyze two additional
portions of one sample in
every batch.
Reagent Blank Analysis
Analyze three reagent blanks
per batch containing an
amount of EGME equal to
the greatest quantity
required to saturate the soil
samples.
Precision should be within
10% RSD.
Precision should be within
10% RSD.
Blanks show no EGME
residual at end of equilibrium
period.
Analyze a second sample
in triplicate. If not within
control limits, check
temperature stability of the
oven and repeat triplicate
analyses.
Recalibrate balance,
volumetric pipet, and
thermometer. Check water
bath or room temperature.
Then reanalyze QCCS and
samples bracketed by the
affected QCCS.
Analyze a second sample
in duplicate. Determine
the source of imprecision;
homogenization of sample
may have been inadequate.
Recalibrate balance.
Check sieves for broken
wires. Reanalyze the
batch.
Continue desorption of
EGME with continuous
vacuum. Check CaCI, in
desiccator; if hydra ted,
replace. Recalibrate
balance. Reanalyze QCCS
and all affected samples.
Analyze a second sample
in triplicate. Check for
vacuum in desiccator. Re-
calibrate balance. Reana-
lyze the batch.
No correction.
(continued)
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Page 6 of 18
TabU 2-2. Continued
Parameter
Procedure
Control Limits
Corrective Action
Specific Surface
(continued)
pH
Reagent Blank Analysis
(continue 3T
Blanks show residual EGME
at end of equilibrium peroid.
Calibrate pH meter for the
range of pH expected in the
soil (usually pH = 4 and pH
= 7 standards). Analyze a
QCCS immediately after
calibration and after
analyzing every 10 or fewer
samples.
Reagent Blank Analysis
Analyze one blank of each
suspension solution.
The value of the QCCS must
be 4.00 * 0.05.
The value should be between
pH - 4.5 and 7.5.
Determine if EGME reagent
is old or otherwise
contaminated. Purchase
new reagent and reanalyze
the batch.
Recalibrate pH meter and
reanalyze fresh QCCS.
Check wiring, static
electricity, and solution
level in electrode, then
reanalyze fresh QCCS.
Replace electrode or pH
meter, then reanalyze fresh
QCCS.
Determine source of con-
tamination. Prepare new
solutions for reanalysis of
batch.
Cation Exchange
Capacity
(titration)
Laboratory Triplicate
Analysis
Analyze two additional
portions of one sample in
every batch.
Calibration and
Standardization For
ijstillation/Titration Method
Acid for titration must be
restandardized weekly.
i
Calibrate pH meter (titrator)
for range of pH expected in
the titration (end point pH =
4.60). Analyze QCCS
immediately after calibration
and after every 10 or fewer
samples.
Calculate instrumental
detection limit based upon a
minimum titration, i.e.,
smallest possible volume,
and normality of acid.
Precision should be ±0.10
units.
Normality of acid changes
more than 5 percent.
The value of the pH QCCS
must be 4.00 ± 0.05.
Instrumental detection limit
must not exceed the contract
required detection limit
(CRDL).
Analyze a second sample
in triplicate. Check for
contamination in the
suspension solution.
Prepare new solutions for
reanalysis of batch.
Prepare new solution.
Recalibrate pH meter and
reanalyze fresh QCCS.
Check wiring, static elec-
tricity, and solution level in
electrode, then reanalyze
fresh QCCS.
Replace electrode or pH
meter, then reanalyze fresh
QCCS.
Use a more dilute titrant.
(continued)
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Table 2-2. Continued
Parameter
Procedure
Control Limits
Corrective Action
Cation Exchange
Capacity (FIA)
Calibration and
Cation Exchange
Capacity (both)
Determine instrumental
detection limit.
Analyze a detection limit QC
sample.
One calibration blank ("0"
mg/L standard) and three
reagent blanks (reagents
carried through the analytical
procedure) per analytical
batch.
QCCS must be run every 10
or fewer samples if flow
injection analysis is used.
Laboratory Duplicate
Analysis
Analyze a second portion of
one sample in each batch for
each saturating solution.
Matrix Spike Sample Analysis
One spike is required for
each analytical batch. Add
standard solution of NH.CI
or (NHJ.SO. at a level
approximately equal to the
endogenous level, or 10
times the instrumental
detection limit, whichever is
greater. Samples for flow
injection analysis may be
split and the spike added to
one split. The distillation/
titration method requires
that a duplicate sample be
extracted, then spiked for
analysis.
Instrumental detection limit
must not exceed the CRDL.
Value must be within 20% of
the theoretical concentration.
Blank is less than the CRDL.
Blank exceeds the CRDL
Measure each CEC and plot
the results on a control
chart. Develop 99% and 95%
confidence limits. Required
precision is within 10%.
Precision should be within
10% RSD.
Calculate the percent
recovery. Acceptable range
is 100 i 15%.
Check for possible con-
tamination. Optimize
instrumentation, e.g.,
wavelength.
Identify and correct
problem. Acceptable result
must be obtained prior to
sample analysis.
No correction.
Investigate and eliminate
source of contamination,
then reanalyze all samples
associated with the high
blanks.
Recalibrate. Analyze a
second QCCS ana all
samples bracketed by the
affected QCCS.
Analyze a second sample
in duplicate. Check for
contamination, e.g.,
atmospheric NH.* or CO,.
Recalibrate the balance,
sample diluter (FIA), or
titrator. Reanalyze the
batch.
Repeat on two additional
samples. If either or both
are outside the control
limits, analyze the batch
by the method of standard
additions.
(continued)
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Page 8 of 18
Table 2-2. Continued
Parameter
Procedure
Control Limits
Corrective Action
Metals - Na, K.
Ca, Mg, Fe, and
Al by AAS and
ICPES.
ition and
ardization Sample
Calibrate the spectrometer
as required in the analytical
method. Analyze a QCCS
immediately after calibration
and after analysis of every
10 or fewer samples.
Verify calibration linearity.
Determine linear dynamic
range.
Determine the instrumental
detection limits.
Analyze a detection limit QC
sample.
One calibration blank CO"
mg/L standard) and one
reagent blank (any necessary
reagents carried through the
analytical procedure) per
analytical batch.
Matrix Spike Sample Analysis
To one solution in each
batch, add standard solution
of analyte at a level
approximately equal to the
endogenous level or 10 times
the instrumental detection
limits, whichever is greater.
Check recovery in each
matrix.
Calculate the QCCS value
from calibration curve and
plot result on a control chart.
Develop the 98% and 95%
confidence limit (warning
and control). Acceptable
range is ±10%.
Linearity as determined by a
least squares fit should not
be less than 0.99.
Instrumental detection limits
must not exceed the CRDL
for each element.
Value must be within 20% of
the theoretical concentration.
Blank is less than the
CRDL
Blank exceeds the CRDL.
Calculate the percent
recovery. Acceptable
recovery is 100 ± 15%.
Recalibrate instrument.
Prepare new stock and
calibration standards if
necessary. Analyze a
second QCCS and all
samples bracketed by the
affected QCCS.
Check calibration stan-
dards to see if properly
prepared. Prepare new
stock and calibration
standards, if necessary,
and recalibrate. Follow
instrument manufacturer's
troubleshooting
procedures.
Check for possible con-
tamination. Optimize
instrumentation, e.g.,
wavelength, burner or torch
position, oxidant and fuel
pressures, nebulizer flow
rate, integrity of impact
bead or spoiler, optical
alignment.
Identify and correct
problem. Acceptable result
must be obtained prior to
sample analysis.
No correction.
Investigate and eliminate
source of contamination,
then reanalyze all samples
associated with the high
blank.
Repeat on two additional
samples. If either or both
are outside the control
limits, analyze batch by
the method of standard
additions.
(continued)
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Page 9 of 18
Table 2-2. Continued
Parameter
Procedure
Control Limits
Corrective Action
Metals - Na, K,
Ca, Mg, Fe, and
Al by AAS and
ICPES.
(continued)
Exchangeable
Acidity -
BaCI/TEA. KCI
Laboratory Duplicate
Analysis
Analyze a second portion of
one sample in each batch for
each analyte.
Standardization
Trie solutions used for
titration must be
restandardized weekly.
Calculate instrumental
detection limit, based upon a
minimum titration, i.e.,
smallest possible volume,
and normality of titrants.
Precision should be within
10% BSD.
Normality of solution
changes more than 5%.
Contract-required
instrumental detection limits
must not be exceeded.
Analyze a second sample
in duplicate. Recalibrate
balance, repipet, and
sample diluter. Check for
source of contamination.
Reanalyze the batch.
Prepare new solution.
Use more dilute titrants.
Sulfate and
Nitrate
Analyze a second portion of
one sample in each batch for
each method.
Reagent Blank Analysis
Three reagent blanks per
batch are required for each
exchangeable acidity
method.
alteration and QA
alteration Sample Analysis
Precision should be within
10% RSD.
Calibrate as required in the
analytical methods. Analyze
a QCCS immediately after
calibration and after analysis
of every 10 or fewer
samples.
Verify calibration linearity.
Determine linear dynamic
range.
Blanks for KCI method are
equal to or less than twice
the CRDL.
Blanks for BaCI,-TEA method
should have a %RSD
Calculate the QCCS value
from the calibration curve
and plot result on a control
chart. Develop the 99% and
95% confidence limits
(warning and control).
Acceptable range is 15%.
Linearity as determined by a
least squares fit should not
be less than 0.99.
Analyze another sample in
duplicate. Determine
source of difficulty, e.g.,
reduce normality of titrant,
replace electrode, or
recalibrate titrator.
Reanalyze the batch.
Determine source of con-
tamination. Eliminate the
problem then reanalyze
samples associated with
the high blank(s).
Determine and eliminate
source of variation, then
reanalyze the batch.
Recalibrate instrument.
Prepare new stock and
calibration standards, if
necessary. Analyze a
second QCCS and all
samples bracketed by the
affected QCCS.
Check calibration
standards to see if
properly prepared. Prepare
new stock and calibration
standards, if necessary,
and recalibrate. Follow
Instrument manufacturer's
troubleshooting
procedures.
(continued)
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Section 2
Revision 2
Date: 12/86
Page 10 of 18
Table 2-2. Continued
Parameter
Procedure
Control Limits
Corrective Action
Sulfate and
Nitrate
(continued)
Total S, C, N
Determine instrumental
detection limits.
Resolution Check
Once per analytical run (day)
check resolution of the anion
separator column by
analyzing a standard
containing SO.1- NO.1- and
NO/ in equal 1-mg/L
concentrations. Set
instrument for a nearly
fullscate response on the
most sensitive range used.
§ alteration and Reagent
lank Analysis
One calibration blank ("0"
mg/L standard) and one
reagent blank (necessary
reagents carried through the
analytical procedure) per
analytical batch.
Matrix Spike Sample Analysis
To one sample in each
batch, add standard solution
of analyte at a level
approximately equal to the
endogenous level or 10 times
the instrumental detection
limit, whichever is greater.
Laboratory Duplicate
Analysis
Analyze a second portion of
one sample in each batch for
each extraction procedure.
Caj
Ci
libration and
libration Sample Analysis
Calibrate and standardize
induction furnace and titrator
as described in method and
instrument manual. Analyze
QCCS immediately after
calibration and after analysis
of every 10 or fewer
samples.
Instrumental detection limits
must not exceed the CRDL.
Resolution must exceed 60%.
Blank is equal to or less
than the CRDL
Blank exceeds the CRDL.
Calculate the percent
recovery. Acceptable range
is 100 i 15%.
Precision should be within
5%RSD.
Measure analyte and plot
result on a control chart.
Develop the 99% and 95%
confidence limits (control
and warning). Precision
required is 10%.
Check for possible
contamination. Optimize
instrumentation.
Clean or replace anion
separator column, then
repeat calibration and
resolution check.
No correction.
Investigate and eliminate
source of contamination,
then reanalyze all samples
associated with the high
blank.
Repeat on two additional
samples. If possible,
determine and eliminate
the source of the inter-
ference, then repeat
analyses. If either or both
are outside the control
limits, analyze the batch
by the method of standard
additions.
Analyze a second sample
in duplicate. Recalibrate
balance, repipet, and sam-
ple diluter. Check for
source of contamination.
Reanalyze the batch.
Recalibrate and then
analyze a second QCCS
and all samples bracketed
by the affected QCCS.
(continued)
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Revision 2
Date: 12/86
Page 11 of 18
Tabl«2-2. Continued
Parameter
Procedure
Control Limits
Corrective Action
Total S. C. N
(continued)
Inorganic
Carbon
Verify calibration linearity.
Determine linear dynamic
range.
Linearity as determined by a
least squares fit should not
be less than 0.99.
Determine instrumental
detection limits.
Calibration Blank Analysis
Analyze one calibration blank
per batch.
Matrix Spike Sample Analysis
To one sample per batch
add a standard amount of
analyte at the endogenous
level or 10 times instrumental
limit, whichever is greater.
Laboratory Duplicate
Analysis
Analyze a second portion of
one sample in every batch
for each procedure.
Calibration and QA
Calibration Sample Analysis
Calibrate as required in
analytical methods. Analyze
a QCCS immediately after
calibration and after analysis
of every 10 or fewer
samples.
Instrumental detection limits
must not exceed the CRDL.
Blank is less than the CRDL.
Blank exceeds the CRDL
Calculate the percent
recovery. Acceptable range
is 100 i 15%.
Precision should be within
10% RSD.
Calculate the QCCS value
from the calibration curve
and plot result on a control
chart. Develop the 99% and
95% confidence limits
(control and warning).
Acceptable range is 15%
RSD.
Check calibration
standards to see if
properly prepared. Prepare
new stock and calibration
standards, if necessary,
recalibrate. Follow instru-
ment manufacturer's
troubleshooting
procedures.
Check for possible
contamination, e.g., purity
of gas. Optimize
instrumentation.
No correction.
Eliminate source of
contamination, then
reanalyze all samples
associated with high
blank.
Repeat on two additional
samples. If possible,
determine and eliminate
the source of the
interference, then repeat
analyses. If either or both
are outside the control
limits, analyze the batch
by the method of standard
additions.
Analyze a second sample
in duplicate. Increase
sample size, e.g., use two
combustion boats.
Decrease particle size to
pass a finer mesh. Sample
may be inhomogeneous.
Check for source of
contamination. Recalibrate
the instrument, then
reanalyze the batch.
Recalibrate instrument.
Prepare new stock and
calibration standards, if
necessary. Analyze a
second QCCS.
(continued)
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Revision 2
Date: 12/86
Page 12 of 18
Tablt 2-2. Continued
Parameter
Procedure
Control Limits
Corrective Action
Inorganic
Carbon
(continued)
Verify calibration linearity.
Determine linear dynamic
range.
Determine instrumental
detection limit.
Calibration Blank Analysis
Analyze one calibration blank
per batch.
Laboratory Duplicate
Analysis
Analyze a second portion of
one sample per batch.
Matrix Spike Sample Analysis
To one sample in each
batch, add analyte at a level
approximately equal to the
endogenous level or 10 times
the instrumental detection
limit, whichever is greater.
Linearity as determined by a
least squares fit should not
be less than 0.89.
Instrument detection limit
must not exceed CRDL.
Blank is equal to or less
than the CRDL
Blank exceeds the CRDL
Precision should be within
15% RSD.
Calculate the percent
recovery. Acceptable range
is 100 ± 15%.
Check wonting standards
to see if properly prepared.
Prepare new stock and
calibration standards, If
necessary, and recalibrate.
Check for possible
contamination. Optimize
instrumentation.
No correction.
Investigate and eliminate
source of contamination,
then reanalyze all samples
associated with the high
blank.
Analyze a second sample
in duplicate. Recalibrate
balance. Sample may be
inhomogeneous. Check for
source of contamination.
Reanalyze the batch.
Repeat on two additional
samples. If possible,
determine and eliminate
the source of the
interference, then repeat
analyses. If either or both
are outside the control
limits, analyze the batch
by the method of standard
additions.
limits, some procedures require that the matrix,
i.e., extracting or saturating solutions, be
prepared from high purity chemicals.
2.6.2 Calibration Blank
Analyze one calibration blank per
batch, immediately after the initial calibration,
to check for baseline drift. The calibration
blank is defined as a "0" mg/L standard and
contains only the matrix of the calibration
standards. The observed concentration of the
calibration blank must be less than or equal
to the detection limit. If it is not, rezero the
instrument and recheck the calibration.
2.6.3 Quality Control Calibration
Samples (QCCS)
Immediately after standardization of an
instrument, analyze a QCCS containing the
analyte of interest at a concentration in the
midcalibration range. QCCS may be obtained
commercially or may be prepared by the
analyst from a source which is independent of
the calibration standards.
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Section 2
Revision 2
Date: 12/86
Page 13 of 18
The QCCS is analyzed to verify the
calibration curve prior to any sample analysis,
after every 10 samples, and after the last
sample.
The observed value for the QCCS should
be corrected for the calibration blank. Plot the
observed concentration for the QCCS on a
control chart and develop 99 percent and 95
percent confidence intervals. The 99 percent
confidence interval must not differ from the
theoretical value by more than the limits given
in Table 2-3. A value outside the 99 percent
confidence interval is unacceptable. When an
unacceptable value for the QCCS is obtained,
recalibrate the instrument and reanalyze all
samples up to the last acceptable QCCS.
Table 2-3. Maximum Control Limit* for QC Sample*
Parameter
Maximum Control Limit for QC Sam-
ple (% Deviation from
Theoretical Concentration of
QC Sample)
Particle Size
PH
Total C
Inorganic C
Total N
Total S
CEC
Na*
1C
Mg'*
Ca"
AT
Fe"
NO,-
so.1-
S04"- adsorption
Specific Surface
*
± 0.1 unit
±10%
±15%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
±10%
± 5%
± 5%
± 5%
±10%
'Refer to Section 4.12, Particle-Size Analysis.
After each day of analysis, update the
control charts. Calculate cumulative means
and new warning and control limits, i.e., 95
percent and 99 percent confidence intervals,
respectively. Bias for a given analysis is
indicated by at least seven successive points
on one side of the cumulative mean. If bias
is indicated, analysis must be stopped until
an explanation is found.
The same QCCS must be used to esta-
blish all values on a given control chart to
ensure continuity.
2.6.4 Detect/on Limit QC Samples
Analyze one detection limit QC sample
per batch. This is a low-level QC sample that
contains the analyte of interest at a concentra-
tion two to three times above the required
detection limit. The purpose of the detection
limit QC sample is to eliminate the necessity
of formally determining the detection limit
on a daily basis. The measured value must
be within 20 percent of the theoretical
concentration. If it is not, the problem must
be identified and corrected, and an acceptable
result must be obtained prior to sample
analysis.
2.6.5 Reagent Blank
For methods that require sample
preparation, prepare and analyze a reagent
blank for each group of samples processed.
A reagent blank is defined as a sample com-
posed of all the reagents, in the same quanti-
ties, used in preparing an actual sample for
analysis. The reagent blank undergoes the
same digestion and extraction procedures as
an actual sample. The concentration of the
reagent blank must be less than or equal to
the detection limit. If the concentration
exceeds this limit, the source of contamination
must be investigated and eliminated. A new
reagent blank is then prepared and analyzed,
and the same criteria are applied. All samples
associated with the "high" blank must be
reprocessed and reanalyzed after the contami-
nation has been eliminated.
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2.6.6 Preliminary Sample Analysis 2.6.7.2 Solid Samples--
Approximately seven samples and a
reagent blank are analyzed prior to matrix
spike and duplicate analyses so that approxi-
mate endogenous sample concentrations may
be determined.
2.6.7 Matrix Spike Analysis
Prepare one matrix spike sample for
each procedure, as specified.
2.6.7.1 Liquid Samples-
For liquid samples, a matrix spike sam-
ple is prepared by spiking an aliquot of a
solution with a known quantity of analyte prior
to analysis. The spike concentration must be
approximately equal to the endogenous level or
10 times the detection limit, whichever is
larger. Also, the volume of the added spike
must be negligible, i.e., less than or equal to
0.01 of the sample aliquot volume. The spike
recovery must be within 100 ± 15 percent to be
acceptable.
If the recovery is not acceptable, two
additional, different samples must be spiked
with the analyte in question and must be
analyzed. If the recovery for one or both
samples is not within 100 ± 15 percent, the
entire batch must be analyzed for the analyte
in question by the method of standard addi-
tions. (Refer to Section 8.5 in Appendix A.)
The method of standard additions is per-
formed by analyzing the sample, analyzing the
sample plus a spike at about the endogenous
level, and analyzing the sample plus a spike at
about twice the endogenous level. The concen-
tration of the matrix spike sample must not
exceed the linear range of the instrument. If
it does, the spiked sample must be diluted
before analysis. The % spike recovery is
calculated as follows:
% spike recovery =
r value of sample
plus spike
value of unspikeo\
sample
Matrix spikes for solid samples, e.g., for
analysis of total carbon and total nitrogen, are
prepared by adding a known weight of materi-
al containing the analyte of interest to a sam-
ple of known weight. The spike concentration
should be twice the endogenous level or 10
times the detection limit, whichever is larger.
The concentration of the matrix spike must not
exceed the linear range of the instrument.
Although it will not be negligible, the weight of
the spike material should be considered negli-
gible for the purposes of calculation.
The spike recovery must be within 100 t
15 percent to be acceptable. If the recovery is
not acceptable, two additional, different sam-
ples must be spiked with the analyte in ques-
tion and must be analyzed. If the recovery for
one or both samples is not within 100 t 15
percent, the entire batch must be analyzed for
that analyte by the method of standard addi-
tions.
2.6.8 Duplicate Sample Analysis
Prepare and analyze one sample per
batch in duplicate for each parameter. (Some
procedures require triplicate analysis. Refer to
specific method.)
Calculate the percent relative standard
deviation (%RSD) as follows:
%RSD
s
VlOO where 6 =
n'1
1/2
value of spike added
'(100)
The relative standard deviation is plotted
on a control chart, and 99 percent and 95
percent confidence intervals are established.
These confidence intervals represent control
and warning limits, respectively. Initial control
limits are set at the precision levels given in
Table 2-4. If duplicate values fall outside the
control limits, an explanation must be sought,
e.g., instrument malfunction or calibration drift.
A second, different sample must then be
analyzed in duplicate. No further samples
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Table 2-4. Required Detection Limits, Expected Range*, and Intralaboratory Relative Precision Goal
Calculated
Parameter Matrix Reporting Units
Particle size —
pH
Tntal P
Inorganic C —
Total N —
Total
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and NO3~. If the resolution does not exceed 60
percent, the column should be replaced, and
the resolution test should be repeated.
2.6.10 Continuing Sample
Analysis
The remaining samples are analyzed if
the detection limit QC sample, QCCS, reagent
blank, matrix spike, and duplicate samples are
within the required limits. After every 10 or
fewer samples and after the last sample, a
QCCS is analyzed to periodically verify the
calibration curve. If the measured value of
the QCCS differs from the theoretical value by
more than the limits given in Table 2-3, the
instrument must be restandardized, and the
previous 10 samples must be reanalyzed.
2.7 Instrumental Detection
Limits
Instrumental detection limits (IDLs) are
determined and recorded monthly for each
parameter except pH. For this study, the
detection limit is defined as three times the
standard deviation of 10 nonconsecutive rep-
licate calibration blank analyses run on sepa-
rate days. In some analyses, such as ion
chromatography, a signal may or may not be
obtained for a blank analysis. If a signal is
not obtained for a blank analysis, the instru-
mental detection limit is defined as three times
the standard deviation of 10 nonconsecutive
replicate analyses of a standard whose con-
centration is four times the lesser of the
actual detection limit or the required detection
limit.
2.8 Reagent Blank Correction
for Spectrometric and Ion
Chromatographic
Procedures
For all spectrometric and ion Chromato-
graphic procedures presented in this manual,
the equations presented in the calculations
subsections assume that the concentration of
the analyte in solution has been corrected for
the reagent blank. The reagent blank, com-
posed of all the reagents in the same quanti-
ties used for actual samples, undergoes the
same manipulations as actual samples and
therefore should reflect any analyte contamina-
tion from the sample matrix or analytical
procedure. Specifically, the actual (corrected)
solution concentration is equal to the analyte
concentration in the sample solution minus the
analyte concentration in the reagent blank.
2.9 Data Reporting
An index of the data forms used by the
analytical laboratory is provided in Table 2-5.
The data forms are in Appendix C. Record the
raw data on forms 115, 116, 303b, 306, and
308. Summarize pH, moisture, and particle
size analysis results on forms 103a and 103b.
Summarize data that are corrected both for
blanks and dilutions on the 200-series forms.
Annotate the data by using the data qualifiers
listed in Table 2-6, if applicable. Results should
be reported to the same number of decimal
places as listed in Table 2-7. However, no
more than four significant figures should be
reported. Forms 109 through 114 contain
quality control data. After a form is complet-
ed, the laboratory manager must sign it to
indicate that he or she has reviewed the data
and that the samples were analyzed exactly
as described in the procedure.
Document all deviations from the manual.
All original raw data such as data system
printouts, chromatograms, notebook, individual
data sheets, QC charts, and standard prepara-
tion data should be retained.
2.10 Sample Handling For
Mineralogical Analyses
The preparation laboratory splits a
500-g aliquot from each bulk soil sample
chosen for analysis. This is stored in a
500-mL high-density polyethylene bottle. A
mineralogical batch of 26 samples consists of
20 soil samples, 3 duplicates, and 3 audit
samples.
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Page 17 of 18
Table 2-5. Index of Data Forms
Form Number
Title
102
103 (a.b)
109 (a,b,c)
110 (a.b.c)
111 (a through i)
112 (a through h)
113
114 (a.b.c)
115 (a through e)
116 (a through h)
204 (a,b.c,d)
205
206
207
208
303b
306
308
Shipping Form
Summary of pH and Particle Size Results
Quality Control: Detection Limits
Quality Control: Matrix Spikes
Quality Control: Replicates
Quality Control: Blanks and QCCs
Quality Control: Ion Chromatograph Resolution Test
Quality Control: Standard Additions
Sample Weight in Grams
Dilution Factors and Dilution Blanks; Solution Concentration; liter and Normality
Summary of Exchangeable Bases and CEC Results - Blank Corrected
Summary of Iron- and Aluminum-Extraction Data - Blank Corrected
Summary of Extractable Nitrate and Sulfate, Exchangeable Acidity, and Exchangeable
Aluminum - Blank Corrected
Summary of Sulfate-Adsorption Isotherm Data - Blank Corrected
Summary of C, N, S, and Specific-Surface Results - Blank Corrected
Summary of Particle Size Analysis Raw Data
Summary of BACL, Exchangeable Acidity Raw Data
Summary of C, N, S, and Specific Surface Raw Data
2.11 Laboratory Procedures
For Mineralogical
Analyses
Procedures for mineralogical analyses
are detailed in sections 17, 18, and 19 of this
manual. Table 2-8 summarizes the parameters
determined and the corresponding analytical
techniques. QC procedures are indicated in
the appropriate method description.
2.12 References
American Society for Testing and Materials.
1984. Annual Book of ASTM Standards,
Vol. 11.01, Standard Specification for
Reagent Water, D1193-77 (reapproved
1983). ASTM, Philadelphia, Pennsylvania.
Bartz, J. K., D. S. Coffey, and L J. Blume.
1987a. Preparation Laboratory Manual
for the Direct/Delayed Response Project
Soil Survey. U.S. Environmental Protec-
tion Agency, Las Vegas, Nevada. Appen-
dix A In: Direct/Delayed Response
Project Southern Blue Ridge Province
Field Sampling Report: Vol. II Sample
Preparation. U.S. Environmental Pro-
tection Agency.
Bartz, J. K., S. K. Grouse, M. L Papp, K. A.
Cappo, G. A. Raab, L. J. Blume, M. A.
Stapanian, F. C. Garner, and D. S. Coffey.
1987b. Direct/Delayed Response Project:
Quality Assurance Plan for Soil Sampling,
Preparation, and Analysis. U. S. Environ-
mental Protection Agency, Las Vegas,
Nevada.
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Table 2-6. Laboratory/Field Data Qualifier*
Data qualifiers
Indicates
Table 2-8. Mlneraloglcal Parameters and
Corresponding Analytical Techniques
A Instrument unstable.
B Redone, first reading not acceptable.
F Result outside criteria vt ith consent
of QA manager.
G Result obtained from method of
standard additions.
J Result not available; insufficient
sample volume shipped to
laboratory.
L Result not available because of
interference.
M Result not available; sample lost or
destroyed by laboratory.
N Result outside QA criteria.
P Result outside criteria, but
insufficient volume for reanalysis.
R Result from reanalysis.
S Contamination suspected.
T Container broken.
U Result not required by procedure;
unnecessary.
X No sample.
Y Available for miscellaneous com-
ments.
Z Result from approved alternative
method.
Parameter
Method
Mineralogy of <2-mm and
<0.002-mm fractions
Elemental analysis of bulk
sample and of clay
fraction
Mineralogy of heavy mineral
fraction
Morphological features of
samples
X-ray diffraction
spectrometry
Wavelength-dispersive
X-ray spectrometry
Scanning electron
microscopy/energy
dispersive X-ray
spectrometry
Scanning electron
microscopy/energy
dispersive X-ray
spectrometry
Table 2-7. Ust of Decimal-Place Reporting
Requirements
Number of Decimal Places
Parameter in Reported Results*
Moisture content
Particle size
PH
Total C
Inorganic C
Total N
Total S
CEC
Na
k . ~,
Mg?T
Ci?r"
At?£
Fflr
NCwT
SO?" adsorption
Exchangeable acidity
Specific surface
3
1
2
3
3
3
2
3
3
3
3
3
3
3
2
2
3
2
4
* Report to a maximum of four decimal places.
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3 Moisture Content
3.1 Scope and Application
Moisture will be determined in duplicate
on all samples. The average percent moisture
will be used to convert all results to an oven-
dry basis and, if specified in a procedure, to
calculate the weight of sample equivalent to a
given weight of oven-dried soil.
3.2 Summary of Method
Replicates are weighed, are dried in an
oven, and are reweighed. The drying is con-
tinued until the sample reaches a constant
weight. By convention, the moisture content of
soil is expressed as a weight percentage in
terms of the water associated with the oven-
dried soil weight. The weight of wet soil is
undesirable as the basis for calculation be-
cause it varies as the moisture content
changes (see Brady, 1974).
3.3 Interferences
Use forceps or finger cots to handle
weighing containers to avoid adding deposits
of salts and oil.
3.4 Safety
Use forceps or heat-resistant gloves to
remove weighing containers from a hot oven.
3.5 Apparatus and Equipment
• Balance capable of weighing ±0.01 g.
• Ovens capable of being heated to
110 °C (two each).
• Thermometers, 0 °C to 200 °C range
(two each).
• Weighing containers capable of with-
standing intermittent heating to 110 °C
and cooling to room temperature.
• Desiccator and desiccant.
3.6 Reagents and Consumable
Materials
No reagents or consumable materials
are required for this determination.
3.7 Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labo-
ratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the analytical laboratory, all samples are
kept sealed and are refrigerated at 4 °C when
not being used.
3.8 Calibration and
Standardization
Check thermometers periodically to en-
sure that they are measuring temperature
accurately. The ovens should be monitored to
ensure that temperature fluctuation does not
exceed ±5 °C.
3.9 Quality Control
QC procedures are specified in Section
2.6. Run at least one sample from each batch
in triplicate. In addition to the sample that
is run in triplicate, a hydrated laboratory chem-
ical that loses a known amount of water at a
temperature slightly below the oven tempera-
ture may be run as a QCCS.
3.10 Procedure
1. Allow each oven to equilibrate at the
required temperature ±5 °C for at
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Page 2 of 2
least 24 hours. Heat the ovens used
to dry mineral soils to 105 °C; heat
the oven used to dry organic soils to
60 °C.
2. Weigh two 10-g replicates of each
sample accurately to ±0.01 g and
record the air-dry weight.
3. Dry mineral soils for 24 hours at 105
°C. Dry organic soils for 24 hours at
60 °C.
4. Allow soil to cool in a desiccator.
Weigh each replicate and record initial
oven-dry weight.
5. Dry each replicate for an additional 2
hours at the appropriate temperature:
105 °C for mineral soils or 60 °C for
organic soils.
6. Cool the soil in a desiccator. Weigh
each replicate and record the oven-dry
weight. The second value for weight
should be within 1 percent of the
initial oven-dry weight. If it is not,
repeat drying for 2-hour intervals until
oven-dry weights are within 1 percent.
NOTE: It is possible that some of the fine
silt and clay fractions may be lost
because of excessive movement of
sample to and from the oven.
3.11 Calculations
Example: If % moisture equals 3.5%, then:
% Moisture =
'wt air-dried soil - wt oven-dried soil\
wt oven-dried soil
'
(100)
air-dried soil equivalent to oven-dried
weight of soil =
(grams oven-dried soil desired)
1.000 -
moisture
100 /
(3-1)
(3-2)
10 g oven-dried soil
- .... —ii. —i _,. i S
1.000 - 0.035
10.36 g air-
dried equivalent to
10.00 g overt-dried soil
3.12 Precision and Accuracy
The %RSD of triplicate samples should
be ±5 percent. All weights should be recorded
in grams to two decimal places, ±0.01 g.
3.13 References
Blume, L J., M. L. Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. U.S.
Environmental Protection Agency, Las
Vegas, Nevada. Appendix A In: Direct/-
Delayed Response Project Southern Blue
Ridge Province Field Sampling Report:
Vol. I Field Sampling. U.S. Environmental
Protection Agency.
Brady, N. C. 1974. The Nature and
Property of Soils. Eighth Edition. Macmillan
Publishing Co., Inc., New York, New York.
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Page 1 of 6
4 Particle-Size Analysis
4.1 Scope and Application
Particle-size analysis or soil texture is
determined on the less than 2-mm fraction
from mineral horizons only. The mineral hori-
zons constitute about 88 percent of the sam-
ples. The sieve/pipet/gravimetric method
described in Soil Survey Investigations Report
No. 1 (USDA/SCS, 1984) is used. Most pre-
existing data have been determined by using
this method.
4.2 Summary of Method
Organic matter and dissolved minerals
are removed from the sample. The sand
fractions are separated from the silt and clay
fractions by a washing process. The silt and
clay are put in suspension, and then aliquots
taken from the suspension are dried. The
dried residues are then weighed. The sand
fractions are sieved, and each fraction is
weighed. The resulting gravimetric data allow
for calculation of the percentage of each
particle size.
4.3 Interferences
While the soil in suspension is settling,
the graduated cylinders containing the suspen-
sion cannot be disturbed, nor can the tempera-
ture vary. When handling weighing bottles, use
forceps, finger cots, cotton gloves, or vinyl
gloves to avoid adding weight from moisture
and from body salts and oils.
4.4 Safety
Use forceps or heat-resistant gloves to
remove weighing bottles from hot ovens. Use
waterproof gloves while handling hydrogen
peroxide. Follow standard laboratory safety
practices when handling reagents and
equipment.
4.5 Apparatus and Equipment
• Erlenmeyer flask, or other suitable
container, 250 mL or equivalent (tare
to ±0.1 mg).
• Pasteur-Chamberlain filter candles (or
equivalent), fineness "F"; store in
double-deionized (DOI) water.
• Reciprocating shaker, 120 oscillations
per minute.
• Sedimentation cylinders (1-L gradu-
ated cylinders, optional).
• Stirrer, motor-driven.
• Stirrer, hand. Fasten a circular piece
of perforated plastic to one end of a
brass rod.
• Shaw pipet rack, or equivalent.
• Pipets, 25 mL automatic (Lowy with
overflow bulb, or equivalent).
• Polyurethane foam, pipe-insulation;
constant temperature bath (±1 °C) or
temperature-controlled room (±1 °C).
• Shaker, 1.25-cm vertical and lateral
movement, and 500 oscillations per
minute, or equivalent. Unit must
accommodate a nest of sieves.
• Glass weighing bottles, 90 mL, wide-
mouth with screw caps, or equivalent,
(tare to ±0.1 mg), capable of with-
standing intermittent heating to 110 °C
and cooling to room temperature.
• Electronic analytical balance (0.1 mg
sensitivity).
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Page 2 of 6
• Set of sieves, square-mesh, woven
phosphor-bronze or stainless steel
wire cloth; U.S. Series and Tyler
Screen Scale equivalent designations
as follows:
Nominal U.S.
Opening (mm) No.
Tyler
Mesh Size
1.0
0.5
0.25
0.105
0.046
18
35
60
140
300
16
32
60
150
300
4.6
• Receiving pan, used with sieves.
• Hot plate (block digester, optional).
• Thermometer, range 10 to 50 °C.
• Evaporating dishes, or equivalent, 125
or 250 ml.
• Desiccator and desiccant.
Reagents and Consumable
Materials
• Hydrogen peroxide
percent.
• Sodium carbonate
,), 30 to 35
4.7
• Sodium hexametaphosphate (N
dispersing agent - Dissolve 35.7
grams of (NaPOg)6 and 7.94 grams of
Na2CO3 per liter of water.
• Double-deionized (DDI) water.
Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labo-
ratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
4.8 Calibration and
Standardization
Calibrate thermometers periodically to
ensure that they are measuring temperature
accurately. Temperatures of the suspensions
should vary no more than ±1 °C.
4.9 Quality Control
QC procedures are specified in Section
2.6. At least one well-characterized soil must
be used as a QCCS for each set of soils
fractionated. If the QCCS does not cover the
entire range of particle sizes (including a
minimum of 5 percent each of the sand, silt,
and clay fractions), a second well-character-
ized soil must be used to cover the missing
range. The temperature of the water in the
sedimentation cylinders must remain within
1 °C of the initial temperature.
4.10 Procedure
4.10.1 Removing Organic Matter
1. Weigh 10.00 g air-dried soil into a
tared Fleaker. For soils low in clay, it
may be necessary to double the
amount of soil in order to meet the
required precision. Doubling the
amount of soil does not require any
adjustments to the remaining steps in
this procedure.
2. Add 50 mL of DDI water followed by
5 mL of H2O2. Cover the Fleaker with
a watch glass. If a violent reaction
occurs, repeat the H2O2 treatment
periodically until no more foaming
occurs.
3. Heat the Fleaker to about 90 °C on an
electric hot plate. Add H2O2 in 5-mL
quantities at 45-minute intervals until
the organic matter is destroyed, as
determined visually. Continue heating
for about 30 minutes to remove ex-
cess H2O2.
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Page 3 of 6
NOTE: For simplicity, use block digestion
apparatus, if available, and replace
Ftoakers with block digestor tubes.
The removal of the organic matter
may require 24 to 36 hours.
4.10.2 Removing Dissolved
Mineral and Organic
Components
1. Place the Fleaker in a rack and add
about 150 ml of DDI water in a jet
strong enough to stir the sample well.
Remove solution from the suspension
with a filter-candle system. Five such
washings and filterings are usually
sufficient, except for soils that contain
much coarse gypsum; these soils
require additional treatments.
2. Remove soil that adheres to the filter
by applying gentle air pressure.
3. Dry the sample overnight in an oven
at 105 °C, cool the sample in a desic-
cator, and weigh the sample to the
nearest milligram. Use the weight of
the oven-dried, H2O2-treated sample
as the weight for calculating percent-
ages of the particle-size fractions.
4.10.3 Dispersing the Sample
Add 10 ml_ of sodium hexametaphos-
phate dispersing agent to the Fleaker that
contains the oven-dried, treated sample. Bring
the volume to approximately 200 ml. Stopper
the Fleaker and shake overnight on a horizon-
tal reciprocating shaker at 120 oscillations per
minute.
4.10.4 Separating Sand from Silt
and Clay
1. Place the 300-mesh sieve on top of
the sedimentation cylinder. A clamp
and ring stand may be used to hold
the sieve in place. Wash the dis-
persed sample onto the sieve with
DDI water. Avoid using jets of wa-
ter because they may break the fine
mesh of the sieve. Silt and clay will
pass through the sieve into the cylin-
der. The sand and some coarse silt
will remain on the sieve. It is impor-
tant to wash all particles of less than
0.02-mm diameter through the sieve.
Gently tapping the sieve clamp with
the side of the hand will facilitate
sieving.
2. Continue washing the sand until the
suspension volume in the cylinder is
about 800 ml.
3. Remove the sieve from the cylinder.
Wash the sand into an evaporating
dish with DDI water. Dry the sand
overnight at 105 °C. Continue at
4.10.6 for fractionation of the sand.
4. Dilute the silt and clay suspension in
the cylinder to 1.00 L with DDI water.
Cover the cylinder with a watch glass.
4.10.5 Pipetting
All pipetting is performed in a location
free from drafts and temperature fluctuations.
A temperature-controlled room, constant-
temperature water bath, or foam insulation
may be used.
1. Allow 12 to 24 hours for the tempera-
ture of suspension to equilibrate.
2. Stir the material in the sedimentation
cylinder for 6 minutes with the motor-
driven stirrer. Stir 8 minutes if sus-
pension has been standing for more
than 16 hours.
If stoppers of adequate size are avail-
able, it is preferable to stopper the
cylinder, invert, and swirl. Repeat this
procedure at least six times. Inspect
the bottom and sides of the cylinder
to ensure that fine particles are not
adhering to the glass walls of the
cylinder.
3. Remove the stirrer and either (1) cover
the cylinder with a length of polyuret-
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Page 4 of 6
hane foam pipe-insulation, (2) im-
merse the cylinder in a constant-tem-
perature water bath, or (3) place the
cylinder in a temperature-controlled
room.
4. Stir the suspension for 30 seconds
with a hand stirrer; use an up-and-
down motion. Record the time when
the stirring is complete. Do not move,
stir, or otherwise disturb the cylinder
from this point until all pipetting has
been completed.
(Alternative Procedure: At time zero,
a 25-mL aliquot may be taken as de-
scribed in steps 7 through 10 of this
section. This aliquot represents all
silts and clays. By subtracting the
values obtained in Section 4.11 for fine
silt and clay, the result is a more
direct quantitation of the coarse silt
fraction. If this alternative procedure
is used, the resulting data must be
tagged with a "Z" when reported on
the data summary forms.)
5. Take the temperature of the solution
in the cylinder by gently lowering a
thermometer 5 cm into the suspen-
sion. Support the thermometer with a
clamp to reduce disturbance to the
suspension.
6. Use the temperature and Table 4-1 to
determine the settling time required
for the <0.02-mm fraction, e.g., at 27
°C allow 4 minutes, 4 seconds.
7. About 60 seconds before the sedi-
mentation time has elapsed, slowly
lower the Lowy automatic pipet 10 cm
into the suspension. (A 25-mL volu-
metric pipet premarked for a 10-cm
depth and clamped firmly in place on
a stand may be used.)
8. At the appropriate time, slowly
(allow about 12 seconds) fill the pipet.
Carefully remove it from the suspen-
sion.
9. Wipe clean the outside of the pipet
and empty the contents into a tared,
drying container such as a 90-mL
widemouth bottle. Rinse the pipet
Table 4-1. Sedimentation times* for Particle* of less
than 0.002, less than 0.005, and less
than 0.002 mm Diameter Settling Through
Water for a Depth of 10 cm
Settling time with indicated
particle diameter
Temperature <0.002 mm <0.005 mm <0.02 mm
°c
20
21
22
23
24
25
26
27
28
29
30
31
hr.
8
7
7
7
7
7
6
6
6
6
6
6
min hr.
0 1
49 1
38 1
27 1
17 1
7 1
57 1
48 1
39 1
31 1
22 1
14 1
min
17
15
13
11
10
8
7
5
4
3
1
0
mir
4
4
4
4
4
4
4
4
4
3
3
3
.:sec.
48
41
35
28
22
16
10
4
0
55
49
44
* Values calculated from Stokes' equations, assuming a
particle density of 2.60 g/cm. This figure for particle
density is arbitrary and has been chosen to satisfy
simultaneously the two definitions of the clay fraction,
i.e., particles that have an effective diameter of 0.002
mm and particles that have a settling velocity of 10 cm
in 8 hours at 20 °C.
into the bottle once with DDI water
(add the rinse water to the contents
of the bottle.
10. Dry the bottle and contents in an oven
overnight at 105 °C. Cool in a desic-
cator over phosphorus pentoxide
(PA). Weigh.
11. Repeat steps 5 through 10 for the
<0.002-mm fraction. The <0.002-mm
fraction may be pipetted at a time
between 4.5 and 8 hours depending
on the temperature and the table (4-1
or 4-2) used. Using Table 4-1 and a
depth of 10 cm is the most desirable
and easiest method.
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Section 4
Revision 2
Date: 12/86
Page 5 of 6
Table 4-2.* Sedimentation Time* and Pipetting Depths for Particles of <0.002 mm
Sedimentation time
Temperature C°
4 hr. 30 min.
5hr.
5 hr. 30 min.
6 hr. 30 min.
20.0
20.3
20.5
20.7
21.0
21.3
21.5
21.7
22.0
22.3
22.5
22.7
23.0
23.3
23.5
23.7
24.0
24.3
24.5
24.7
25.0
25.3
25.5
25.7
26.0
26.3
26.5
26.7
27.0
27.3
27.5
27.7
28.0
28.3
28.5
28.7
29.0
29.3
29.5
29.7
30.0
5.79 cm
5.81
5.86
5.89
5.93
5.97
6.01
6.04
6.09
6.13
6.15
6.18
6.22
6.27
6.29
6.33
6.37
6.40
6.43
6.45
6.51
6.56
6.58
6.61
6.66
6.69
6.72
6.76
6.81
6.85
6.87
6.91
6.97
7.01
7.04
7.07
7.12
7.16
7.19
7.22
7.27
6.44 cm
6.48
6.52
6.55
6.59
6.64
6.68
6.72
6.75
6.80
6.83
6.86
6.91
6.96
6.98
7.04
7.08
7.12
7.15
7.18
7.24
7.28
7.31
7.35
7.40
7.44
7.47
7.51
7.56
7.61
7.64
7.68
7.74
7.79
7.82
7.86
7.91
7.95
7.99
8.02
8.08
7.08 cm
7.13
7.17
7.20
7.25
7.30
7.34
7.39
7.43
7.49
7.51
7.55
7.60
7.66
7.68
7.74
7.78
7.83
7.86
7.89
7.96
8.01
8.04
8.08
8.14
8.18
8.22
8.26
8.32
8.37
8.40
8.44
8.51
8.57
8.61
8.65
8.70
8.75
8.79
8.82
8.88
8.37 cm
8.43
8.47
8.51
8.57
8.63
8.68
8.73
8.78
8.85
8.88
8.92
8.98
8.98
9.08
9.15
9.20
9.25
9.29
9.33
9.41
9.47
9.50
9.55
9.62
9.67
9.72
9.76
9.83
9.89
9.93
9.98
10.06
10.13
10.17
10.22
10.28
10.34
10.39
10.43
10.50
8 Table and calculations provided by Duane Mays, USDA-SCS National Soil Survey Laboratory, Lincoln, Nebraska (May,
b 1985>' 3
Assuming a particle density of 2.65 g/cm .
4.10.6 Sieving and Weighing the
Sand Fractions
Stack sieves from largest (1.0 mm) to
smallest (0.046 mm) nominal opening with the
1.0-mm sieve at the top and the receiving
panat the bottom. Transfer the dried sand to
the nest of sieves. Place sieves on a shaker
that has 1.25-cm vertical and lateral move-
ments and oscillates at 500 strokes per min-
ute, or an equivalent shaker. Shake for 3
minutes. Weigh the sand fraction that is
retained by each sieve and by the receiving
pan. Theoretically no soil should pass through
the lowest sieve (0.046 mm) into the receiving
pan. Soil that does pass the sieve is either
silt or clay, and should not be included in the
very fine sand fraction.
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Section 4
Revision 2
Date: 12/86
Page 6 of 6
4.11 Calculations
Pipetted fractions:
Percentage of pipetted fractions = (A - B)KD
where
A = oven-dry weight (g) of pipetted
fraction
B = weight correction for dispersing
agent (g) = oven-dry weight (g) of
aliquot of dispersing solution as
diluted for analysis
1,000
K =
D =
mL in pipet
100
g of H2O2-treated oven-dried
total sample
The fraction remaining when the <0.002-
mm fraction is subtracted from the <0.02-mm
fraction is the fine silt. The sum of the sand
and clay fractions (in percentage) subtracted
from 100 will equal the silt fraction as defined
by the USDA/SCS (1984). The coarse silt is
equal to the USDA silt fraction minus the fine
silt fraction.
% silt =
% clay =
% sand =
100 - (% clay + % sand) (4-1)
(A - B)KD (4-2)
(summation of percentages (4-3)
for individual sand fractions)
% of sieved
sand fractions
Calculate percent sand, silt, and clay.
Also calculate sand fraction percentages (very
fine sand [0.05 to 0.10 mm], fine sand [0.10 to
0.25 mm], medium sand [0.25 to 0.50 mm],
coarse sand [0.50 to 1.0 mm], very coarse
sand [1.0 to 2.0 mm]), and silt fraction per-
centages (fine silt [0.002 to 0.02 mm] and
coarse silt [0.02 to 0.05 mm]).
4.12 Precision and Accuracy
The required precision for values less
than 10 percent absolute is 1 percent absolute.
From 10 percent to 100 percent absolute, the
required precision starts at 10 percent relative
and tapers to 5 percent relative at 100 percent
absolute. The %RSD for replicates is 10 per-
cent or less.
4.13 References
Blume, L J., M. L Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. U.S.
Environmental Protection Agency, Las
Vegas, Nevada. Appendix A In: Direct/-
Delayed Response Project Southern Blue
Ridge Province Field Sampling Report:
Vol. I Field Sampling. U.S. Environmental
Protection Agency.
U.S. Department of Agriculture/Soil Conserva-
tion Service. 1984. Soil Survey Laborato-
ry Methods and Procedures for Collecting
Soil Samples. Soil Survey Investigations
Report No. 1, USDA U.S. Government
Printing Office, Washington, D.C.
weight [g] of fraction
on sieve (D) (4-4)
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Section 5
Revision 2
Date: 12/86
Page 1 of 3
5 Specific-Surface Determination
5.1 Scope and Application
Specific surface is determined on the
less than 2-mm material of mineral horizons
only. The mineral horizons constitute about 88
percent of the samples. Specific surface is
defined as the total surface area per unit
mass. It is usually expressed as square
meters or square centimeters per gram of soil.
Specific surface is important in evaluating soil
characteristics because it is highly correlated
with cation-exchange capacity (CEC) and with
the adsorption and desorption of numerous
chemicals such as nutrients and pollutants
(Hillel, 1980). For example, two soils with the
same percentages of sand, silt, and clay might
have extremely different measurements of CEC
and sulfate adsorption due to differences in
surface area of different clay minerals. The
differences in surface area can be determined
by comparing specific surface measurements.
5.2 Summary of Method
Many procedures are available for deter-
mination of specific surface. These methods
each involve coating the surface of the entire
sample with a monomolecular layer of a polar
liquid, such as glycerol, or an inert gas,
such as nitrogen. The method used here
employs a glycerol, ethylene glycol monoethyl
ether (EGME), to establish the monomolecular
layer, as described in Soil Survey Investiga-
tions Report No. 1 (USDA/SCS, 1984). The
amount of EGME used for each sample varies
with soil texture and is measured gravimetri-
cally.
5.3 Interferences
No specific interferences are expected
if normal laboratory technique is practiced.
The soil in the vacuum desiccators is highly
hygroscopic and will pick up moisture within
minutes of exposure to atmospheric condi-
tions. Minimum exposure time to the atmos-
phere while weighing is essential. The desic-
cators should be as close to the balances as
possible. Small but significant amounts of soil
may be lost from each sample any time the
sample is transported from the desiccator to
the balance and back again.
5.4 Safety
Normal laboratory safety practices
should be observed when handling reagents.
P2O5 is corrosive and reacts violently with
water; EGME is combustible. Both reagents
are fire hazards. Standard protective clothing
and equipment should be used when handling
these reagents.
5.5 Apparatus and Equipment
• Analytical balance, capable of measur-
ing to ±0.1 mg.
• Vacuum desiccator.
• Rubber ring, cushion for glass sur-
faces of desiccator.
• Vacuum pump, capable of reducing
pressure within the desiccator to
between 0.65 and 0.75 bar.
• Drying tube-Fill with anhydrous CaCI2
to form EGME trap; place between
vacuum desiccator and vacuum
source.
• Syringe, 1 ml_.
5.6 Reagents and Consumable
Materials
Ethylene glycol monoethyl
(EGME), reagent grade.
ether
• Phosphorus pentoxide (P2OJ, anhy-
drous.
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Section 5
Revision 2
Date: 12/86
Page 2 of 3
5.7
• CaCI2, 4- to 8-mesh, anhydrous re-
agent grade.
• N2 adsorption standards, may be
purchased from Duke Scientific Corp.,
Palo Alto, California.
Sample Collection,
Preservation, and Storage
Sample collection and preservation are
discussed in Blume et al. (1987). No preserva-
tives are added to the samples. Within 24
hours of collection, samples are delivered to
the preparation laboratory and are refrigerated
at 4 °C. If this time requirement cannot be
met, the samples are placed in a cooler after
they are collected. In the analytical laboratory,
all samples are kept sealed and are refriger-
ated at 4 °C when not being used.
5.8 Standardization and
Calibration
The analytical balance should be regular-
ly serviced by a qualified technician. The
vacuum desiccator must be checked on a
regular basis for ability to maintain a vacuum.
5.9 Quality Control
QC procedures are specified in Section
2.6. Analyze three replicates per batch. If
multiple desiccators are used, place one
replicate in each desiccator. Run three blanks
containing an amount of EGME equal to the
greatest quantity required to saturate the soil
samples. Measure and record the weight of
each blank every two to three days until the
last sample has equilibrated. These blank
values are reported on Form 112h (Appendix
C). New EGME will not produce a measurable
residue. Therefore, if the blanks are greater
than or equal to 0.001 g, obtain new EGME
and rerun all affected samples. Use the N2
adsorption standard or at least one well-
characterized soil sample as a QCCS. Ana-
lyze one QCCS per batch of 21 or fewer sam-
ples, and two QCCS per batch of 22 or more
samples. It may be desirable to use well-
characterized soils in the low, medium, and
high range as QCCS if repeatability is difficult
to attain.
5.10 Procedure
1. Dry about 4 g of <2-mm oven-dried
equivalent-weight soil in a weighing
dish for 2 days over P2O5 in a vacuum
desiccator. Weight the P2Cydried
sample to ±0.1 mg.
2. Using a 1-mL syringe, thoroughly
saturate the soil with EGME and add
5 drops EGME in excess. Record
weight of sample plus EGME. Place
the soil-EGME mixture over anhydrous
4- to 8-mesh CaCI2 in a vacuum desic-
cator. Connect the desiccator to a
vacuum source, and slowly apply
vacuum until a pressure of 0.65 to
0.75 bar is reached within the
desiccator.
3. After 24 hours of continuous vacuum,
weigh the soil-EGME mixture. Com-
pare the soil-EGME weight to the
initial weight of soil dried over P2OS.
If the difference between the two
weights is greater than 10 mg of
EGME per gram of P2O5-dried soil,
continue the desorption of EGME with
continuous vacuum and weigh the
mixture daily.
4. When the difference between the two
weights is less than 10 mg of EGME
per gram of P2Os-dried soil, reduce
the time of desorption under vacuum
to 1 hour per day. Continue weighing
the soil-EGME mixture every 24 hours.
It is not always necessary to weigh
daily for the first few days because
only very sandy soils equilibrate that
rapidly. Additionally, small but signifi-
cant amounts of soil can be tost each
time the sample is moved. Repeat
this procedure of desorption of EGME
and daily weighings until constant
weight is attained. Constant weight
is indicated when three successive
weighings are within 0.20 mg of EGME
-------
Section 5
Revision 2
Date: 12/86
Page 3 of 3
NOTE:
per gram of P2O5-dried soil or about
0.80 mg per 4-g sample. Average the
three values for use in calculating the
retention of EGME (in Equation 5-1).
Equilibration generally requires 5 to 25
days.
5.11 Calculations
Data uncorrected for blanks are calcu-
lated according to the following equations:
Retention of EGME, (mg/g) = «^
X soil wt (g) EOME - soil wt (g) P2O5 (1000)
soil wt (g)
(5-1)
Specific
surface (m2/g)
Retention of EGME (mg/g)
0.286 mg/m2 (5-2)
NOTE: The constant 0.286 is the calculated
amount of EGME (in milligrams) need-
ed to cover 1 m2 of clay surface with
a molecular coverage of 5.2 x 10'1S
cm2/mo!ecule. This assumes that 810
m2/g is the theoretical specific surface
for montmorillonite and that a meas-
ured value of 23.7 mg EGME is re-
tained per gram of clay (Phyal and
Hendricks, 1950).
5.12 Precision and Accuracy
Results should be reported in milligrams
per gram (mg/g) and should be carried out to
four decimal places. A minimum of three
replicates of one sample should be run with
each batch and should yield a %RSD of no
more than 10 percent. All weighings should be
made to ±0.1 mg on an analytical balance.
5.13 References
Blume, L J., M. L Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. U.S.
Environmental Protection Agency, Las
Vegas, Nevada. Appendix A In: Direct/-
DelayedResponse Project Southern Blue
Ridge Province Field Sampling Report:
Vol. I Field Sampling. U.S. Environmental
Protection Agency.
Hillel, D. 1980. Fundamentals of Soil Physics.
Academic Press, New York.
Phyal, R. S., and S. B. Hendricks. 1950. Total
Surface of Clays in Polar Liquids as a
Characteristic Index Soil Sci., Vol. 69,
pp. 421-432.
U.S. Department of Agriculture/Soil Conserva-
tion Service. 1984. Soil Survey Labora-
tory Methods and Procedures for Collect-
ing Soil Samples. Soil Survey Investiga-
tions Report No. 1, USD A. U.S. Govern-
ment Printing Office, Washington, D.C.
-------
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Section 6
Revision 2
Date: 12/86
Page 1 of 4
6 pH Determination
6.1 Scope and Application
The following procedure was developed
to standardize the measurement of pH in soils.
Factors that normally affect the measurement
of pH are (1) electrolyte content of the extract-
ant; (2) soil-to-solution ratio; (3) temperature
and CO2 content of the extract ant; (4) errors
that occur with instrument calibration, stan-
dard preparation, and liquid junction potential;
(5) organic and inorganic constituents; and
(6) length of time the soil and solution stand
before they are measured. These factors were
considered in the preparation of the
methodology.
6.2 Summary of Method
Three suspensions of each soil sample
are prepared, one in DDI water, one in 0.01 M
CaCI2, and one in 0.002 M CaCI2. The pH of
each suspension is measured with a pH meter
and a combination electrode. This method is
modified from USDAySCS (1984).
6.3 Interferences
Soils high in salts, especially sodium
(Na+) salts, may interfere with the pH reading
and the electrode response time.
Clays may clog the KCI junction and may
slow the electrode response time. Thoroughly
clean the electrode between samples to avoid
this problem.
Wiping the electrode dry with cloth,
laboratory tissue, or similiar materials or
removing the electrode from solution when the
meter is not on standby may cause electrode
polarization.
The initial pH of a nonalkaline soil will
usually be as much as 0.5 pH unit greater than
the pH taken after the sample has set for 30
minutes or longer.
The pH will vary as much as 1.0 pH unit
between the supernatant and soil sediment.
Always place the electrode junction at the
same distance above the surface of the soil to
maintain uniformity in pH readings.
6.4 Safety
No specific hazards are associated with
this procedure or with the required reagents.
Normal laboratory safety practices are to be
observed. Protective clothing and safety
glasses should be worn, especially when
handling concentrated HCI and dry Ca(OH)2 to
prepare reagents.
6.5 Apparatus and Equipment
• Digital pH/mV meter, capable of meas-
uring pH to ±0.01 pH unit and poten-
tial to ±1 mV and temperature to ±0.5
°C. The meter must also have auto-
matic temperature compensation
capability.
• pH and reference electrodes, high
quality, low-sodium glass. Geltype
reference electrodes must not be
used. A combination electrode is
strongly recommended, and the proce-
dure is written assuming that one is
used. The Orion Ross combination pH
electrode or equivalent with a retract-
able sleeve junction is recommended.
At least two electrodes, one a backup,
should be available to the analytical
laboratory.
• Beakers, plastic or paper containers,
50 ml_.
• Glass stirring rods or disposable
stirrers, one per sample.
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Section 6
Revision 2
Date: 12/86
Page 2 of 4
3.6 Reagents and Consumable
Materials
• NBS-traceable pH buffers of pH = 4,
pH = 7 and pH - 10, for electrode
calibration.
• Buffer of pH 4.0 for QCCS~The
QCCS can be purchased, or it can be
prepared from 0.05 M potassium hy-
drogen phthalate (KHC8H4O4 or KHP).
This buffer must be from a different
container or lot than the NBS stan-
dards used for electrode calibration.
Dry KHP for 2 hours at 110 °C, cool to
room temperature in a desiccator.
Weigh 10.21 g of KHP, dissolve it in
DDI water, and dilute the solution to
1.000 L To preserve the KHP solution,
add 1.0 mL of chloroform or one
crystal (about 10 mm in diameter) of
thymol per liter of the buffer solution.
This solution has the following pH
values at the temperatures given:
T°C pH
15 3.999
20 4.002
25 4.008
30 4.015
• Double-deionized water (DDI).
• Stock calcium chloride solution (CaCI2,
1.0 M)-Dissolve 55.493 g of anhydrous
CaCI2 in DDI water and dilute to 500
mL
• Calcium chloride 0.01 M CaCI2-Dilute
20 mL of stock 1.0 M CaCI2 to 2.000 L
with DDI water. If the pH of this
solution is not between 5 and 6.5,
adjust the pH by addition of dilute
Ca(OH)2 or HCI, as needed. Verify the
concentration of the CaCI2 solution by
measuring the electrical conductivity.
The specific conductivity should be
2.32 ± 0.08 mmho/cm at 25
prepare fresh solution.
>C. If it is not,
6.7
• Calcium chloride (CaCI2) 0.002 M-
Dilute 4 mL of stock 1.0 M CaCI2 solu-
tion to 2.000 L with DDI water. If the
pH of this solution is not between 5
and 6.5, adjust the pH by addition of
dilute Ca(OH)2 or HCI.
• Calcium hydroxide (CafOHy-Dissolve
0.185 g Ca(OH)2 in 1 L of DDI water.
• Hydrochloric acid (HCI)-Dilute 1 mL
concentrated HCI to 1 L with DDI
water.
Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labo-
ratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the analytical laboratory, all samples are
kept sealed and are refrigerated at 4 °C when
not being used.
6.8 Calibration and
Standardization
For storage and readings, the electrode
need only be immersed to cover the liquid
junction of the reference electrode (typically
about 2.5 cm).
Rinse electrode with DDI water between
each sample and each buffer to prevent solu-
tion carryover. Do not rub or blot electrode
dry because this may produce a static electric
charge and thereby polarize the electrode.
To prepare the pH electrode for use,
move the band covering the fill hole and fill the
reference reservoir to the hole with 4.0 M KCI
filling solution. Allow 5 minutes for the ce-
ramic frit to become wet with filling solution
before immersing the electrode in sample or
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Section 6
Revision 2
Date: 12/86
Page 3 of 4
buffer. The retractable sleeve junction allows
easy cleaning of clay particles and insolubles
that clog the junction and thereby produce drift
and slow response.
Each analyst must be thoroughly ac-
quainted with the procedure and familiar with
all instrument functions. Read and follow all
operating and start-up procedures for the pH
meter. Leave the instrument on standby and
verify that the combination electrode is con-
nected and that the level of reference filling
solution is at least 3 cm above the sample
surface. Check the temperature calibration by
measuring room temperature of a solution with
the electrode and meter and with a thermo-
meter.
Calibrate the electrode at a minimum of
two points that bracket the expected pH and
that are three pH units or more apart. Use
NBS buffers of pH 4, 7, and 10 for samples in
the expected pH range.
Stir pH 4.0 buffer solution for 30 sec-
onds, then stop stirring, read the pH after
equilibration, and adjust the meter if neces-
sary. Perform the step again, using the pH 7.0
buffer. Repeat measurements and adjust-
ments until readings for both buffer solutions
are within 0.1 pH units of the respective true
buffer values. Repeat the process substituting
a pH 10.0 buffer in place of the pH 4.0 buffer
for soils of pH greater than 7.0.
6.9 Quality Control
QC procedures are specified in Section
2.6.
6.9.1 Quality Control Calibration
Sample
Analyze a QCCS, pH 4.0: (1) before
beginning analysis of routine samples, (2) after
every ten samples, and (3) after completion of
routine sample analysis for the day. The value
of the QCCS must be 4.00 ± 0.05. If the
QCCS does not meet this criterion, recalibrate
the electrode according to the procedure in
Section 6.8. Repeat the QCCS measurement
using a fresh QCCS sample. If acceptable
results still cannot be obtained: (1) check
electrode for clean reference junction, (2) check
wiring straps into meter, (3) check for static
electricity from another instrument or from
yourself, and (4) check to see if enough filling
solution is contained within the electrode. If
a problem still persists, replace electrode,
meter, or both.
6.9.2 Blank Samples
Analyze one blank of each suspension
solution. The blank used for each pH method
is the reagent used: DDI water, 0.01 M CaCI2,
or 0.002 M CaCI2.
6.9.3 Replicate Samples
Analyze one sample in triplicate for each
of the following solutions: DDI water, 0.01 M
CaCI2, and 0.002 M CaCI2. Report individual pH
values and the mean and standard deviation
on Form 103a (Appendix C).
6.10 Procedure
1. Prepare two suspensions of each soil
sample, one in DDI water and one in
0.01 M CaCI2, using soil-to-solution
ratios of 1:1 for mineral horizons and
1:5 for organic horizons. For mineral
horizons, add 20 ml_ of the appropri-
ate solution to 20.00 g soil. For or-
ganic horizons, add 25 ml_ solution to
5.00 g soil.
Prepare one suspension of each soil
sample for determination of pH in
0.002 M CaCI2 solution. Use a ratio
of 1:2 for mineral horizons (20 ml
0.002 M CaCI2 to 10 g soil). For most
organic soils, use a ratio of 1:10 (50
mL 0.002 M CaCI2 to 5 g soil); howev-
er, for highly absorbent organic soils,
use a ratio of 1:25 (50 mL 0.002 M
CaCI2 to 2 g soil). The ratio used here
for each sample must correspond with
the ratio used for Lime and Aluminum
Potential (Section 10).
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Section 6
Revision 2
Date: 12/86
Page 4 of 4
2. Allow soil to absorb solution with-
out stirring, then thoroughly stir the
soil-solution mixture for 10 seconds
with a glass stirring rod or disposable
stirrer. Stir again for 10 seconds after
15, 30, 45, and 60 minutes.
3. After the final stirring, allow the
suspension to settle for 1 minute.
Place the pH electrode in the super-
natant of the soil suspension.
For mineral soils, the electrode junc-
tion should be below the solution
surface and above the soil-solution
interface.
Some organic soils swell, so there is
no free water available. As long as
the electrode junction is below the
surface of the organic material, an
acceptable, repeatable reading gener-
ally is attained. If the reading is not
stable, add enough solution to cover
the electrode junction. When the
reading is stable, record pH to the
nearest 0.01 pH unit.
4. Report the pH of the soihDDI water
suspension, the soil:0.01 M CaCI2
suspension, and the soil:0.002 M
CaCI2 suspension for each sample.
5. Analyze three replicates of at least
one sample for each pH solution from
each batch of samples.
6. After measurements are completed,
store the electrode in 0.1 M KCI manu-
factured storage solution. Do not let
the sensing element and reference junction
dry out. The level of the storage solution
should be 1 inch below the filling solution level
to prevent influx of the storage solution.
Check periodically that the electrode reservoir
is full of filling solution.
6.11 Calculations
No calculations are required to obtain pH
values. The mean and standard deviation
must be determined for the triplicate samples
for each pH solution.
6.12 Precision and Accuracy
The standard deviation of the blanks is
a measure of the precision of the method.
6.13 References
Blume, L J., M. L Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. U.S.
Environmental Protection Agency, Las
Vegas, Nevada. Appendix A In: Direct/-
DelayedResponse Project Southern Blue
Ridge Province Field Sampling Report:
Vol. I Field Sampling. U.S. Environmental
Protection Agency.
U.S. Department of Agriculture/Soil Conserva-
tion Service. 1984. Soil Survey Laborato-
ry Methods and Procedures for Collecting
Soil Samples. Soil Survey Investigations
Report No. 1, USDA. U.S. Government
Printing Office, Washington, D.C.
-------
7 Cation Exchange Capacity
Section 7
Revision 2
Date: 12/86
Page 1 of 10
7.1 Scope and Application
Cation exchange capacity (CEC) is a
measure of the negative charge that exists on
organic and mineral colloids allowing the
particle surfaces to exchangeably bind cations.
The quantity of cations needed to neutralize
the charge is measured in milliequivalents per
100 g of oven-dried soil. A close approxima-
tion of CEC is the summation of exchangeable
acidity and exchangeable bases. CEC con-
sists of permanent charge CEC and pH-
dependent CEC. Permanent charge CEC is a
result of isomorphic substitution of the
central cation within the clay structure. The
pH-dependent CEC, a result of interrupted
lattice structure at the clay particle surface
and of the dissociation of functional groups,
varies with H+ ion concentrations. Two satu-
rating solutions are used for CEC determina-
tion. Ammonium acetate (1.0 N NH4OAc)
buffered at pH 7 yields a theoretical estimate
of the maximum CEC potential for a specific
soil. For this reason, it is termed total CEC.
In acid soils, this estimate results in a high
CEC value because of adsorption of NH4+ ions
to the pH-dependent exchange sites that exist
at a neutral pH level. This overestimation will
not occur when a neutral unbuffered saturating
solution (1.0 N NH4CI) is used. For this study,
ammonium chloride (1.0 N NH4CI) and ammo-
nium acetate (1.0 N NH4OAc) will be used.
This NH4CI CEC has been termed effective
CEC or that which occurs at field pH. This
parameter will be of greater importance be-
cause it is a more realistic estimate of CEC
than is the the total CEC (NH4OAc).
Micaceous clay minerals such as biotite,
vermiculite, and muscovite contain K+ and NH4+
as interlayer cations. These cations are not
readily exchangeable, and soils containing
large quantities of these silicate minerals will
produce erroneous results when NH4+ is used
to replace cations. These minerals generally
occur only in soils found in the Western United
States.
7.2 Summary of Method
The soil sample is saturated with NH4+
from a solution of NH4OAc; excess NH4+ is
removed by ethanol rinses. The sample is
then analyzed for NH4+ content by one of three
methods: automated distillation-titration;
manual distillation-automated titration; or
ammonium displacement - flow injection analy-
sis. The entire procedure is repeated with a
fresh aliquot of sample and a solution of
NH4CI as the NH4+ source. This method is
based on Doxsee (1985), Rhodes (1982), and
USDA/SCS (1984).
7.3 Interferences
Inconsistency in the NH4* saturating and
rinsing steps is the greatest source of error.
Soils containing minerals such as biotite,
vermiculite, and muscovite (which contain K+
or NH4+) will produce artificially low results.
The use of a mechanical extractor minimizes
inconsistency.
7.4 Safety
Wear protective clothing (laboratory coat
and gloves) and safety glasses when prepar-
ing reagents, especially when concentrated
acids and bases are used. The use of concen-
trated acids and hydroxide solutions should be
restricted to a hood.
7.5 Apparatus and Equipment
Apparatus and equipment required are
for the saturation procedure and for the analy-
tical procedure that is selected for use. It is
not necessary to have equipment for all three
analytical procedures.
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Section 7
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Page 2 of 10
7.5.1 Apparatus for Saturation
Procedure
• Mechanical extractor, 24 place (see
Figure 7-1).
• Syringes, disposable, 60 mL poly-
propylene (Use one sample tube, one
reservoir tube, and one tared extrac-
tion syringe for each sample).
• Rubber tubing, 1/8 x 1/4 inch (for con-
necting syringe barrels).
• Analytical filter pulp, Schleicher and
Schuell, No. 289, washed according to
the procedure given in Section 2.4.
• Bottles, polyethylene (LPE), 25 mL.
• Reciprocating shaker.
\
• Tubes, glass, centrifuge or culture,
with caps, 25 mL
7.5.2 Apparatus for Automated
Distillation- Titration
Analysis
• Steam distillation-titration apparatus,
Kjeltec auto 1030 analyzer, or compa-
rable unit.
• Printer, Alphacom 40, or equivalent.
• Digestion tubes, 250 ml, straight
neck.
7.5.3 Apparatus for Manual
Dis tilla tion-Automa ted
Titration Analysis
• Automatic titrator with autosampler,
Metrohm or equivalent.
• Kjeldahl flasks, 800 mL
7.5.4 Apparatus for Ammonium
Displacement-Flow Injection
Analysis
• Flow injection analyzer (FIA), Lachat
or equivalent, modified for ammonia
chemistry with 630 nm interference
filter.
7.6 Reagents and Consumable
Materials
Reagents and consumable materials
required are for the saturation procedure and
for the analytical procedure that is selected
for use. It is not necessary to have the re-
agents for all three analytical procedures.
7.6. 1 Reagents for Saturation
Procedure
• Glacial acetic acid
• Ammonium hydroxide (NH4OH), con-
centrated.
• Ammonium acetate (NH4C2H3O2 or
NH4OAc), 1 N, pH 7.0~Purchased or
made according to one of the follow-
ing procedures:
1. To 15 L DDI water in a 20-L bottle,
add 1,026 ml glacial acetic acid,
mix, then add 1,224 mL concen-
trated ammonium hydroxide. Mix,
cool, dilute to 18 L with DDI water,
and adjust pH to 7.0 with acetic
acid or with ammonium hydroxide.
2. To 15 L DDI water in a 20 L bottle,
add 1,388 g crystalline ammonium
acetate (reagent grade). Mix, allow
to come to ambient temperature,
then dilute to 18 L with DDI water.
Adjust to pH 7.0 with acetic acid or
with ammonium hydroxide.
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Section 7
Revision 2
Date: 12/86
Page 3 of 10
Figure 7-1. Mechanical extractor. Thla extractor la a mechanical device that can be uaed to perform an extraction
by leaching technique. (Manufactured by Centurion International, Inc., P.O. Box 82846, 4555 North
48th Street, Uncoln, Nebraaka 68501.).
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Section 7
Revision 2
Date: 12/86
Page 4 of 10
Ammonium chloride (NH4CI), spectro-
scopic grade, 1 N-Dissolve 535 g
NH4CI in DDI water and dilute to 10
L. Two sources of spectroscopic
grade NH4CI are (1) Aldrich Chemical
Company, Inc., 940 West Saint Paul
Avenue, Milwaukee, Wisconsin 53233;
telephone (800) 558-9160, No. 25,413-
4, and (2) Aesar - Johnson Matthey,
Inc., Eagles Landing, P.O. Box 1087,
Seabrook, New Hampshire 03874;
telephone (800) 343-1990, No. 10632.
• Ethanol
U.S.P.
(CH3CH2OH), 95 percent,
• Nessler's reagent.
1. Add 4.56 g potassium iodide (KI) to
30 mL DDI water in a beaker. Then
add 5.68 g mercuric iodide (HgI2).
Stir until dissolved.
2. Dissolve 10 g NaOH in 200 mL DDI
water.
3. Transfer NaOH solution to 250-mL
volumetric flask. Add Hg solution
slowly, then dilute to volume and
mix thoroughly. Solution should not
contain a precipitate. It can be
used immediately.
7.6.2 Reagents and Consumable
Materials for Automated
Distillation-Titration
Analysis
• Sodium chloride (NaCI).
• Antifoam, silicone spray bottle.
• Hydrochloric acid (HCI), 0.10 N, stan-
dardized-Purchased or prepared by
the following procedure: Add 150 mL
concentrated HCI to approximately 15
L DDI water, dilute to 18 L Standard-
ize against sodium carbonate.
Standardize 0.1 N HCI with the follow-
ing equipment and method:
1. Apparatus
(a) Automatic titrator (buret,
optional).
(b) Erlenmeyer flasks, 250 mL.
2. Reagents
(a) Hydrochloric acid (HCI) , 0. 1 N.
(b) Sodium carbonate (NajCOJ,
primary standard grade.
(c) Methyl orange indicator solu-
tion, 0.1 percent aqueous
solution.
3. Procedure
Dry Na2CO3 for 2 hours at 110 °C.
Cool in a desiccator. Weigh 0.25 g
± 0.1 mg Na2CO3 into 250-mL Erlen-
meyer flasks. Dissolve in about 50
mL DDI water. Add 3 drops methyl
orange indicator and titrate with
HCI until the first permanent pink
end-point (pH = 4.0).
• Boric acid (H^Og), 4 percent (w/v)
aqueous solution-Add 720 g boric
acid to about 4 L DDI water in a
large stainless steel beaker. Heat
to near boiling and stir until crys-
tals dissolve. Fill a 5-gallon Pyrex
solution bottle with about 12 L DDI
water. Transfer hot solution
through a large polyethylene funnel
into the bottle. Dilute to 18 L with
DDI water and mix well.
7.6.3 Reagents and Consumable
Materials for Manual
Distillation-Automatic
Titration Analysis
• Sodium chloride (NaCI).
• Antifoam mixture-Mix equal parts of
mineral oil and octanol.
Boric acid (H
Section 7.6.2).
, 4 percent-(See
Hydrochloric acid (HCI), 0.10 N,
standardized-Purchased or prepared
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Section 7
Revision 2
Date: 12/86
Page 5 of 10
by the following procedure: Add
150 mL concentrated HCI to approxi-
mately 15 L DDI water. Dilute to 18
L. Standardize against sodium car-
bonate as described in Section 7.6.2.
• Sodium hydroxide (NaOH), 1 N-Add
500 mL 50 percent NaOH solution to
8 L of DDI water in a 9.5-L Pyrex
solution bottle. Dilute to 9 L with DDI
water and mix well.
• Zinc, granular.
7.6.4 Reagents and Consumable
Materials for Ammonium
Displacement-Flow Injection
Analysis
The reagents and consumable materials
used depend on recommendations of the man-
ufacturer of the FIA and may vary by make
and model.
• Hydrochloric acid 0.1
Section 7.6.2).
N (HCI)--(see
• Nitroferricyanide reagent-Dissolve
40 g potassium sodium tartrate
(KNaC4H4Oe) and 30 g sodium citrate
(Na3C8H5O7-2H2O) in 500 mL DDI
water. Add 10 g sodium hydroxide
pellets (NaOH). Add 1.5 g sodium
nitroferricyanide (Na2Fe(CN)5-
NO*2H2O), dilute to 1.00 L, and mix
well. Store in a dark bottle. Prepare
fresh solution monthly.
• Sodium hypochlorite reagent-Dissolve
20 g sodium hydroxide and 20 g boric
acid in 150 mL of DDI water. Add 800
mL 5 percent solution NaOCI (house-
hold bleach). Dilute to 1.00 L with
DDI water. Store in a dark bottle.
Prepare fresh solution monthly.
• Sodium phenate reagent-Dissolve 95
mL 88 percent liquified phenol in 600
mL DDI water. While stirring, slowly
add 120 g NaOH. Cool. Add 100 mL
7.7
ethanol and dilute to 1.00 L Store in
a dark bottle.
• Nitrogen standard solution, 1,000 mg
N/L-Dissolve 3.819 g ammonium chlo-
ride (NH4CI), dried at 105 °C, in DDI
water and dilute to 1.00 L. Pipet 15.0,
10.0, 6.0, and 2.0 mL of this solution
into 100-mL volumetric flasks. Take
to volume with 0.1 N HCI. This will
yield 150, 100, 60, and 20 mg N/L
working standards. Pipet 5 mL of the
100 mg N/L working standard into a
100-mL volumetric flask and dilute to
volume with 0.1 N HCI. This provides
a 5 mg N/L working standard. Prepare
fresh working standards weekly.
Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labor-
atory and are refrigerated at 4 °C. If this time
requirement cannot be met, the samples are
placed in a cooler after they are collected. In
the analytical laboratory, all samples are kept
sealed and are refrigerated at 4 °C when not
being used.
7.8 Calibration and
Standardization
Use standards containing 0, 5, 20, 60,
100, and 150 mg N/L as NH« to develop a cali-
bration curve. A regression of the standard
curve should have an intercept close to zero.
A QCCS is run immediately after the calibra-
tion standards and is run again after every
tenth sample. Air bubbles produce sharp
sudden peaks which destroy the calibration
curve. In the event of air bubbles, the calibra-
tion curve and all samples between QCCSs
(as many as 10 samples) must be reanalyzed.
Standard values should not vary by more than
5 %RSD. Standardization is accomplished
through use of the mechanical extractor, volu-
metric glassware, and repipets (automatic
pipettors).
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Section 7
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Page 6 of 10
7.9 Quality Control
QC procedures are specified in Section
2.6. One sample is run in duplicate for each
saturating solution with each batch of sam-
ples. Three reagent blanks are processed for
each saturating solution with each batch of
samples, and the mean and standard deviation
of the results for each are recorded.
If CEC is determined by FIA, the QCCS
is a solution; QCCSs are run immediately after
the calibration curve is established and after
every tenth sample. There is no QCCS for the
distillation-titration method; however, the acid
used for titration must be restandardized
weekly.
Matrix spikes are required for both meth-
ods. Use a solution of NH4CI or (NHJj,SO4 as
the spiking solution. For FIA, the final dis-
placed solution (Section 7.10.4.1, step 1) may
be split, and the matrix spike may be added to
one split. For distillation-titration, a second
sample must be processed, and the matrix
spike must be added to the sample just prior
to distillation.
7.10 Procedure
The following procedure is performed
twice for each sample; once with an NH4OAc
solution as the NH4 source for the saturating
procedure, and once with an NH4CI solution
as the NH4+ source. The NH4 adsorbed by the
soil is measured by one of the three analytical
procedures given in sections 7.10.2, 7.10.3, and
7.10.4.
7.10.1 Saturation Procedure
1. Prepare sample tubes by tightly com-
pressing a 1-g ball of filter pulp into
bottom of syringe barrel with a modi-
fied plunger. Modify the plunger by
removing the rubber portion of the
plunger, and cut off the plastic
protrusion.
2. For mineral soils, weigh 2.50 ± 0.01 g
air-dried soil and place in sample
tube. Place sample tube in upper disc
of extractor and connect to inverted
tared extraction syringe, the plunger
of which is inserted in the slot of the
stationary disc of the extractor. Fill
syringe to 20-mL mark with NH4OAc.
Stir sample and NH4OAc with glass
stirring rod for 15 seconds, rinse rod
with NH4OAc, and fill syringe to 25-ml
mark. Let stand for 20 minutes. Con-
tinue at step 3.
For organic soils, weigh 2.50 ± 0.01 g
of air-dried soil into a small glass
tube. Add 2 mL of ethanol as a wet-
ting agent. (If the organic soil wets
easily, it is not necessary to add the
ethanol.) When the soil is moistened,
add 15 mL NH4OAc, cap, and shake
for 1 hour on a reciprocating shaker.
Place sample tube in upper disc of ex-
tractor and connect to inverted, tared
extraction syringe, the plunger of
which is inserted in the slot of the
stationary disc of the extractor. Then
quantitatively transfer the sample and
NH4OAc to the sample tube and fill to
the 30-mL mark with NH4OAc. Let
stand for 20 minutes. Continue at
step 3.
3. Put reservoir tube on top of sample
tube. Extract rapidly until NH4OAc is
at a depth of 0.5 to 1.0 cm above
sample. Turn off extractor. Add
about 45 mL NH4OAc to reservoir
tube, turn on extractor, and extract
overnight or for approximately 17
hours.
4. The next morning, switch off extractor
and pull plungers down as far as
extractor will allow. Disconnect sy-
ringes from sample tubes, leaving
rubber connectors on sample tubes.
Weigh each syringe containing the
NH4OAc extract to the nearest 0.01 g.
Use the following density factor of
the solutions to convert solution
weight to volume: 1.0124 g/cm3 for
NH4OAc, 1.0106 g/cm3 for NH4CI.
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Section 7
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Date: 12/86
Page 7 of 10
(As an alternative, quantitatively trans-
fer the solution recovered in the sy-
ringe to a volumetric flask and dilute
to volume. This solution is reserved
for analysis of exchangeable basic
cations as described in Section 8.)
5. Mix the extract in each syringe by
shaking manually. Rinse the poly-
ethylene bottle twice with small vol-
umes of the extract solution, then fill
the container with extract solution,
and discard the excess. This solution
is reserved for analysis of exchange-
able cations as described in Section 8.
6. Return upper 2-disc unit to starting
position. Attach the syringes to the
sample tubes, and rinse the sides of
sample tubes with ethanol from a
wash bottle. Fill sample tubes to the
20-mL mark, stir, and let stand for 15
to 20 minutes. Place reservoir tube
in sample tube. Extract rapidly until
the level of ethanol is 0.5 to 1.0 cm
above sample. Turn off extractor and
add enough ethanol to the reservoir to
ensure an excess over the capacity of
the syringe. Extract for 45 minutes.
7. After the extractor has stopped, turn
off the switch, pull the plungers
down, remove syringes, and discard
the ethanol wash. Return the upper
unit of the extractor to starting posi-
tion, reattach syringes to the sample
tube, fill reservoir tubes with about 45
mL ethanol, and extract a second time
for approximately 45 minutes.
When extractor has stopped, remove
syringes and discard ethanol. After
the second ethanol extraction, collect
a few drops of ethanol extract on a
spot plate. Test for residual NH4+ in
each sample by using Nessler's re-
agent. If the test is positive, repeat
another ethanol extraction of the af-
fected samples and test by using Ne-
ssler's reagent until a negative test is
obtained. If analyzing by FIA, go to
Section 7.10.4.
8. Remove sample tubes and quantita-
tively transfer each sample to a 800-
mL Kjeldahl flask, if direct distillation
is used, or to a 250-mL digestion tube,
if steam distillation is used. To
remove the sample, blow the filter
pulp and soil out of the syringe by
using a gentle flow of compressed
air. Wash with a minimum of CO2-
free, DDI water. Use a rubber police-
man to complete the transfer. The
solution is reserved for analysis as
described in sections 7.10.2, 7.10.3, or
7.10.4.
7.10.2 Analytical Procedure using
Automated Distillation-
Tit rat ion
To soil and filter pulp in a 250-mL diges-
tion tube (from Section 7.10.1, step 7), add 6
to 7 g sodium chloride. Refer to the instruc-
tional manual for operation of the Kjeltec auto
1030 analyzer or other similar unit. Spray
silicone antifoam solution into the digestion
tube and connect it to the distillation unit.
Close the safety door. The distillation, titra-
tion, and calculation are performed automati-
cally in about 4 minutes. The result is printed
in milliliters of titrant.
7.10.3 Analytical Procedure using
Manual Distillation-
Automated Titration
To soil and filter pulp in 800-mL Kjeldahl
flask (from Section 7.10.1, step 7), add 400 mL
DDI water and 10 g NaCI, 5 drops antifoam
mixture, 1 to 2 g granular zinc, and 40 mL 1 N
NaOH. Connect the flask with the condenser
of the Kjeldahl unit. Turn on cooling water of
condenser and heat sample, being careful not
to allow sample to boil over into condenser.
If excessive foaming occurs or solution ap-
pears about to boil over, reduce the heat
source. Should the sample boil over into the
trap or beyond the trap into the condenser, the
system should be thoroughly steamed and
back-flushed before using again.
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Page 8 of 10
Collect 175 to 180 ml_ distillate in a 250-
mL plastic titrator beaker containing 50 ml.
4 percent boric acid solution. Transfer beakers
to titrator magazines and load onto sample
changer of automatic titrator. Titrate with
0.10 N HCI to a pH 4.60 end point. Follow
instructions for operation of Metrohm automat-
ic titrator or other comparable instrument in
setting up instrument for titration for cation
exchange capacity.
7.10.4 Analytical Procedure using
Ammonium Displacement-
Flow Injection Analysis
• This procedure is modified from Dox-
see (1985). Continue from Section
7.10.1, step 7, after the second extrac-
tion of 45 ml ethanol. Add 50 mL 0.1
M HCI and extract at a setting of 10
(approximately 1 hour) until all the
leachate has passed through the soil.
Switch off extractor and pull plungers
down as far as extractor will allow.
Disconnect syringes from sample tube
and leave the rubber connector on the
sample tube. Save filtrate for analysis
on the flow injection analyzer.
• The following procedure is specific for
a Lachat FIA. If another FIA is used,
the laboratory must follow the operat-
ing procedures for that instrument.
1. Turn on the instrument and related
peripheral equipment.
2. Adjust the instrument and peripher-
als according to the manufacturer's
specifications necessary for the
method.
3. Check all connections on chemistry
manifolds to be sure none are
loose. Also check pump lines for
wear. Remove dilution line from
ammonia manifold and put CEC
sample loop in place on valve.
4. With pump on regular speed, apply
tension on pump tube and immerse
pump lines into appropriate
Table 7-1. Typical Purpose and Size of Each Pump
Tub*
Tubing Size
Pump Line (Color Code)
Distilled water for sampler Green/green
Cyanide reagent Orange/orange
Phenate reagent Orange/orange
Hypochlorite reagent White/white
Distilled water for ammonium reaction Blue/blue
Degas line for ammonia reaction Orange/white
Valve pump Green/green
reagent bottles (see Table 7-1).
Color and purpose of each tube
will vary with the instrument and
method used.
5. Insert the pens into the chart
recorder. After the baselines have
stabilized, use the zero potentiom-
eter on the colorimeter to zero each
of the channels. The reading on
the colorimeter should be within the
manufacturer's specified range for
each channel.
6. Activate the computer which is
used to operate the FIA system.
7. Prepare standards containing 150-
100-, 50-, 20-, and 0-mg N/L as
NH/ for use in developing a cali-
bration curve and for standard
checks every tenth sample.
8. Adjust peak height on a chart
recorder to full scale for the 150-
mg N/L as NH4+ standard.
9. Analyze the solutions, blanks, and
standards following the manufac-
turer's procedure.
10. After the samples have been ana-
lyzed, follow the manufacturer's in-
structions for cleaning and shutting
down the instrument.
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Section 7
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Page 9 of 10
7.10.5 NH4CI Saturation
Procedure
After completion of analysis by the
steps given in Sections 7.10.2, 7.10.3, or 7.10.4,
repeat the entire process with fresh samples
(starting with Section 7.10.1), except use NH4CI
instead of NH4OAc throughout the saturation
procedure.
7.11 Calculations
All CEC results are reported to the near-
est 0.01 meq/100g oven-dry equivalent-weight
soil.
7.11.1 Results from Either
Dis til la tion- Titra tion
Analytical Procedure
(Section 7.10.2 or 7.10.3)
Results are provided by the analysis
or titration unit in milliliters of titrant ( 0.1 N
HCI). To determine CEC, use the following
equation:
(mL HCI)
CEC (meq/100 g)
Normality of acid
oven-dry sample wt (g)
where
Oven-dry sample wt (g)
100 - % moisture
(100)
(7-1)
100
air-dry sample wt (g)
(7-2)
7.11.2 Results from Ammonium
Displacement-Flow Injection
Analysis Procedure (Section
7.10.4.)
Results are provided by computer as
milligrams nitrogen per liter or milliequivalents
NH4* per liter depending upon how the stan-
dards are set up. To determine CEC, one of
the following equations is used:
7.11.2.1 Using mg N/L
CEC (meq/100 g)
L
mg N
1000 mL
50 mL extract
oven-dry soil 14.0067 ma N
sample wt (g) meq
(100 g Soil)
(7-3)
7.11.2.2 Using meq NH//L-
CEC (meq/100 g) =
50 mL extract
(100 g Soil)
meq NH4+ 1000 mL
L
Oven-dry soil
sample wt (g)
where: Oven-dry soil sample wt (g)
100 - % moisture air-dry soil
sample wt (g)
(7-4)
100
and meq NH + = 18.0383 mg
7.12 Precision and Accuracy
Relative intralaboratory precision is within
10 percent. For most soils, the NH4OAc CEC
should be greater than the NH4CI CEC.
7.13 References
Blume, L. J., M. A. Papp, K. A Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil
Sampling Manual lor the Direct/Delayed
Response Project Soil Survey. U.S.
Environmental Protection Agency, Las
Vegas, Nevada. Appendix A In: Direct/-
Delayed Response Project Southern Blue
Ridge Province Field Sampling Report:
Vol. I Field Sampling. U.S. Environmental
Protection Agency, Las Vegas, Nevada.
Doxsee, Kari. 1985. Cation Exchange Capacity
in Nursery Soils Using FIA (Flow Injec-
tion Analysis). Am. No. 1503-15. Weyer-
haeuser Technology Center, Research
Division, Tacoma, Washington.
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Page 10 of 10
Rhodes, J. D. 1982. Cation Exchange Capaci-
ty, pp. 149-158. In: Methods of Soil
Analysis: Part 2- Chemical and Microbi-
ological Properties, Second Edition, A. L
Page, R. H. Miller, and 0. R. Keeney
(eds.). American Society of Agronomy,
Inc./Soil Science Society of America, Inc.,
Madison, Wisconsin.
United States Department of Agriculture/Soil
Conservation Service. 1984. Soil Survey
Laboratory Methods and Procedures for
Collecting Soil Samples. Soil Survey
Investigations Report No. 1, USDA. U.S.
Government Printing Office, Washington,
D.C.
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8 Exchangeable Basic Cations
8.1 Scope and Application
The exchangeable cations (Ca2+, Mg24,
K+, and Na+) in the soil can be used to esti-
mate the fertility of a soil and its ability to
buffer against acidic deposition. Ammonium
chloride and buffered ammonium acetate are
used to estimate exchangeable basic cations
at the soil pH and at the buffered pH.
Base saturation is given as the total
amount of exchangeable basic cations divided
by the CEC. Cation exchange sites not occu-
pied by basic cations are assumed to be
occupied by acidic cations such as hydrogen
and aluminum.
Cation exchange capacity relates to the
buffering capacity of the soil. Base saturation
is a measure of how much buffering capacity
remains in the soil. Exchangeable acidity is a
measure of the amount of exchangeable basic
cations which have been displaced by acidic
cations (H+, AI3+) through weathering and acid
deposition.
Inductively coupled plasma emission
spectroscopy (ICP) may be used to analyze
the extracts for sodium, calcium, and magne-
sium. Flame atomic emission spectroscopy
(flame photometry) may be used for potassium
and sodium determinations. The AA and ICP
methods described here are taken from Meth-
ods for Chemical Analysis of Water and
Wastes (U.S. EPA, 1983). The flame photomet-
ric method is taken from Standard Methods
for the Examination of Water and Wastewater
(APHA et al., 1985).
The following concentration ranges of
analytes may be expected in the soil extracts
(Table 8-1).
Typical performance data for concentra-
tion range, sensitivity, and detection limit may
be obtained from Table 8-2.
Tabl* 8-1. Expsctsd Rang* of Analyts
Concentrations In Soil Extracts
Analyte
meq/L
mg/L
Ca"
Mg"
K*
Na*
0-30
0-10
0-05
0-20
0-600
0-122
0-196
0-460
Recommended wavelengths and esti-
mated detection limits for ICP analysis are
given in Table 8-3.
When analyzing by flame photometry, the
better instruments can be used to determine
sodium levels approximating 100 jug/L With
proper modifications in technique, the range of
sodium measurement can be extended to 10
fjg/L or lower. Potassium levels of approxi-
mately 0.1 mg/L can be determined.
8.2 Summary of Method
Previously prepared extracts from the
CEC procedure (Section 7) are analyzed for
calcium, magnesium, potassium, and sodium
by one or by a combination of the following
methods.
Once the concentration of each cation in
the soij extract is determined, the cation con-
centrations in the original soil sample may be
calculated.
8.2. 1 Atomic Absorption (for
/T, and Na+)
A portion of the extract is aspirated into
the AA unit and is atomized in a flame. A light
beam from a hollow cathode lamp, whose
cathode is made of the element to be deter-
mined, is directed through the flame into
a monochromator and onto a detector that
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Table 8-2. Atomic Absorption Performance Data for Determination of C«2+, Mg2+, K+, and Na4 (U.S. EPA, 1983)
Ca2+
-.2+
Optimum concentration
range 0.2-7 mg/L
Wavelength 422.7 nm
Sensitivity 0.08 mg/L
Detection limit 0.001 mg/L
0.02-0.05 mg/L
285.2 nm
0.007 mg/L
0.001 mg/L
0.1-2 mg/L
768.5 nm
0.04 mg/L
0.01 mg/L
0.3-1 mg/L
589.6 nm
0.15 mg/L
0.002 mg/L
Table 8-3. Recommended Wavelengths and Estimated
Instrumental Detection Limits for
Inductively Coupled Plasma Analysis
Element Wavelength8 (nm)
Estimated detection
limit (/J/L)b
Calcium
Magnesium
Sodium
317.933
279.079
588.995
10
30
29
The wavelengths are listed because of their
sensitivity and overall acceptance. Other wave-
lengths may be substituted if they can provide
the needed sensitivity and if they are treated with
the same corrective techniques for spectral
interference.
The estimated instrumental detection limits as
shown are taken from Fassel, 1982. They are
given as a guide for an instrumental limit. The
actual method detection limits are sample-depen-
dent and may vary as the sample matrix varies.
measures the amount of light absorbed.
Absorption depends upon the presence of free
unexcited ground state atoms in the flame.
Since the wavelength of the light beam is
characteristic of only the metal being deter-
mined, the light energy absorbed by the flame
is a measure of the concentration of that
metal cation in the extract.
8.2.2 Inductively Coupled Plasma
(for Caz\ Mgz+, and Na+)
The method is based on the measure-
ment of atomic emission by optical spectros-
copy. Samples are nebulized to produce an
aerosol. The aerosol is transported by an
argon carrier stream to an inductively coupled
argon plasma (ICP), which is produced by a
radio frequency (RF) generator. In the plasma
(which is at a temperature of 6,000 to 10,000
°K) the analytes in the aerosol are atomized,
ionized, and excited. The excited ions and
atoms emit light at their characteristic wave-
lengths. The spectra from all analytes are
dispersed by a grating spectrometer, and the
intensities of the lines are monitored by photo-
multiplier tubes. The photocurrents from the
photomultiplier tubes are processed by a
computer system. The signal is proportional
to the analyte concentration and is calibrated
by analyzing a series of standards (U.S. EPA
1983; Fassel, 1982).
A background correction technique is
required to compensate for variable back-
ground contribution to the determination of
trace elements. Background must be meas-
ured adjacent to analyte lines during sample
analysis. The position selected for the back-
ground intensity measurement, on either side
or both sides of the analytical line, will be
determined by the complexity of the spectrum
adjacent to the analyte line. The position used
must be free of spectral interference and
must reflect the same change in background
intensity as occurs at the analyte wavelength
measured. Generally, each instrument has
different background handling capabilities. The
instrument operating manual should be con-
sulted for guidance.
8.2.3 Flame Photometry (for K+
and Na*)
Trace amounts of sodium and potassium
are determined by flame emission photometry
at wavelengths of 589 and 766.5 nm, respec-
tively. The sample is sprayed into a gas
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flame, and excitation is carried out under
carefully controlled and reproducible condi-
tions. The desired spectral line is isolated by
the use of interference filters or by a suitable
slit arrangement in light-dispersing devices
such as prisms or gratings. The intensity of
light is measured by a phototube potentio-
meter or other appropriate circuit. The intensi-
ty of light at the appropriate wavelength, e.g.,
589 nm for Na+, is approximately proportional
to the concentration of the element. If align-
ment of the wavelength dial with the prism is
not precise in the available photometer, the
exact wavelength setting can be determined
from the maximum needle deflection and then
can be used for the emission measurements.
The calibration curve may be linear but has a
tendency to level off at higher concentrations.
8.3 Interferences
Three types of interferences, spectral,
chemical, and physical, can be identified for
the analytical portion of the method. These
vary in importance depending on the particular
analytical procedure chosen.
8.3.1 Spectral Interferences
Spectral interferences can be categorized
as (1) overlap of a spectral line from another
element, (2) unresolved overlap of molecular
band spectra, (3) background contribution from
continuous or recombination phenomena, and
(4) background contribution from stray light
from the line emission of high-concentration
elements. The first of these effects can be
compensated for by utilizing a computer cor-
rection of the raw data. This correction re-
quires monitoring and measurement of the
interfering element. The second effect may
require selection of an alternate wavelength.
The third and fourth effects can usually be
compensated by a background correction
adjacent to the analyte line. In addition, users
of simultaneous multielement instrumentation
must assume the responsibility of verifying the
absence of spectral interference from an
element that could occur in a sample but for
which there is no channel in the instrument
array.
Spectral interference in AA determina-
tions is rare but can occur when an absorbing
wavelength of an element present in the sam-
ple, but which is not being determined, falls
within the width of the absorption line of the
analyte. The results of the determination will
then be erroneously high because of the contri-
bution of the interfering element to the atomic
absorption signal. Also, interference can occur
when resonant energy from another element in
a multielement lamp or a metal impurity in the
lamp cathode falls within the bandpass of the
slit setting and when that metal is present in
the sample. This type of interference may
sometimes be reduced by narrowing the slit
width.
8.3.2 Chemical Interferences
Chemical interferences are characterized
by molecular compound formation, ionization
effects, and solute vaporization effects. For all
determinations, chemical interference is the
most troublesome type of interference and is
caused by lack of absorption of atoms bound
in molecular combination in the flame. This
phenomenon can occur when the flame is not
sufficiently hot to dissociate the molecule, as
in the case of phosphate interference with
magnesium, or because the dissociated atom
is immediately oxidized to a compound that
will not dissociate further at the temperature
of the flame. The addition of lanthanum will
overcome the phosphate interference in the
magnesium and calcium determinations.
Chemical interferences may also be eliminated
by separating the cation from the interfering
materials. While they are primarily employed
to increase the sensitivity of the analysis,
complexing agents may also be used to elimi-
nate or reduce interferences.
Ionization interferences occur when the
flame temperature is sufficiently high to re-
move an electron from a neutral atom, thereby
giving a positively charged ion. This type of
interference generally can be controlled by
the addition, to both standard and sample
solutions, of a large excess of an easily ion-
ized element.
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Normally, chemical interference is negli-
gible with the ICP technique. If observed,
chemical interference can be minimized by
careful selection of operating conditions, e.g.,
incident power or observation position, by
buffering the sample, by matrix matching, and
by standard addition procedures. Chemical
interference can be highly dependent on the
matrix type and the specific analyte.
Flame photometers operating on the
internal standard principle may require adding
a standard lithium solution to each working
standard and sample in order to control chemi-
cal interference. The optimum lithium concen-
tration may vary among individual instruments.
To suppress ionization and anion interfer-
ence, radiation buffers should be added to
sample and standard solutions. Among com-
mon anions capable of causing radiation
interference are CI", SO*2", and HCO3" in relative-
ly large amounts.
In the same manner as for AA analysis,
chemical interference may be removed by
separating the cation from the interfering
material. When using the internal standard
method for sodium determinations, potassium
and calcium may interfere if the potassium-to-
sodium ratio is greater than or equal to 5:1
and when the calcium-to-sodium ratio is great-
er than or equal to 10:1. When these ratios
are exceeded, measure calcium and potassium
first so that the approximate concentration of
interfering ions may be added to the sodium
calibration standards. Magnesium interfer-
ence does not appear until the magnesium-to-
sodium ratio exceeds 100:1, a rare occurrence.
For potassium determinations by the
internal standard method, interference may
occur at sodium-to-potassium ratios of 5:1 or
greater. Calcium may interfere if the calcium-
to-potassium ratio is 10:1 or more. Magnesium
begins to interfere when the magnesium-to-
potassium ratio exceeds 100:1.
8.3.3 Physical Interferences
For ICP determinations, physical interfer-
ences are generally considered to be associ-
ated with the sample nebulization and trans-
port processes. Changes in viscosity and
surface tension can cause significant inaccura-
cies, especially in samples that contain high
amounts of dissolved solids or high acid
concentrations. The use of a peristaltic pump
may lessen these interferences. If they are
occurring, these types of interferences must be
reduced by either dilution of the sample or by
utilization of standard addition techniques.
High dissolved solids may also cause salt
buildup at the tip of the nebulizer. This affects
aerosol flow rate and causes instrumental
drift. Wetting the argon prior to nebulization,
the use of a tip washer, and sample dilution
have been used to control this problem. It
has been reported that better control of the
argon flow rate improves instrument perform-
ance. This is accomplished with the use of
mass flow controllers.
For flame photometric determinations,
burner-clogging particulate matter may be
removed from the sample solution by filtering
the solution through a quantitative filter paper
of medium retentiveness. A nonionic detergent
may be incorporated in the standard lithium
solution to ensure proper aspirator function.
8.3.4 Matrix Effects
Whenever a new or unusual sample
matrix is encountered, a series of tests should
be performed prior to reporting concentration
data for the analyte. Such tests ensure that
neither positive nor negative interferences are
affecting any of the analytes, thereby distort-
ing the accuracy of the reported values. These
tests are the following:
8.3.4.1 Serial Dilution-
If the analyte concentration is sufficient-
ly high (minimally a factor of 10 above the
instrumental detection limit after dilution), an
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analysis of a dilution should agree within 5
percent of the original determination (or within
some acceptable control limit that has been
established for that matrix). If not, a chemical
or physical interference effect should be
suspected.
8.3.4.2 Spiked Addition-
The recovery of a spike added to the
original sample at a minimum level of 10
times the instrumental detection limit (maxi-
mum 100 times) should be within 85 to 115
percent or within the established control limit
for that matrix If not, a matrix effect should
be suspected. The use of a standard addition
analysis procedure can usually compensate for
this effect.
CAUTION: The standard additions technique
does not detect coincident spec-
tral overlap (usually only a
factor in ICP determinations). If
overlap is suspected, the use of
computerized compensation, an
alternative wavelength, or com-
parison with an alternative method
is recommended.
8.3.4.3 Comparison with Alternative
Method of Analysis-
When investigating a new sample matrix,
a comparison test may be performed with
other analytical techniques such as atomic
absorption spectrometry or other approved
methodology.
8.3.4.4 Wavelength Scanning of
Analyte Line Region-
If the appropriate equipment is available,
wavelength scanning can be performed to
detect potential spectral interferences.
8.4 Safety
Wear protective clothing (laboratory coat
and gloves) and safety glasses. When pre-
paring reagents, especially when concentrated
acids and bases are used, special care should
be exercised. The use of concentrated hydro-
chloric acid and nitric acid should be restricted
to a hood. Many metal salts are extremely
toxic and may be fatal if swallowed. Wash
hands thoroughly after handling.
Follow the safety precautions of the
manufacturer when operating instruments.
Follow good laboratory practices when
handling compressed gases. Cylinders should
be chained or bolted in an upright position.
8.5 Apparatus and Equipment
8.5.1 Determinations by Atomic
Absorption
• Spectrophotometer, single- or dual-
channel, single- or double-beam instru-
ment with grating monochromator,
photomultiplier detector, adjustable
slits, a wavelength range of 190 to 800
nm, provisions for interfacing with a
strip chart recorder.
• Burner, as recommended by the in-
strument manufacturer. When nitrous
oxide is used as the oxidant, a nitrous
oxide burner is required.
• Hollow cathode lamps, single element
lamps preferred; multielement lamps
may be used. Electrodeless discharge
lamps may be used when available.
• Strip chart recorder.
8.5.2 Determination by Inductively
Coupled Plasma
• Inductively Coupled Plasma-Atomic
Emission Spectrometer.
8.5.3 Determination by Flame
Photometry
• Flame photometer, direct-reading or
internal-standard type; or an atomic
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absorption spectrometer operated in
the flame emission mode.
8.6 Reagents and Consumable
Materials
Water used for preparing or diluting
reagents, standards, or samples must meet
purity specifications for Type II Reagent Wa-
ter given in ASTM D 1193 (ASTM, 1984). Acids
used in the preparation of standards and for
sample processing must be ultra-high purity
grade, e.g., Baker Ultrex grade or SeaStart
Ultrapure grade. To minimize pickup of cat-
ions in standard solutions, store solutions in
linear or high density polyethylene bottles.
Use small containers to reduce the amount of
dry element that may be picked up from the
bottle walls when the solution is poured.
Shake each container thoroughly to wash
accumulated salts from walls before pouring
solution.
8.6.1 Determination by A tomlc
Absorption
• Hydrochloric acid, concentrated (12M
HCI)-Ultrapure grade (Baker Instra-
Analyzed or equivalent).
• HCI (1 percent v/v)~Add 5 mL concen-
trated HCI to 495 mL water.
• Nitric acid, concentrated-Ultrapure
grade, Baker Instra-Analyzed or e-
quivalent.
• Nitric Acid (0.5 percent v/v HNOJ--
Add 0.50 ml HNO3 to 50 mL DOI
water and dilute to 100 mL
• Primary standard solutions-Prepare
from ultra-high purity grade chemicals
as directed in the individual proce-
dures. Commercially available stock
standard solutions may also be used.
• Dilute calibration standards-Prepare
a series of standards of the cation by
dilution of the appropriate stock metal
solution in the specific matrix to cover
the concentration range desired.
Prepare all calibration standards in
concentration units of mg/L
• Fuel-Commercial grade acetylene is
generally acceptable.
• Oxidant-Air may be supplied from a
compressed-air line, a laboratory
compressor, or from a cylinder of
compressed air. Nitrous oxide is
supplied from a cylinder of com-
pressed gas.
8.6.2 Determination by
Inductively Coupled Plasma
• Hydrochloric acid, concentrated (12 M,
specific gravity 1.19) Ultrapure grade.
• Hydrochloric acid (50 percent v/v)-
Add 500 mL concentrated HCI to 400
mL DDI water and dilute to 1.00 L
• Nitric acid, concentrated (specific
gravity 1.41)-Ultrapure grade.
• Nitric acid (50 percent v/v)-Add 500
mL concentrated HNO3 to 400 mL DDI
water and dilute to 1 L.
• Primary standard solutions-May be
purchased or prepared from ultrahigh
purity grade chemicals or metals.
All salts must be dried for 1 hour at
105 °C unless otherwise specified.
CAUTION: Many metal salts are extremely
toxic and may be fatal if swal-
lowed. Wash hands thoroughly
after handling.
(1) Calcium stock standard solution
(100 mg/L)-Suspend 0.2498 g
CaCO3 (dried at 180 °C for 1 hour
before weighing) in DDI water and
dissolve cautiously with a minimum
amount of 50 percent HNO3. Add
10.0 mL concentrated HNO3 and
dilute to 1,000 mL with DDI water.
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(2) Magnesium stock standard solution
(100 mg/L)-Dissolve 0.1658 g MgO
in a minimum amount of 50 percent
HNO3. Add 10.0 ml_ concentrated
HNO3 and dilute to 1,000 mL with
DDI water.
(3) Sodium stock standard solution
(100 mg/L)~Dissolve 0.2542 g NaCI
dried at 140 °C in 0.1N NH4CI or
0.1N NH4OAc, add 10.0 mL concen-
trated HNO3 and dilute to 1,000 mL
with DDI water.
8.6.3 Determination by Flame
Photometry
• Sodium stock standard solution (1,000
mg/L)--Dissolve 2.542 g NaCI dried at
140 °C and dilute to 1,000 mL with
DDI water.
• Intermediate sodium solution (100
mg/L)-Dilute 10.00 mL stock sodium
solution with 1.0 N NH4CI or 1.0 N
NH4OAc, as needed to match sample
extract matrix, to 100.0 mL Use this
intermediate solution to prepare cali-
bration curve in sodium range 1 to 10
mg/L
• Standard sodium solution (10 mg/L)-
Dilute 10.00 mL intermediate sodium
solution with 1.0 N NH4CI or 1.0 N
NH4OAc, as needed to match sample
extract matrix, to 100 mL. Use this
solution to prepare calibration curve in
sodium range of 0.1 to 1.0 mg/L.
• Potassium stock standard solution
(1,000 mg/L)»Dissolve 1.907 g KCI
dried at 110 °C and dilute to 1,000 mL
with DDI water.
• Intermediate potassium solution (100
mg/L)-Dilute 10.0 mL stock potassium
solution with 1.0 N NH4CI or 1.0 N
NH4OAc, as needed to match sample
extract matrix, to 100 mL Use this
solution to prepare calibration curve in
potassium range of 1 to 10 mg/L.
• Standard potassium solution (10
mg/L)-Dilute 10.0 mL intermediate
potassium solution with 1.0 N NH4CI
or 1.0 N NH4OAc, as needed to match
the sample extract matrix, to 100 mL
Use this solution to prepare calibra-
tion curve in potassium range of 0.1
to 1.0 mg/L.
• Standard Lithium Solution-Use either
lithium chloride (LiCI) or lithium nitrate
(LiNOj) to prepare standard lithium
solution containing 1,000 mg Li/L.
Dry LiCI overnight in an oven at 105
°C. Rapidly weigh 6.109 g LiCI
and dissolve in 1.0 N NH4CI or
1.O N NH4OAc, as needed to match
the sample extract matrix Dilute to
1,000 mL with the same 1.0 N NH4+
solution.
Dry LiNO3 overnight in an oven at 105
°C. Rapidly weigh 9.935 g LiNO3 and
dissolve in 1.0 N NH4CI or 1.O N
NH4OAc, as needed to match the
sample extract matrix. Dilute to 1,000
mL with the same 1.0 N NH4+ solution.
Prepare a new calibration curve when-
ever the standard lithium solution is
changed. Where circumstances war-
rant, alternatively prepare a standard
lithium solution containing 2,000 mg
or even 5,000 mg Li/L.
8.7 Sample Handling,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labo-
ratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the analytical laboratory, all samples are
kept sealed and are refrigerated at 4 °C when
not being used.
For the determination of trace elements,
contamination and loss are of prime concern.
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Dust in the laboratory environment, impurities
in reagents, and impurities on laboratory ap-
paratus which the sample contacts are all
sources of potential contamination. Sample
containers can introduce either positive or
negative errors in the measurement of trace
elements by (a) contributing contaminants
through leaching or surface desorption and (b)
by depleting concentrations through adsorp-
tion. Thus the collection and treatment of the
sample prior to analysis requires particular
attention.
Labware should be thoroughly washed
as described in Section 2.3. All sample solu-
tions should be kept sealed and refrigerated
at 4 °C when not being used.
8.8 Calibration and
Standardization
Within each class of instruments (AA,
ICP, and flame photometer), the calibration
procedure varies slightly. Calibrate by analyz-
ing a calibration blank and a series of at least
three standards within the linear range. If an
ICP is used, a multielement standard may be
prepared and analyzed. For AA and flame
photometric determinations, the instrument
must be calibrated for each analyte by using
a separate standard.
The concentration of standards should
bracket the expected sample concentration;
however, the linear range of the instrument
should not be exceeded. An alternative less
sensitive resonance line may be used, but the
standards still must bracket the samples.
When indicated by the matrix spike
analysis, the analytes must be quantified by
the method of standard additions. In this
method, equal volumes of sample are added to
a deionized water blank and to three stan-
dards that contain different known amounts of
the test element. The volume of the blank and
of each standard must be the same. The
absorbence or emission of each solution is
determined and is then plotted on the vertical
axis of a graph, with the concentrations of the
known standards plotted on the horizontal
axis. When the resulting line is extrapolated to
zero absorbence or emission, the point of
intersection of the abscissa is the concentra-
tion of the unknown. The abscissa on the left
side of the ordinate is scaled the same as on
the right side but in the opposite direction
from the ordinate. An example of a plot so
obtained is shown in Figure 8-1. The method
of standard additions can be very useful;
however, for the results to be valid, the
following limitations must be taken into
consideration:
Absorbance or.
Emission
Zero Absorbance/
Emission
Concentration
Cone, of AddnO Addn 1 Addn 2 Addn 3
Sample No Addn Addn of 60% Addn of 100% Addn of 150%
of Expected of Expected of Expected
Amount Amount Amount
Figure 8-1. Standard addition plot.
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• The absorbance plot of sample and
standard must be linear over the
concentration range of concern. For
best results, the slope of the plot
should be nearly the same as the
slope of the aqueous standard curve.
If the slope is significantly different
(more than 20 percent), caution should
be exercised.
• The effect on the interference should
not vary as the ratio of analyte con-
centration to sample matrix changes,
and the standard addition should
respond in a similar manner as the
analyte.
• The determination must be free of
spectral interference and must be
corrected for nonspecific background
interference.
8.9 Quality Control
In addition to the QC inherent in the
calibration procedures, the QC procedures
described in Section 2.6 must be followed.
8.10 Procedure
General procedures for flame atomic
absorption, inductively coupled plasma, and
flame emission are given in Sections 8.10.1,
8.10.2. and 8.10.3, respectively.
& 10.1 Procedure for Determination
by Atomic Absorption
Differences among atomic absorption
spectrophotometers prevent the formulation of
detailed instructions applicable to every instru-
ment. The analyst should follow the operating
instructions for the particular instrument. In
general, after choosing the proper hollow
cathode lamp for the analysis, allow the lamp
to warm up for a minimum of 15 minutes
unless the instrument is operated in a double-
beam mode. During this period, align the
instrument, position the monochromator at the
correct wavelength, select the proper mono-
chromator slit width, and adjust the hollow
cathode current according to the recommenda-
tion of the manufacturer. Subsequently, light
the flame and regulate the flow of fuel and
oxidant, adjust the burner and nebulizer flow
rate for maximum percent absorption and
stability, and balance the photometer. Run a
series of standards of the analyte and cali-
brate the instrument. Aspirate the samples
and determine the concentrations either direct-
ly (if the instrument reads directly in concentra-
tion units) or from a calibration curve.
8.10.1.1 Determination of Dissolved
Calcium--
NOTE: Standards are made in 1.0 N NH4OAc,
1.0 N NH4CI, and 0.002 M CaCI2.
8.10.1.1.1 Preparation of Reagents-
• Lanthanum chloride (LaClg) matrix
modifier solution-Dissolve 29 g La2O3,
slowly and in small portions, in 250
mL concentrated HCI. CAUTION:
Reaction is violent. Dilute to 500 ml
with DDI water.
8.10.1.1.2 Preparation of Calcium Standard
Solutions-
• Calcium stock solution (500 mg/L Ca)
-Suspend 1.250 g CaCO3 (spectro-
scopic grade, dried at 180 °C for 1
hour before weighing) in DDI water
and dissolve cautiously with a mini-
mum of dilute HCI. Dilute to 1,000 ml
with water.
• Dilute calibration standards-Daily,
quantitatively prepare a series of
dilute Ca2* standards from the calci-
um stock solution in the correct matrix
to span the desired concentration
range. Prepare all calibration stan-
dards in concentration units of milli-
grams per liter (mg/L).
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Section 8
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Page 10 of 15
8.10.1,1.3 Suggested Instrumental Conditions
(General)~Ca\c\um hollow cathode lamp; wave-
length, 422.7 nm; fuel, acetylene; oxidant, air;
type of flame, reducing.
8.10.1.1.4 Analytical Procedure-
1. To each 10.0-mL volume of dilute
calibration standard, blank, and sam-
ple (the soil extract), add 1.00 mL
LaCI3 solution (e.g., add 2.0 mL LaCI3
solution to 20.0-mL sample).
2. Calibrate the instrument. Analyze the
samples. Dilute and reanalyze any
samples for which the concentration
exceeds the calibrated range. Record
results as mg Ca2+/L in the soil ex-
tract. (See Section 8.11.)
8.10.1.1.5 /Votes-Phosphate, sulfate, and
aluminum interfere but are masked by the
addition of lanthanum. Because low calcium
values result if the pH of the sample is above
7, standards and samples are prepared in
dilute acid solution. (NH4CI extract is some-
what acidic. NH^OAc is pH 7.0.) Concentra-
tions of magnesium greater than 1,000 mg/L
also cause low calcium values. Concentra-
tions of as much as 500 mg/L of sodium,
potassium, and nitrate cause no interference.
Anionic chemical interferences can be
expected if lanthanum is not added to samples
and standards.
A nitrous oxide-acetylene flame will
provide two to five times greater sensitivity
than an air-acetylene flame and will provide
freedom from chemical interferences. loniza-
tion interferences should be controlled by
adding a large amount of alkali, e.g., K+ or
Cs+, to the sample and standards. The analy-
sis appears to be free from chemical suppres-
sions in the nitrous oxide-acetylene flame.
The 239.9-nm line may also be used.
This line has a relative sensitivity of 120.
8.10.1.1.6 Precision and Accuracy-In a single
laboratory (EMSL-Cincinnati) evaluation using
distilled water spiked at concentrations of 9.0
and 36 mg Ca2+/L, the standard deviations
were ±0.3 and ±0.6, respectively. Recov-
eries at both these levels were 99 percent.
8.10.1.2 Determination of Dissolved
Magnesium-
8.10.1.2.1 Preparation of Reagents-
• Lanthanum chloride (LaCIJ solution-
Dissolve 29 g La2O3, slowly and in
small portions, in 250 mL concentrated
HCI. (CAUTION: Reaction is violent.)
Dilute to 500 mL with DDI water.
8.10.1.2.2 Preparation of Magnesium Standard
Solutions-
• Stock solution (500 mg/L Mg2+)»
Dissolve 0.829 g magnesium oxide
(MgO, spectroscopic grade) in 10 mL
of HNO3 and dilute to 1.00 L with DDI
water.
• Dilute calibration standards-Daily,
quantitatively prepare from the Mg2*
stock solution and in the correct
matrix, a series of Mg2* standards
that spans the desired concentration
range. Prepare all calibration stan-
dards in concentration units of milli-
grams per liter (mg/L).
8.10.1.2.3 Suggested Instrumental Conditions
(Genera/J~Magnes\um hollow cathode lamp;
wavelength, 285.2 nm; fuel, acetylene; oxidant,
air; type of flame, oxidizing.
8.10.1.2.4 Analytical Procedure-
1. To each 10.0-mL dilute calibration
standard, blank, and sample, add 1.00
mL LaCI3 solution (e.g., add 2.0 mL
LaCI3 solution to 20.0 mL sample).
2. Calibrate the instrument.
3. Analyze the samples.
4. Dilute and reanalyze any samples for
which the concentration exceeds the
linear range.
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Section 8
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Page 11 of 15
5. Record results as mg Mg2*/L in the
soil extract. (See Section 8.11.)
8.10.1.2.5 /Votes-The interference caused by
aluminum at concentrations greater than 2
mg/L is masked by addition of lanthanum.
Sodium, potassium, and calcium cause no
interference at concentrations less than 400
mg/L.
The line at 202.5 nm may also be used.
This line has a relative sensitivity of 25.
To cover the range of magnesium values
normally observed (0.1 to 20 mg/L), it is sug-
gested that either the 202.5-nm line be used or
the burner head be rotated. A 90 °C rotation
of the burner head will produce approximately
one-eighth the normal sensitivity.
8.10.1.2.6 Precision and Accuracy-ln a single
laboratory (EMSL-Cincinnati) evaluation using
distilled water spiked at concentrations of 2.1
and 8.2 mg Mg2+/L, the standard deviations
were ±0.1 and ±0.2, respectively. Recoveries at
both of these levels were 100 percent.
8.10.1.3 Determination of Dissolved
Potassium-
s'. 10.1.3.1 Preparation of Potassium Standard
Solutions-
• Potassium stock solution (100 mg/L
K) - Dissolve 0.1907 g KCI (spectro-
scopic grade, dried at 110 °C) in DDI
water and dilute to 1.00 L
• Dilute calibration standards-Daily,
quantitatively prepare in the correct
matrix a series of calibration stan-
dards spanning the desired concentra-
tion range. Prepare all calibration
standards in concentration units of
milligrams per liter (mg/L).
8.10.1.3.2 Suggested Instrumental Conditions
(General)—
• Potassium hollow cathode lamp;
wavelength, 766.5 nm; fuel, acetylene;
oxidant, air; type of flame, slightly
oxidizing.
8.10.1.3.3 Analytical Procedure-
1. Calibrate the instrument.
2. Analyze the samples.
3. Dilute and reanalyze any sample for
which the concentration exceeds the
calibrated range.
4. Record results as mg K*/L in the soil
extract. (See Section 8.11.)
8.10.1.3.4 Notes-ln air-acetylene or other high-
temperature flames (>2,800 °C), potassium
can experience partial ionization which indirect-
ly affects absorption sensitivity. The presence
of other alkali salts in the sample can reduce
this ionization and thereby can enhance ana-
lytical results. The ionization suppressive
effect of sodium is small if the ratio of Na+ to
K+ is under 10. Any enhancement because of
sodium can be stabilized by adding excess
sodium (1,000 ug/mL) to both sample and
standard solutions. If more stringent control
of ionization is required, the addition of cesi-
um should be considered. Reagent blanks
should be analyzed to correct for potassium
impurities in the buffer stock.
The 404.4-nm line may also be used.
This line has a relative sensitivity of 500.
To cover the range of potassium values
normally observed (0.1 to 20 mg/L), it is sug-
gested that the burner head be rotated. A 90
°C rotation of the burner head provides ap-
proximately one-eighth the normal sensitivity.
8.10.1.3.5 Precision and Accuracy-ln a single
laboratory (EMSL-Cincinnati) evaluation using
distilled water samples spiked at concentra-
tions of 1.6 and 6.3 mg K+/L, the standard
deviations were ±0.2 and ±0.5, respectively.
Recoveries at these levels were 103 percent
and 102 percent, respectively.
8.10.1.4 Determination of Dissolved
Sodium-
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Page 12 of 15
8.10.1.4.1 Preparation of Sodium Standard
Solutions--
• Sodium stock solution (1,000 mg/L
Na+)--Dissolve 2.542 g NaCI (spectro-
scopic grade, dried at 140 °C) in DDI
water and dilute to 1.00 L.
• Dilute calibration standards - Daily,
quantitatively prepare a series of
calibration standards in the correct
matrix spanning the desired concen-
tration range. Prepare all calibration
standards in concentration units of
milligrams per liter (mg/L).
8.10.1.4.2 Suggested Instrumental Conditions
(Genera/J~Sod\um hollow cathode lamp; wave-
length, 589.6 nm; fuel, acetylene; oxidant, air;
type of flame, oxidizing.
8.10.1.4.3 Analytical Procedure--
1. Calibrate the instrument.
2. Analyze the samples.
3. Dilute and reanalyze any samples for
which the concentration exceeds the
calibrated range.
4. Record results as mg Na+/L.
Section 8.11.)
(See
8.10.1.4.4 Notes~~n\e 330.2-nm resonance line
of sodium, which has a relative sensitivity of
185, provides a convenient way to avoid the
need to dilute more concentrated solutions of
sodium.
Low-temperature flames increase sensi-
tivity by reducing the ionization of this easily
ionized metal. Ionization may also be con-
trolled by adding potassium (1,000 mg/L) to
both standards and samples.
8.10.1.4.5 Precision and Accuracy-ln a single
laboratory (EMSL-Cincinnati) evaluation using
distilled water samples spiked at levels of 8.2
and 52 mg Na+/L, the standard deviations
were ±0.1 and ±0.8, respectively. Recoveries at
these levels were 102 percent and 100 percent.
8.10.2 Procedure for
Determinations by
Inductively Coupled
Plasma
1. Set up the instrument as recommend-
ed by the manufacturer or as experi-
ence dictates. The instrument must
be allowed to become thermally stable
before analysis begins (10 to 30
minutes).
2. Profile and calibrate the instrument
according to the recommended proce-
dures of the manufacturer. Flush the
system with the calibration blank
between each standard. The use of
the average intensity of multiple
exposures for both standardization
and sample analysis has been found
to reduce random error.
3. Begin sample analysis, flushing the
system with the calibration blank
solution between each sample. Ana-
lyze QC samples as required.
4. Dilute and reanalyze any samples for
which the concentration exceeds the
calibration range.
8.10.3 Procedure for
Determinations by Flame
Photometry
Locate instrument in an area away from
direct sunlight or constant light emitted by an
overhead fixture and in an area free of drafts,
dust, and tobacco smoke. Guard against
contamination from corks, filter paper or pulp,
perspiration, soap, cleansers, cleaning mix-
tures, and inadequately rinsed apparatus.
Because of differences among instruments, it
is impossible to formulate detailed operating
instructions. Follow recommendation of the
manufacturer for selecting proper photocell
and wavelength, for adjusting slit width and
sensitivity, for appropriate fuel and oxidant
pressures, and for the steps for warm-up,
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Page 13 of 15
correcting for interferences and flame back-
ground, rinsing of burner, igniting sample, and
measuring emission intensity.
8.10.3.1 Direct Intensity
Measurement-
Starting with the highest calibration
standard and working toward the most dilute,
measure emission at 589 nm for sodium and
766.5 nm for potassium. Repeat the opera-
tion with calibration standards and samples
enough times to secure a reliable average
reading for each solution.
8.10.3.2 Internal Standard
Measurement--
To a carefully measured volume of sam-
ple (or diluted portion), each sodium calibration
standard, and a blank, add with a volumetric
pipet an appropriate volume of standard
lithium solution. Then follow all steps pre-
scribed in 8.10.3.1 above for direct-intensity
measurement.
8.10.3.3 Bracketing Approach-
If greater precision and accuracy are
required from the calibration curve or if con-
centrations are automatically output by the
instrument, select and prepare sodium stan-
dards that immediately bracket the emission
intensity of the sample. Determine emission
intensities of the bracketing standards, i.e.,
one standard slightly less than and the other
slightly greater than the sample, and of the
sample as simultaneously as possible. Repeat
the determination on bracketing standards and
sample.
8.11 Calculations
8.11.1 Solution Concentrations
Instruments may be calibrated to output
sample or soil extract results directly in con-
centration units, i.e., mg/L. If the instrument is
not so calibrated or programmed, then either
(1) the slope of the linear calibration curve is
calculated and sample concentrations are
subsequently calculated, or (2) a manual
calibration curve is prepared and sample
concentrations are determined by comparing
the sample signal to the calibration curve.
8.11.2 Dilutions
If dilutions are performed, the appropri-
ate factor must be applied to sample values.
The dilution factor is incorporated in equations
8-1 and 8-2.
8.11.3 Flame Photometry
If analyses are performed by flame
photometry and the bracketing approach is
used, the following equation and equations
8-1, 8-2, and 8-3 (Section 8.11.4) are required to
determine meq/L:
mg analyte/L
[(B - A) (s - a) + A] D
(b-a)
where,
B = mg analyte/L in upper bracketing standard
A = mg analyte/L in lower bracketing standard
b = emission intensity of upper bracketing
standard
a = emission intensity of lower bracketing
standard
s = emission intensity of sample
mL sample + ml_ diluent
D = dilution ratio =
mL sample
8.11.4 Atomic Absorption or
Inductively Coupled Plasma
To convert mg/L to meq/L, multiply mg/L
times 0.0256 for K+ or by 0.0435 for Na+.
After the meq/L values are obtained,
calculate and report results in the original soil
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Section 8
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Page 14 of 15
sample on an oven-dried (OD) basis by using
the following equation:
analyte concentration in soil (meq/100g)
'analyte cone.
in extract
(meq/L)
ODsoil
^sample wt
where,
extract \/dilution\
volume mLV factor \ (100)
lif needed I
1,000 mUL A /
(8-1)
extract volume ml
weight of extract
in reservoir tube (g)
density of extraction
solution (g/cm3)
NOTE: Density of 1.0 N NH.OAc = 1.0124 g/cm
NH.CI = 1.0105 g/cm3
(8-2)
'3 1.0 N
and,
grams oven-
dried (OD) =
sample
1100-
i moisture
content
100
vt air-dried \
soil in g I
(8-3)
Values should be reported to the nearest 0.001 meq.
8.12 Precision and Accuracy
The precision and accuracy information
provided is based on analysis of water sam-
ples (U.S. EPA, 1983; APHA et al., 1985) and
various types of waste samples (Patel et al.,
1984). Analysis of soil extracts, which have
different matrices and reflect different sample
preparation procedures, may not supply results
of the same precision and accuracy as cited
here. The information in this section is sup-
plied only as an indicator.
& 12.1 Determination by A tomic
Absorption
Precision and accuracy for the instrumen-
tal portion of the procedure only were reported
in the cation-specific discussions in sections
8.10.1.1.6 (Ca2+), 8.10.1.2.6 (Mg2+), 8.10.1.3.5
(fC), and 8.10.1.4.5 (Na+).
8.12.2 Determinations by
Inductively Coupled Plasma
Precision and accuracy for synthetic
standards prepared in distilled water are not
available for the analytes of interest (Ca2+,
Mg2+, and Na*). The only precision and accu-
racy results available are for analysis of waste
samples (Patel et al., 1984). It is not known
how closely these results relate to those for
soil sample extracts. The results (see Table
8-4) should not be compared to those by AA or
flame photometry, however, because the
matrices of the samples are not the same.
Table 8-4. Precision and Accuracy Data for
Inductively Coupled Plasma (Patel
et al., 1984)
Ca2+
Mg2+
Na+
Precision
(% RSD)
7.00
6.62
5.98
Accuracy
(% Recovery)
105.0
100.5
123.7
8.12.3 For Determinations by
Flame Photometry
A synthetic sample containing 19.9 mg
Na+/L, 108 mg Ca2+/L, 82 mg Mg2+/L, 3.1 mg
K+/L, 241 mg CI'/L, 0.25 mg NOjT-N/L, 1.1 mg
NOg-N/L, 259 mg SO^/L, and 42.5 mg total
alkalinity/L was analyzed in 35 laboratories by
the flame photometric method, with %RSD of
17.3 and a relative error of 4.0 percent for
solution determinations. A %RSD of 15.5 and
a relative error of 2.3 percent were calculated
for potassium determinations.
8.13 References
American Public Health Association, American
Water Works Association, and Water
Pollution Control Federation. 1985.
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Section 8
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Page 15 of 15
Standard Methods for the Examination of
Water and Waste water, 16th Ed. APHA, Wash-
ington, D.C.
American Society for Testing and Materials.
1984. Annual Book of ASTM Standards,
Vol. 11.01, Standard Specification for
Reagent Water, D1193-77 (reapproved
1983). ASTM, Philadelphia, Pennsylvania.
Blume, L J., M. A. Papp, K. A. Cappo, J. K.
Bartz, and D. S. Cof f ey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. U.S.
Environmental Protection Agency, Las
Vegas, Nevada. In: Direct/Delayed
Response Project Southern Blue Ridge
Province Field Sampling Report: Vol. I
Field Sampling. U.S. Environmental
Protection Agency.
Fassel, V. A 1982. Analytical Spectroscopy
with Inductively Coupled Plasmas -
Present Status and Future Prospects.
In: Recent Advances in Analytical Spec-
troscopy. Pergamon Press, New York,
New York.
Patel, B. R., G. A. Raab, D. Cardenas, and T.
W. Riedy. 1984. Report on a Single-
Laboratory Evaluation of Inductively
Coupled Plasma Optical Emission Meth-
od 6010. U.S. Environmental Protection
Agency, Las Vegas, Nevada.
U.S. Environmental Protection Agency. 1983
(revised). Methods for Chemical Analysis
of Water and Wastes, Method 200.0,
Atomic Absorption Methods; and Method
200.7, Inductively Coupled Plasma-Atomic
Emission Spectrometric Method for the
Trace Element Analysis of Water and
Wastes. EPA 600/4-79-020. U.S. Environ-
mental Protection Agency, Cincinnati,
Ohio.
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Section 9
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Page 1 of 7
9 Exchangeable Acidity
9.1 Scope and Application
Exchangeable acidity refers to the hydro-
gen and aluminum ions held on soil colloids
rather than to those ions present in the soil
solution (active acidity). Because the ions
migrate from the colloids to the soil solution
when the pH is reduced, the conditions under
which exchangeable acidity is quantitatively
determined must be defined carefully.
The method most frequently used to
determine exchangeable acidity and recom-
mended by Fernandez (1983) involves treat-
ment of the soil sample with a barium chloride
(BaCy solution buffered to pH 8.2 followed by
titration of the extracted solution. This method
actually measures total potential acidity, not
the exchangeable acidity that actually occurs
in field soils. Determination of exchangeable
acidity by treatment of the soil sample with a
solution of a neutral salt (KCI) and followed by
subsequent titration of the extracted solution
may be more indicative of actual field acidity.
Methods for both BaCI2- and KCI-exchangeable
acidity are provided here, but the former is
performed primarily to allow comparison with
already existing data.
The KCI extract obtained from this proce-
dure is analyzed for aluminum, as well as for
exchangeable acidity, because the aluminum
species that is extracted by the KCI solution is
the species most likely to be toxic to fish and
plants.
9.2 Summary of Method
Exchangeable acidic ions are extracted
from two portions of a soil sample. One of the
extractions is with a BaCI2 extracting solution,
and the other is with a KCI extracting solution.
The extracts are then titrated, and the results
are expressed as milliequivalents exchangeable
acidity per 100 g soil. These extraction and
titration procedures are performed with auto-
mated equipment. This method is modified
from Thomas (1982) and USDA/SCS (1984).
The KCI extract is also analyzed for
aluminum by inductively coupled plasma atom-
ic emission spectrometry (ICP). This instru-
mental technique is summarized in Section
8.2.2.
9.3 Interferences
No specific interferences are identified
for the extraction and titration procedures; use
of automated equipment minimizes effects of
variation in technique. Interferences influenc-
ing the determination of aluminum by ICP are
described in Section 8.3.
9.4 Safety
Wear protective clothing (laboratory coat
and gloves) and safety glasses when prepar-
ing reagents, especially when concentrated
acids and bases are used. The use of concen-
trated acids and ammonium hydroxide solu-
tions should be restricted to a hood.
Follow the safety precautions provided
by the manufacturer when operating the
instruments.
Follow good laboratory practices when
handling compressed gases. Cylinders should
be chained or bolted in an upright position.
9.5 Apparatus and Equipment
9.5.1 General
• Mechanical extractor, 24 place, manu-
factured by Centurion, Inc. (Figure
7-1).
• Syringes, 60 ml_, one sample tube and
one extraction syringe per sample.
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Section 9
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Page 2 of 7
• Stirring rods, glass; one per sample.
• Pipettors, 2, volume adjustable to 25
ml.
• Filter pulp, Schleicher and Schuell, No.
289, washed according to the proce-
dure given in Section 2.4.
• Erlenmeyer flasks, 250 ml_ and 125
• Reciprocating shaker.
• Tubes, glass, 25 ml, centrifuge or
culture, with caps.
• Eppendorf or equivalent pipet, 5 mL
with disposable plastic tips.
• Eppendorf or equivalent pipet, 5 pL
with disposable plastic tips.
• Volumetric flasks, volumes as needed.
• Bottles, polyethylene (LPE), 25 mL,
optional.
• Automatic titrator.
• pH meter and electrode.
• Fleakers.
9.5.2 Instrumentation for
Determination by ICP
• Inductively coupled plasma atomic
emission spectrometer, computer-
controlled, with background correc-
tion capability.
9.6 Reagents and Consumable
Materials
• Ascarite.
• Buffer solution (0.5 N BaCI2/0.2 N
N(CH2CH2OH)3)»Dissolve 61.07 g
BaCI2»2H2O and 29.8 g triethanola-
mine (TEA) in 1.00 L C02-free, DDI
water. Adjust pH to 8.2 with 10 per-
cent HCI. Protect solution from C02
contamination by attaching a drying
tube containing Ascarite to the air
intake of the storage vessel.
• Replacement solution (0.5 N with re-
spect to BaCI2)-Dissolve 61.07 g
BaCI2-2H20 with 5 mL of above
BaCI2-TEA buffer solution and dilute
to 1.00 L with DDI water.
• Hydrochloric acid, concentrated (12
M HCI)-Ultrapure grade (Baker In-
stra-Analyzed or equivalent).
• Hydrochloric acid (1 percent v/v)~
Add 5 mL concentrated HCI to 495
mL DDI water.
• Hydrochloric acid (0.1 N, standar-
dized)~Dilute 8.32 mL concentrated
HCI to 1.00 L with DDI water. Stan-
dardize as described in Section
7.6.2. This may also be purchased
as certified, standardized 0.1 N HCI.
• Potassium chloride replacement
solution (1.0 ISO-Dissolve 74.56 g KCI
in water and dilute to 1.00 L.
• Sodium hydroxide (NaOH), pellets or
flakes.
• Sodium hydroxide (5 percent wt/vol)
-Dissolve 50 g NaOH in DDI water
and dilute to 1.000 L. This disso-
lution generates heat; therefore, a
water- or ice-bath should be used to
cool the dissolution vessel.
• Sodium hydroxide (0.01 N, standard-
ized)-Dilute 6 to 7 mL of 5 percent
NaOH to 1.00 L with CO2-free DDI
water. Titrate 20.00 mL with the 0.1
N standardized HCI titrant to a
methyl orange endpoint (pH » 4.4).
• Methyl orange solution, 0.1 percent
aqueous solution-Dissolve 0.10 g
methyl orange in 100 mL DDI water.
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Section 9
Revision 2
Date: 12/86
Page 3 of 7
9.7
• Sulfuric acid, concentrated-Ultra-
pure grade.
• Nitric acid, concentrated-Ultrapure
grade.
• Nitric acid (0.5 percent v/v HNO3
Ultrapure grade)-Add 1 ml concen-
trated HNO3 to DDI water and dilute
to 200 ml.
• Primary aluminum standard.
• Dilute calibration standards-Prepare
a series of aluminum standards to
cover the concentration range de-
sired by dilution of the primary alu-
minum standard. Prepare all cali-
bration standards in concentration
units of milligrams per liter (mg/L).
• NBS-traceable pH buffers of pH = 4,
pH = 7, and pH = 10, for electrode
calibration.
Sample Collection,
Preservation, and Storage
Sample collection is discussed in
Blume et al. (1987). No preservatives are
added to the samples. Within 24 hours of
collection, samples are delivered to the prep-
aration laboratory and are refrigerated at 4
°C. If this time requirement cannot be met,
the samples are placed in a cooler after they
are collected. In the laboratory, all samples
are kept sealed and are refrigerated at 4 °C
when not is use.
9.8 Calibration and
Standardization
9.8.1 Titration
Calibrate the titrator for volume of so-
lution delivered. Calibrate the pH electrode
by using two pH buffers that bracket the
desired endpoint. (Refer to Section 6.8 for
general information.)
9.8.2 Determination of Aluminum
Calibrate the instrument for aluminum
by analyzing a calibration blank and a series
of at least three standards within the linear
range. Follow the instructions in the instru-
ment operating manual. The concentration
of standards should bracket the expected
sample concentration; however, the linear
range of the instrument should not be ex-
ceeded.
9.8.3 Method of Standard
Additions for Determination
of Aluminum
Aluminum may be quantified by the
method of standard additions. (Note: It is
difficult to maintain a stable, concentrated
solution of AI3+ for performing matrix spikes
or standard additions.)
In this method, equal volumes of sam-
ple are added to a DDI water blank and to
three standards that contain different known
amounts of aluminum. The volume of the
blank and of each standard must be the
same. The emission of each solution is
determined and is then plotted on the vertical
axis of a graph, with the concentrations of
the known standards plotted on the horizon-
tal axis. When the resulting line is extrapo-
lated to zero absorbance, the point of inter-
section of the abscissa is the concentration
of the unknown. The abscissa on the left
side of the ordinate is scaled the same as
on the right side but in the opposite direction
from the ordinate. An example of a plot so
obtained is shown in Figure 8-1. The method
of standard additions can be very useful;
however, for the results to be valid, the fol-
lowing limitations must be taken into consid-
eration:
• The emission plot of sample and
standard must be linear over the
concentration range of concern. For
best results, the slope of the plot
should be nearly the same as the
slope of the aqueous standard
curve. If the slope is significantly
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different (more than 20 percent),
caution should be exercised.
• The effect on the interference should
not vary as the ratio of analyte con-
centration to sample matrix changes,
and the standard addition should
respond in a simitar manner as the
analyte.
• The determination must be free of
spectral interference and must be
corrected for nonspecific background
interference.
9.9 Quality Control
QC procedures are specified in Section
2.6.
1. For the exchangeable acidity titra-
tion, three reagent blanks must be
processed for each of the two ex-
traction procedures. The average
titration result for each kind of blank
is subtracted from results for the
samples in the same matrix Ma-
trix spikes and QCCS are not re-
quired for this titration.
2. For the aluminum determination, in
addition to the QC inherent in the
calibration procedures for ICP, three
reagent blanks must be processed
as described in Section 9.10.2. A
detection limit QC sample and QCCS
are required as described in Section
2.6.
9.10 Procedure
9. 10. 1
9.10.1.1
Barium Chloride
Method
Preparation of Sample
Tubes-
Tightly compress a 1-g ball of filter pulp
into the bottom of a syringe barrel with a
modified plunger. (To modify the plunger,
remove the rubber portion and cut off the
plastic protrusion.) Tamp the plunger and
syringe assembly on a tabletop several
times.
9.10.1.2 Preparation of Mineral
Soils-
1. Weigh air-dried sample, equivalent to
2.00 g oven-dried soil, into tube.
Place sample tube in upper disc of
extractor and connect to inverted
extraction syringe, the plunger of
which is inserted in the slot of the
stationary disc of the extractor. At-
tach pinch clamp to delivery tube of
syringe barrel.
2. Add 10 mL BaCI2-TEA buffer solution
to sample. Stir the sample mixture
with a glass stirring rod for 10 sec-
onds. Leave stirring rod in syringe.
Allow sample to stand for 30 min-
utes.
3. After 30 minutes, set extractor for a
30-minute rate and extract until 0.5
to 1.0 cm of solution remains above
each sample. If necessary, turn off
extractor to prevent soil from be-
coming dry. Continue at 9.10.1.5.
9.10.1.3 Preparation of Organic
Soils-
1. Weigh air-dried sample, equivalent to
approximately 2.00 g oven-dried soil,
into small glass tube. Add 5 mL
BaCI2-TEA buffer solution to the
sample, cap, and shake the tube
and contents for 1 hour on a recipro-
cating shaker. Some organic soils
have very high acidity, which may
require reducing the amount of soil
to 1.00 g to stay in the midrange of
the titration procedure.
2. Place sample tube in upper disc of
extractor and connect to inverted
extraction syringe, with the sy-
ringe plunger inserted in the slot of
the stationary disc of the extractor.
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Attach pinch clamp to delivery tube
of syringe barrel.
3. Quantitatively transfer contents of
small glass tube to sample tube
with 5 mL buffer solution. Set ex-
tractor at the 30-minute extraction
rate and extract until only a small
volume of solution remains above
the sample.
9.10.1.4 Preparation of Reagent
Blanks-
1. Run three reagent blanks for each
batch of actual samples.
2. Place prepared sample tube in up-
per disc of extractor and connect to
inverted extraction syringe, the plun-
ger of which is inserted in the slot
of the stationary disc of the extrac-
tor.
3. Add 10 mL BaCI2-TEA buffer solution
as described for mineral soils in
Section 9.10.1.2, step 2. Continue
with sections 9.10.1.2, step 3 and
9.10.1.5.
9.10.1.5 Principal Extraction-
Add a second 10-mL aliquot of BaCI2-
TEA buffer solution and continue extracting
until nearly all solution has been pulled
through sample. Add replacement solution
from pipettor in two 20-mL aliquots, passing
the first aliquot through the sample before
adding the next. Total time for replacement
should be approximately 30 minutes. Quanti-
tatively transfer extract to an Erlenmeyer
flask.
9.10.1.6 Titration-
1. Add 100 mL water to extract in
Erlenmeyer flask. Use an automatic
titrator to titrate with 0.1 N HCI to
an endpoint pH of 4.60.
2. Titrate three reagent blanks, each
containing 20 mL buffer solution and
40 mL replacement solution and
extracted through 1 g of filter pulp,
as described above for one batch of
actual samples.
9.10.2 Potassium Chloride (KCI)
Method
9.10.2.1 Preparation of Sample
Tubes-
Tare each extraction syringe. Tightly
compress a 1-g ball of filter pulp into the
bottom of a syringe barrel with a modified
plunger. (To modify the plunger, remove the
rubber portion and cut off the plastic protru-
sion.) Tamp the plunger and syringe assem-
bly on a tabletop several times.
9.10.2.2 Preparation of Mineral
Soils-
1. Weigh air-dried sample, equivalent to
2.5 g oven-dried soil, into tube.
Place sample tube in upper disc of
extractor and connect to inverted,
tared extraction syringe, the plunger
of which is inserted in the slot of
the stationary disc of the extractor.
2. Add a 10-mL aliquot of KCI replace-
ment solution to sample. Mix for
10 seconds with a glass stirring
rod. Leave stirring rod in syringe.
Allow sample to stand for 30 min-
utes, then extract at a 30-minute
rate until 0.5 to 1.0 cm of solution
remains above each sample. If nec-
essary, turn off extractor to prevent
soil from becoming dry. Continue at
9.10.2.5.
9.10.2.3 Preparation of Organic
Soils-
1. Weigh air-dried sample, equivalent to
2.50 g oven-dried soil, into small
glass tube. Add 6 mL KCI replace-
ment solution, cap, and shake the
tube and contents on a reciprocating
shaker for 1 hour.
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If necessary, the sample weight may
be reduced by half without changing
the remaining procedure.
2. Place sample tube in upper disc of
extractor and connect to inverted,
tared extraction syringe, the plunger
of which is inserted in the slot of
the stationary disc of the extractor.
3. Quantitatively transfer sample and
solution to a sample tube with 4 mL
KCI replacement solution. Extract at
a 30-minute rate until 0.5 to 1.0 cm
of solution remains above each
sample.
9.10.2.4 Preparation of Reagent
Blanks--
1. Run three reagent blanks for each
batch of actual samples.
2. Place prepared sample tube in upper
disc of extractor and connect to in-
verted extraction syringe, the
plunger of which is inserted in the
slot of the stationary disc of the
extractor.
3. Add KCI replacement solution as
described for mineral soils in Section
9.10.2.2., i.e., add 10 mL KCI replace-
ment solution. Allow syringe to
stand for 30 minutes, then extract at
a 30-minute rate until 0.5 to 1.0 cm
solution remains above the filter
pulp. If necessary, turn off extractor
to prevent filter pulp from becoming
dry. Continue at 9.10.2.5.
9.10.2.5 Principal Extraction--
Turn off extractor and add 40 mL KCI
replacement solution to the reservoir syringe.
Extract at a 40-minute rate. Disconnect
syringes from sample tube, leaving rubber
connector on sample tube, and weigh each
syringe containing the extract to the nearest
0.01 g. The density factor to convert solution
weight to volume is 1.0412 g/cm3.
9.10.2.6 Removal of Aliquot for
Aluminum Determination-
NOTE: Take each sample solution through
this step before proceeding to the
next sample.
Transfer the solution in the recovery
syringe to a 125-mL Erlenmeyer flask but do
not rinse the syringe at this time. With a
plastic-tipped, fixed-volume pipet, transfer a
5-mL aliquot of the solution in the Erlenmeyer
flask to another vessel and immediately acid-
ify the aliquot by adding 5 juL of concentra-
ted sulfuric acid. Complete the quantitative
transfer of the solution from the recovery
syringe to the Erlenmeyer flask, i.e., rinse the
syringe with DOI water and add the rinsings
to the solution in the flask. To determine
KCI-exchangeable aluminum in the acidified
5-mL aliquot, continue at Section 9.10.3; to
determine the exchangeable acidity of the
solution in the Erlenmeyer flask, continue at
Section 9.10.2.7.
9.10.2.7 Titration-
1. To the solution in the Erlenmeyer
flask, add 2 or 3 drops of phenol-
pthalein indicator. Using an automat-
ic titrator, titrate with 0.01 N NaOH
to the first permanent pink endpoint,
pH « 8.4.
Note: At the endpoint, it takes approxi-
mately 0.10 mL to go from pH =
8.0 to pH = 8.3. A deep pink is
too far.
2. Titrate three reagent blanks, each
containing 45 mL KCI replacement
solution and extracted through 1 g
of filter pulp as described above,
for one batch of actual samples.
9.10.3 Determination of
Aluminum
Determine aluminum by inductively
coupled plasma (see Section 8.10.2). If
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necessary, dilute sample to stay within linear
dynamic range specified for the instrument.
9.11 Calculations
1. Calculate exchangeable acidity for
the barium chloride method by using
the following equation:
Exchangeable acidity (meq/100 g) =
^Reagent-blank Sample \ / \
titer(mL) - titer (mL) \/Normality \
I of I
oven-dried soil wt (g) / \ HCI /
(100)
(9-1)
Establish the blank titer by taking the mean of
the titrations of three reagent blanks (see Section
9.10.2.7).
2. Calculate exchangeable acidity for the po-
tassium chloride method as follows:
Exchangeable
acidity =
(meq/100 g)
(Normality |
I of
/Sample Reagent-blank \
titer (mL) - titer (mL) 1
oven-dried soil wt (g)
'
total
volume
total
.volume - 5mL>
(100)
(9-2)
Again establish the blank titer by taking the
mean of the titrations of three reagent blanks (see
Section 9.10.2.7). The density factor to convert KCI
solution weight to volume is 1.0412 g/cm'.
3. Calculate
follows:
Extractable AI3+
(meq/100 g)
3 meq AI3+
KCI-extractable aluminum as
mg AI3+/L
9.12 Precision and Accuracy
Precision and accuracy information is
not available for the exchangeable acidity
determinations. The precision and accuracy
information that is available for determina-
tion of aluminum by ICP is given in Section
10.12.
9.13 References
Blume, L J., M. L Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil
Sampling Manual for the Direct/Delayed
Response Project Soil Survey, U.S. Envi-
ronmental Protection Agency, Las
Vegas, Nevada. Appendix A In:
Direct/Delayed Response Project South-
ern Blue Ridge Province Field Sampling
Report. Vol. I: Field Sampling. U.S.
Environmental Protection Agency.
Fernandez, I. 1983. Field Study Program Ele-
ments to Assess the Sensitivity of Soils
to Acidic Deposition Induced Alter-
ations in Forest Productivity. Technical
Bulletin No. 404. National Council of
the Paper Industry for Air and Stream
Improvement, Inc.. New York, New
York.
Thomas, G. W. 1982. Exchangeable Cations,
pp. 159-165. In: Methods of Soil Analy-
sis: Part 2 - Chemical and Microbiolog-
ical Properties, Second Edition, A. L.
Page, R. H. Miller, and D. R. Keeney
(eds.). American Society of Agronomy,
Inc./Soil Science Society of America,
Inc., Madison, Wisconsin.
loven-dried soil wt (g) /
1 L \ /total volumeX
26.9815 mg Al / \ 1.000 mL
of
extract
/dilution f actor X
\needed /
(100)
(9-3)
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10 Lime and Aluminum Potential
10.1 Scope and Application
Lime and aluminum potential are related
to the concentrations of Ca2+ and AI3+, respec-
tively, that are extracted from a soil sample by
a dilute CaCI2 solution. Lime potential is
defined as pH - 1/2 pCa. The p-function is
defined as the negative logarithm (base 10) of
the molar concentration of that species, or:
pX = - log [X]. The advantage of using the
p-function is that concentration information is
available in terms of small positive numbers.
Aluminum potential, KA> is defined as: KA = 3
pH - pAI. Extractable Mg2+, K+, and Na+ are
also determined for comparison to amounts
determined in the CEC extracts. Fe3+ and AI3+
are determined for comparison to amounts
obtained by the extractable iron and aluminum
procedures in Section 11.
The procedure involves automated extrac-
tion of soil with 0.002 M CaCI2 in a 1:2 ratio for
mineral soils and in a 1:10 or 1:25 ratio for
organic soils. The extract is analyzed by
atomic absorption (AA) or inductively coupled
plasma (ICP) emission for Ca2+, Mg2+, Na+,
and Fe3+, by ICP for AI3+, and by AA for K+.
Flame atomic emission (flame photometry)
may be used for K+ and Na*.
Performance data such as instrumental
detection limits are given in Section 8.1 for
Ca2+, Mg2+, Na+ and K+ determinations. For
Fe3+ and AI3+ determinations, the information
in Tables 10-1 and 10-2 applies.
Table 10-2. Recommended Wavelengths and
Estimated Instrumental Detection Limits
for Determination of Fe3+ and AI3+ by
Inductively Coupled Plasma
Element
Wavelength*
(nm)
Estimated Detection Limit
Iron
Aluminum
258.950
308.215
45
8 The wavelengths listed are recommended because of
their sensitivity and overall acceptance. Other wave-
lengths may be substituted if they can provide the
needed sensitivity and if they are treated with the
same corrective techniques for spectral interference.
b The estimated instrumental detection limits as shown
are taken from Fassel, 1982. They are given as a guide
for an instrumental limit. The actual method detection
limits are sample-dependent and may vary as the
sample matrix varies.
10.2 Summary of Method
The procedure involves automated extrac-
tion of soil with 0.002 M CaCI2. The soil-to-
solution ratio is 1:2 for mineral soils and is
1:10 or 1:25 for organic soils. The extract is
analyzed by atomic absorption (AA) or induc-
tively coupled plasma (ICP) emission for Ca2+,
Mg2+, Na+, and Fe3+, by ICP for AI3+, and by
AA for K+. Flame atomic emission (flame
photometry) may be used to analyze for K+
and Na+. These instrumental analytical tech-
niques are summarized in Section 8.2.
10.3 Interferences
Table 10*1. Atomic Absorption Performance Data for
Determination of Fe3+
Fe'*
Optimum concentration range
Sensitivity
Detection Limit
0.3-5 mg/L
0.12 mg/L
0.03 mg/L
Chemical and spectral interferences can
contribute to inaccuracies in analyses of the
extracts by AA, ICP, or flame photometry. ICP
and flame photometric analysis are subject to
physical interferences as well. Interferences
are discussed further in Section 8.3.
10.4 Safety
The calibration standards, sample types,
and most reagents pose little hazard to the
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analyst. Wear protective clothing (laboratory
coat and gloves) and safety glasses when
preparing reagents, especially when concen-
trated acids and bases are used. The use of
concentrated acids and hydroxide solutions
should be restricted to a hood.
10.5 Apparatus
10.5.1 General
• Mechanical extractor, 24 place, manu-
factured by Centurion, Inc. (see Figure
7-1).
• Syringes, disposable, 60 mL, poly-
propylene; one sample tube and ex-
traction syringe for each sample.
• Rubber tubing, 1/8 by 1/4 inch; for
connecting syringe barrels.
• Bottles, polyethylene (LPE), with cap:
25 mL for mineral soil; 50 mL for
organic soil.
• Tubes, glass, 25 mL, centrifuge or
culture, with caps.
• Reciprocating shaker.
• Balance, analytical, capable of weigh-
ing to ±1 mg.
• Volumetric pipets, volumes as needed.
• Volumetric flasks, volumes as needed.
10.5.2 Instrumentation for
Determination by AA
• Atomic absorption spectrophotometer,
single- or dual-channel, single- or
double-beam, with grating monochro-
mator, photomultiplier detector,
adjustable slits, wavelength range of
190 to 800 nm, provisions for interfac-
ing with a strip chart recorder.
• Burner, as recommended by the in-
strument manufacturer; for certain
elements, nitrous oxide burner
required.
• Hollow cathode lamps, single element
lamps preferred, but multi element
lamps acceptable; electrodeless dis-
charge lamps may be used.
• Strip chart recorder.
10.5.3 Instrumentation for
Determination by ICP
• Inductively coupled plasma atomic
emission spectrometer, computer
controlled, with background correction
capability.
10.5.4 Instrumentation for
Determination by Flame
Photometry
• Flame photometer, either direct-
reading or internal-standard type; or
atomic absorption spectrometer in
flame emission mode.
10.6 Reagents and Consumable
Materials
• Stock calcium chloride solution (1.0 M
CaCy~Dissolve 55.493 g anhydrous
CaCI2 in DDI water and dilute to 500
mL. Two sources of high purity grade
CaCI2 are (1) SPEX Industries, Inc.,
Box 798, Metuchen, New Jersey
08840; telephone (201) 549-7144; and
(2) Aesar Johnson Matthey, Inc., Ea-
gles Landing, P.O. Box 1087,
Seabrook, New Hampshire 03874,
telephone (800) 343-1900.
• Calcium chloride (CaCy 0.002 M~
Dilute 4 mL 1.0 M CaCI2 to 2.000 L
with DDI water. If the pH of this
solution is not between 5 and 6.5,
adjust the pH by addition of dilute HCI
(see Section 6.6) or saturated
Ca(OH)2 (see Section 6.6).
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• Analytical filter pulp, Schleicher and
Schuell, No. 289, washed according to
the procedure given in Section 2.4.
• Calibration standards (Refer to Sec-
tion 8.6 for Ca2+, Mg2+, K+, Na+; Sec-
tion 10.10.4 for AI3+ and Fe3+.)
10.7 Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation
laboratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the analytical laboratory, all samples are
kept sealed and are refrigerated at 4 °C when
not in use.
For the determination of trace elements,
contamination and loss are of prime concern.
Dust in the laboratory environment, impurities
in reagents, and impurities on laboratory
apparatus which the sample contacts are all
sources of potential contamination. Sample
containers can introduce either positive or
negative errors in the measurement of trace
elements by (a) contributing contaminants
through leaching or surface desorption and (b)
by depleting concentrations through adsorp-
tion. Thus the collection and treatment of the
sample prior to analysis requires particular
attention.
10.8 Calibration and
Standardization
Within each class of instruments (AA,
ICP, and flame photometer), the calibration
procedure varies slightly.
Calibrate by analyzing a calibration blank
and a series of at least three standards within
the linear range. If an ICP is used, a multi-
element standard may be prepared and ana-
lyzed. For AA and flame photometric determi-
nations, the instrument must be calibrated by
single-element standards for each analyte.
The concentration of standards should
bracket the expected sample concentration;
however, the linear range of the instrument
should not be exceeded. An alternative, less
sensitive line may be used, but the standards
must bracket the samples.
Method of Standard Additions-VWnen
indicated by the matrix spike analysis, the ana-
lytes must be quantified by the method of
standard additions. In this method, equal
volumes of sample are added to a deionized
water blank and to three standards that con-
tain different known amounts of the analyte.
The volume of the blank and of each standard
must be the same. The absorbance or emis-
sion of each solution is determined and is then
plotted on the vertical axis of a graph, with
the concentrations of the known standards
plotted on the horizontal axis. When the
resulting line is extrapolated to zero absor-
bance, or emission, the point of intersection
of the abscissa is the concentration of the
unknown. The abscissa on the left side of the
ordinate is scaled the same as on the right
side, but in the opposite direction from the
ordinate. An example of a plot so obtained is
shown in Figure 8-1. The method of standard
additions can be very useful; however, for the
results to be valid the following limitations
must be taken into consideration:
• The absorbance or emission plot of
sample and standards must be linear
over the concentration range of con-
cern. For best results, the slope of
the plot should be nearly the same as
the slope of the aqueous standard
curve. If the slope is significantly
different (more than 20 percent),
caution should be exercised.
• The effect of the interference should
not vary as the ratio of analyte con-
centration of sample matrix changes,
and the standard addition should
respond in a similar manner as the
analyte.
• The determination must be free of
spectral interference and must be
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corrected for nonspecific background
interference.
10.9 Quality Control
The Ca2+ concentration of the extracting
solution must be within 5 percent of 80 ppm.
In addition to the QC inherent in the calibra-
tion procedures, the QC procedures described
in Section 2.6 must be followed. These in-
clude detection limit QC samples, QCCS, dupli-
cates, and matrix spikes.
10.10 Procedure
10.10.1 Preparation of Sample
Tubes
Prepare sample tubes by tightly com-
pressing 1 g of filter pulp into the bottom of a
syringe barrel with a modified plunger. (Modi-
fy the plunger by removing the rubber portion
and cutting off the plastic protrusion.) Wash
the filter pulp with DDI water before use.
10.10.2 Sample Preparation
For mineral soils, weigh air-dried sample,
equivalent to 10.00 g oven-dried soil, into sam-
ple tube. Place sample tube in upper disc of
extractor and connect to inverted extraction
syringe, the plunger of which is inserted in the
slot of the stationary disc of the extractor.
Add 20 mL 0.002 M CaCI2 and stir with
glass stirring rod for 15 seconds. Leave stir-
ring rod in syringe.
Let the sample mixture stand for 30
minutes and stir again for 15 seconds. Let
the sample mixture stand for another 30 min-
utes, then continue at Section 10.10.3. This is
a 1:2 extraction.
For organic soils, weigh air-dried sample,
equivalent to 4.00 g oven-dried soil, into a
small glass tube. Add 30 mL 0.002 M CaCI2,
cap, and shake for 1 hour.
Place a sample tube in the upper disc of
the extractor and connect to inverted extrac-
tion syringe, the plunger of which is inserted in
the slot of the stationary disc of the extractor.
Then quantitatively transfer the sample
and 0.002 M CaCI2 solution to a sample tube.
Rinse shaking tube with 10 mL 0.002 M CaCI2
into the sample tube. The total volume of
0.002 M CaCI2 should equal 40 mL This is a
1:10 extraction.
For extremely absorbent organic soils,
use a 1.60 g sample and the same volumes of
solution. This is a 1:25 extraction.
10.10.3 Extraction
Turn on extractor. Extract at the 17-hour
rate (or overnight) until most of the available
CaCI2 solution is recovered.
Turn off extractor and pull plungers down
as far as extractor will allow. Disconnect sy-
ringes from sample tube. Transfer extract to
polyethylene containers.
If dilution is necessary, take an aliquot
of known volume and dilute in a volumetric
flask. Take this dilution factor into account
when calculating the analyte concentrations.
10.10.4 Determination of Ca2+, K+
and Ar
Analyze extract for Ca2+, Mg2+, Na+, and
Fe3+ by flame AA or ICP. K+ must be deter-
mined by AA or flame photometry because ICP
is not sufficiently sensitive in the determination
of K+ to quantify concentrations less than 100
mg/L Ar* must be determined by ICP be-
cause flame AA is not sufficiently sensitive in
the determination of AI3+ to quantify concentra-
tions less than 0.1 mg/L.
The procedures given in Section 8.10 are
used for these determinations. However, the
standard solutions are prepared with 0.002 M
CaCI2 rather than with 1.0 N NH4CI or NH4OAc.
For aluminum and iron determinations, the
additional procedural detail given in sections
10.10.4.1 and 10.10.4.2 is required.
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10.10.4.1 Determination of
Aluminum--
10.10.4.1.1 Preparation of Aluminum Standard
Solutions-
• Primary aluminum standard (1,000
mg/L AI)-Carefully weigh 1.000 g
aluminum powder (spectroscopic
grade). Add 15 ml_ concentrated HCI
and
5 mL concentrated HNO3 to the
metal, cover the beaker, and warm
gently. When metal is completely
dissolved, transfer solution quanti-
tatively to a 1-L volumetric flask and
dilute to volume with DDI water.
Alternatively, a commercially available,
certified Al standard may be used.
• Nitric acid (HNCg,
Ultrapure grade.
concentrated-
• Nitric acid (0.5 percent v/v HNO^-Add
1 mL concentrated HNO3 (Ultrapure
grade) to DDI water and dilute to 200
mL
• Calibration standards-Prepare cali-
bration standards at the time of
analysis. The calibration standards
should be prepared in 0.5 percent (v/v)
HNO3. To each 100 mL of standard
and sample alike, add 2.0 mL potassi-
um chloride solution.
10.10.4.1.2 Suggested Instrument Conditions
(Genera/J~Wave\er\Qlb 308.215 nm.
10.10.4.1.3 Analytical Procedure--
1. Calibrate the instrument as directed
by the instrument manufacturer.
2. Analyze the samples.
3. If a sample concentration exceeds the
linear range, dilute with acidic media
and reanalyze.
4. Record results as milligrams AI3+ per
liter (mg AI34/L).
10.10.4.1.4 Precision and Accuracy-Refer to
Table 10-3 for these data.
10.10.4.2 Determination of Iron--
10.10.4.2.1 Preparation of Iron Standard
Solutions-
• Primary iron standard (1,000 mg/L Fe)
-Carefully weigh 1.000 g pure iron
powder (spectroscopic grade). Dis-
solve in 5 mL concentrated HNO3 and
warm if necessary. When iron is
completely dissolved, dilute solution to
1.00 L with DDI water.
• Calibration standards-At the time of
analysis, prepare calibration stan-
dards in the correct matrix spanning
the desired concentration range.
10.10.4.2.2 Suggested Instrumental Conditions
(General)~\ron hollow cathode lamp; wave-
length, 248.3 nm; fuel, acetylene; oxidant, air;
type of flame, oxidizing.
10.10.4.2.3 Analytical Procedure--
1. Calibrate the instrument.
2. Analyze the samples.
3. Dilute and reanalyze any samples for
which the concentration exceeds the
calibrated range.
4. Record results in milligrams Fe3+ per
liter (mg Fe3+/L).
and 10.11.)
(See sections 8.11
10.10.4.2.4 Afotes-The following lines may also
be used: 248.8 nm, relative sensitivity 2; 271.9
nm, relative sensitivity 4; 302.1 nm, relative
sensitivity 5; 252.7 nm, relative sensitivity 6;
372.0 nm, relative sensitivity 10.
10.10.4.2.5 Precision and Accuracy--^ inter-
laboratory study on trace metal analyses by
atomic absorption was conducted by the
Quality Assurance and Laboratory Evaluation
Branch of EMSL-Cincinnati. Six synthetic
concentrates containing varying levels of
-------
Table 10-3.
Element
Al
Fe
Inductively
True
Value
(W9/U
700
600
Coupled Plasma Precision
Sample 1
Mean
Reported
Value
(WS/U
696
594
Mean
%RSD
5.6
3.0
and Accuracy data
True
Value
(tfd/U
60
20
Samole 2
Mean
Reported
Value
(ua/U
62
19
(U.S. EPA,
Mean
%RSD
33
15
1983)
True
Value
(ua/L)
160
180
Section 10
Revision 2
Date: 12/86
Page 6 of 7
Sample 3
Mean
Reported
Value Mean
(ua/U %RSD
161 13
178 6.0
Note: Not all elements were analyzed by all laboratories.
aluminum, cadmium, chromium, copper, iron,
manganese, lead, and zinc were added to
natural water samples. The statistical results
for iron were as follows:
Number
of Labs
82
85
78
79
57
54
True Values Mean Value Deviation Accuracy
ua/liter ua/liter ua/liter as % Bias
840
700
350
438
24
10
855
680
348
435
58
48
173
178
131
183
69
69
1.8
-2.8
-0.5
-0.7
141
382
10.11 Calculations
1. Instruments may be calibrated to
output sample results directly in con-
centration units, i.e., mg/L If the
instrument is not so calibrated or pro-
grammed, then either (1) the slope of
the linear calibration curve is calcu-
lated, and sample concentrations are
subsequently calculated, or (2) a
manual calibration curve is prepared,
and sample concentrations are deter-
mined by comparing the sample signal
to the calibration curve.
2. If dilutions are performed, the appro-
priate factor must be applied to
sample values.
3. Report Ca2+, Mg2+, K+, Na+, AI3+, and
Fe3* in units of meq/100 g oven-dried
soil to the nearest 0.001 meq/100 g.
To convert concentration of analyte in
the extract to analyte in oven-dried
soil, use equations 8-1 through 8-3
(see Section 8.11.4).
NOTE: Report Ca2+ without adjusting for the
Ca2+ levels in the CaCI2 extracting solution, i.e.,
do not subtract the blank.
meq /mg
100 g soil I L
/meq \ /mL extract
mmol
Atomic wt. (mg) J
mmol A g soil
where:
Cation
Ca"
Mg"
K*
Na*
Al"
Fe"
and
Soil Tree
mineral
organic
highly
absorbent
organic
— IV ' wj
Atomic wt.
40.080
24.305
39.098
22.990
26.982
55.847
grams Soil
10.00
4.00
1.60
(10-1)
meq/mmol
2
2
1
1
3
3
mL extract
20
40
40
ratio
1:2
1:10
1:25
10.12 Precision and Accuracy
Precision and accuracy for AA determi-
nations are provided in the analyte-specific
section (8.10.1.1.6 Ca2+, 8.10.1.2.6 Mg2+,
8.10.1.3.5 K+, 8.10.1.4.5 Na+, and 10.10.4.2.5
Fe3+). Precision and accuracy for ICP determi-
nations are given in part in Section 8.12.2;
additional data are presented below:
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Section 10
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Page 7 of 7
In an EPA Round Robin Phase I study,
seven laboratories applied the ICP technique
to acid-distilled water matrices that had been
dosed with various metal concentrates. Table
10-3 lists the results of this study.
Patel et al. (1984) report spike recovery
percentages in seven wastes that average
102.3 percent for aluminum and 93.1 percent
for iron.
Again, because of differences in matrices
and in sample processing, neither of the above
studies necessarily represents precision and
accuracy for soil analyses, but simply indicates
likely trends.
10.13 References
Blume, L J., M. L Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey, U.S. Envi-
ronmental Protection Agency, Las Vegas,
Nevada. Appendix A In: Direct/Delayed
Response Project Southern Blue Ridge
Province Field Sampling Report. Vol. I:
Field Sampling.
Protection Agency.
U.S. Environmental
Fassel, V. A. 1982. Analytical Spectroscopy
with Inductively Coupled Plasmas -
Present Status and Future Prospects.
In: Recent Advances in Analytical Spec-
troscopy. Pergamon Press, New York,
New York.
Patel, B. R., G. A. Raab, D. Cardenas, and T.
W. Riedy. 1984. Report on a Single-
Laboratory Evaluation of Inductively
Coupled Plasma Optical Emission Meth-
od 6010. U.S. Environmental Protection
Agency, Las Vegas, Nevada.
U.S. Environmental Protection Agency. 1983
(revised). Methods for Chemical Analysis
of Water and Wastes. Method 200.0,
Atomic Absorption Methods, and Method
200.7, Inductively Coupled Plasma Atomic
Emission Spectrometric Method for the
Trace Element Analysis of Water and
Wastes. EPA/600/4-79-020. U.S. Environ-
mental Protection Agency, Cincinnati,
Ohio.
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Section 11
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Page 1 of 7
// Extractable Iron and Aluminum
11.1 Scope and Application
Iron and aluminum are extracted from
soil into sodium pyrophosphate, citrate-dithio-
nite, and acid-oxalate solutions. According to
the Johnson and Todd (1983) iron and alumi-
num speciatton scheme, the pyrophosphate
extract contains organically bound iron (Fe-p)
and aluminum (Al-p), the citrate-dithionite
extract contains nonsilicate Fe (Fe-c) and Al
(Al-c), and the acid-oxalate extract contains
organic and amorphous oxides of Fe (Fe-o)
and Al (Al-o).
In general, Al in these extracts does not
indicate the readily available species that are
known to cause fish kills. The exchangeable
Al3* from the unbuffered KCI extract (see
Exchangeable Acidity, Section 9) is more
indicative of readily available Al at field pH
conditions. The Fe and Al values from the
pyrophosphate, acid-oxalate, and citrate-
dithionite extracts relate well to the sulfate
adsorption capacity and have been used as an
indication of this property (Fernandez, 1983).
Detection limits and related information
for determination of Fe and Al in the extracts
are provided in Table 10-2 and Table 11-1.
Table 11-1. Atomic Absorption Performance Data for
Determination of Fe34 and AJ3+
Fe'
Al"
Optimum
concentration
range
Sensitivity
Detection Limit
0.3-5 rng/L
0.12 mg/L
0.03 mg/L
5-50 mg/L at 309.3 nm
1 mg/L
0.1 mg/L
11.2 Summary of Method
Each of three portions of a soil sample
is treated with a different solution to extract
iron and aluminum. The three extracting
solutions are 0.1 M sodium pyrophosphate, a
sodium citrate-sodium dithionite solution, and
an oxalic acid-ammonium oxalate solution.
After the extraction procedure, the three solu-
tions are analyzed for iron and aluminum by
atomic absorption spectrometry (AA) or by
inductively coupled plasma atomic emission
spectrometry (ICP). These instrumental tech-
niques are summarized in Section 8.2. The
method is modified from USDA/SCS (1984).
11.3 Interferences
Chemical and spectral interferences can
contribute to inaccuracies in analysis of the
extracts by AA or ICP. Analysis by ICP is
subject to physical interferences as well.
Interferences are discussed more completely
in Section 8.3.
11.4 Safety
The calibration standards, sample types,
and most reagents pose no hazard to the
analyst. Wear protective clothing (laboratory
coat and gloves) and safety glasses when
preparing reagents, especially when concen-
trated acids and bases are used. The use of
concentrated acids and hydroxide solutions
should be restricted to a hood.
Follow the safety precautions provided
by the manufacturer when operating instru-
ments.
Follow good laboratory practices
when handling compressed gases. Cylinders
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Page 2 of 7
should be chained or bolted in an upright
position.
11.5 Apparatus and Equipment
11.5.1 General
• Centrifuge bottles, 250 ml, polypro-
pylene.
• Bottles, polyethylene (LPE), 25 mL
• Reciprocating shaker.
• Centrifuge.
• pH meter and pH electrode.
• Mechanical extractor, 24 place, manu-
factured by Centurion, Inc. (Figure
7-1).
• Syringes, 60 mL, polypropylene, one
sample tube, one reservoir tube, and
one tared extraction syringe for each
sample.
• Repipet or equivalent.
• Fleakers, or equivalent glassware.
• Volumetric pipets, volumes as needed.
• Volumetric flasks, volumes as needed.
11.5.2 Instrumentation for
Determination by AA
• Atomic absorption spectrophotometer,
single- or dual-channel, single- or
double-beam, with grating monochro-
mator, photomultiplier detector,
adjustable slits, wavelength range of
190 to 800 nm, provisions for interfac-
ing with a strip chart recorder.
• Burner as recommended by the instru-
ment manufacturer; for certain ele-
ments, nitrous oxide burner required.
• Hollow cathode lamps, single element
lamps preferred, but multielement
lamps acceptable; electrodeless dis-
charge lamps may be used.
• Strip chart recorder.
11.5.3 Instrumentation for
Determination by ICP
• Inductively coupled plasma atomic
emission spectrometer, computer-con-
trolled, with background correction
capability.
11.6 Reagents and Consumable
Materials
11.6.1 Sodium Pyrophosphate
Extraction
• NBS-traceable pH buffers of pH = 7
and pH = 10.
• Sodium pyrophosphate (Na4P2O7*
10H2O), 0.1 M-Dissolve 44.61 g
Na4P2O7«10 H2O in DDI water. Dilute
to 1.0 L Adjust to pH 10.0 by drop-
wise additions of 1 N NaOH or 1 N
H3P04.
• Sodium hydroxide (NaOH), 1 N-Dis-
solve 10 g NaOH in DDI water. Dilute
to 250 mL Store in polyethlene
container.
• Phosphoric acid (H3POJ, concentrated.
• Superf loc 16, 0.2 percent solution (v/v)
in DDI water (suggested source:
American Cyanamid Co., P.O. Box
32787, Charlotte, NC 28232; telephone:
800/438-5615).
11.6.2 Citrate-Dithionite Extraction
• Sodium dithionite (Na2S2OJ.
• Sodium citrate (Na3C8H8O7«5H2O).
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Page 3 of 7
• Citrate-dithionite reagent-Dissolve 160
g sodium dithionite and 2,000 g sodi-
um citrate into approximately 8 liters
of DDI water. (This may require pro-
longed magnetic stirring or additional
DDI water to totally dissolve the
salts.) Dilute to 10 L Store at 4 °C
and use the same day.
• Superfloc 16, 0.2 percent solution (v/v)
in DDI water.
11.6.3 Acid-Oxalate Extraction
• NBS-traceable pH buffers of pH = 4
and pH = 3 or pH = 2.
• Ammonium oxalate [(NHJ2C2O4»H2O].
• Oxalic acid (H2C2O4-H2O).
• Acid-oxalate reagent-Solution A:
Dissolve 284 g ammonium oxalate
[(NHJgCA'HaQ] in 10 L DDI water.
Solution B: Dissolve 252 g oxalic acid
(H2C2O4»H2O) in 10 L distilled water.
Mix four parts solution A with three
parts solution B. Adjust pH to 3.0 by
adding either solution A or B.
• Analytical filter pulp, Schleicher and
Schuell, No. 289.
11.6.4 Determination of Fe and Al
• Calibration standards-The matrix of
the calibration standards should
match the matrix of the soil extracts
as closely as possible in order to
assure maximum accuracy. Therefore,
the calibration standards should be
prepared with the extracting solution
rather than water as the diluent.
Refer to Section 11.10.4.1. for prepara-
tion of Al standard solutions and to
Section 10.10.4.2.1 for preparation of
Fe standard solutions.
11.7 Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labo-
ratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the laboratory, all samples are kept sealed
and are refrigerated at 4 °C when not being
used. The citrate-dithionite extractions should
be analyzed within 24 hours after preparation;
the pyrophosphate and acid-oxalate extracts,
within 48 hours after preparation.
11.8 Calibration and
Standardization
11.8.1 General
Within each class of instruments (AA
and ICP), the calibration procedure varies
slightly. Calibrate the instrument by analyzing
a calibration blank and a series of at least
three standards within the linear range. If an
ICP is used, a multielement standard may be
prepared and analyzed. For AA determina-
tions, the instrument must be calibrated for
each analyte. The concentration of standards
must bracket the expected sample concentra-
tion; however, the linear range of the instru-
ment should not be exceeded.
11.8.2 Method of Standard
Additions for Determination
of Fe and Al
When indicated by the matrix spike ana-
lysis, the analytes must be quantified by the
method of standard additions.
Note: It is difficult to maintain a stable, con-
centrated solution of AI3+ for performing
matrix spikes or standard additions.
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Section 11
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Page 4 of 7
In this method, equal volumes of sample
are added to a deionized water blank and to
three standards that contain different known
amounts of the test analyte. The volume of
the blank and of each standard must be the
same. The absorbance or emission of each
solution is determined and is then plotted on
the vertical axis of a graph, with the concen-
trations of the known standards plotted on the
horizontal axis. When the resulting line is
extrapolated to zero absorbance or emission,
the point of intersection of the abscissa is the
concentration of the unknown. The abscissa
on the left side of the ordinate is scaled the
same as on the right side but in the opposite
direction from the ordinate. An example of a
plot so obtained is shown in Figure 8-1. The
method of standard additions can be very
useful; however, for the results to be valid, the
following limitations must be taken into con-
sideration:
• The absorbance or emission plot of
sample and standards must be linear
over the concentration range of con-
cern. For best results, the slope of
the plot should be nearly the same as
the slope of the aqueous standard
curve. If the slope is significantly
different (more than 20 percent), cau-
tion should be exercised.
• The effect of the interference should
not vary as the ratio of analyte con-
centration of sample matrix changes,
and the standard addition should
respond in a similar manner as the
analyte.
• The determination must be free of
spectral interference and must be
corrected for nonspecific background
interference.
11.9 Quality Control
In addition to the QC inherent in the
calibration procedures, the QC procedures
described in Section 2.6 must be followed.
These include detection limit QC samples,
QCCS, duplicates, and matrix spikes.
11.10 Procedures
//. 10.1 Sodium Pyrophosphate
Extraction
1. Place 2.00 g of air-dried soil into a
250-mL centrifuge bottle. Add 200 mL
0.1 M Na4P2O7, cap, and shake over-
night (17 hours) on a reciprocating
shaker.
2. Remove centrifuge bottle from shaker.
Add 4 mL 0.2 percent Superfloc solu-
tion. Shake for 15 seconds and cen-
trifuge at 510 G for 10 minutes.
3. Remove centrifuge bottle from centri-
fuge. Examine the supernatant for
suspended clays. Because the pyro-
phosphate solution is relatively vis-
cous and the clays are Na-saturated,
the supernatant may not be clear. If
it is not, repeat step 2.
4. Decant and save the supernatant.
Store the supernatant at 4 °C. If dilu-
tion is necessary, take an aliquot of
known volume and dilute in a volumet-
ric flask. Take this dilution factor into
account in calculating the concentra-
tion of Fe3+ and AI3+.
5. Analyze for Fe3+ and AI3+ within 24
hours of the end of the extraction.
(Refer to Section 11.10.4 for determi-
nation of AI3+ and to Section 10.10.4.2
for determination of Fe3+.)
11.10.2 Citrate-Dithionite
Extraction
1. Weigh approximately 4.00 ± 0.01 g air-
dried soil into a 250-mL centrifuge
bottle. Add 125 mL of the citrate-
dithionite extraction solution, cap, and
shake overnight (17 hours) on a recip-
rocating shaker.
An alternative method: Add 2 g
Na2S2O4 and 20 to 25 g Na3C6H507-
5H2O. Add 125 mL DDI water, cap,
-------
Section 11
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Date: 12/86
Page 5 of 7
and shake overnight (17 hours) on a
reciprocating shaker.
2. Add 4 mL 0.2 percent Superf loc solu-
tion and shake vigorously for approxi-
mately 30 seconds. Centrifuge at 510
G for 10 minutes (higher speeds and
longer times may be required for soils
high in silts and clays).
3. Remove centrifuge bottle from centri-
fuge. Examine the supernatant for
suspended clays. If the supernatant
is not clear, repeat step 2.
4. Decant and save the supernatant for
Fe3+ and AI3+ analysis. Store the
supernatant at 4 °C. If dilution is
necessary, take an aliquot of known
volume and dilute in a volumetric
flask. Take this dilution factor into
account in calculating the concentra-
tion of Fe3+ and AI3+.
5. Analyze for Fe3+ and AI3+ within 24
hours of the end of the extraction.
(Refer to Section 11.10.4 for determi-
nation of AI3+ and to Section 10.10.4.2
for determination of Fe3+.)
//. 10.3 Acid-Oxalate Extraction
This extraction is sensitive to light and,
therefore, should be performed under condi-
tions of darkness. To minimize variability
associated with different technicians, this
procedure requires the use of a mechanical
extractor.
1. For minerals soils, prepare sample
extraction tubes by forcing a 1-g ball
of filter pulp into the bottom of sy-
ringe barrel with syringe plunger.
Weigh about 0.5 ± 0.001 g soil into
tube.
Place sample tube in extractor, attach
extraction syringe, and add 15 mL
acid-oxalate reagent from a repipet or
equivalent unit, washing down sides
of tubes. Attach reservoir tube and
allow moistened sample to stand for
1 hour. Continue at step 3.
2. For organic soils, weigh about 0.5 ±
0.001 g soil into a small glass tube.
Add 10 mL acid-oxalate reagent and
shake for 1 hour on a reciprocating
shaker.
Prepare sample extraction tubes by
forcing a 1-g ball of filter pulp into
bottom of syringe barrel with syringe
plunger. Place sample tube in extrac-
tor and attach extraction syringe.
Quantitatively transfer soil to sample
tube with 5 mL acid-oxalate reagent
so that the total volume added to the
soil equals 15 mL Attach reservoir
tube. Continue at step 3.
3. For mechanical extraction, extract at
a setting of 1 hour until 0.5 to 1.0 cm
of extracting solution remains above
sample. Turn off extractor.
Add 35 mL acid-oxalate reagent to the
reservoir from a repipet or equivalent
unit. Place a black plastic bag over
the extractor to protect samples from
light and other contamination. Extract
overnight at a setting of 17 hours.
NOTE: Although the reagents are not sensi-
tive to light, the combination of soil
and acid-oxalate reagent is reactive to
light. In the presence of light, the
Fe3+ and AI3+ extracted are not limited
to the organic and amorphous oxide
species.
4. Remove syringe. Store the extract at
4 °C. If dilution is necessary, take
an aliquot of known volume and dilute
in a volumetric flask. Take this dilu-
tion factor into account in calculating
the concentrations of Fe3+ and AI3+.
5. Analyze for Fe3+ and AI3+ within
48 hours of the end of the extrac-
tion. (Refer to Section 11.10.4 for
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Section 11
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Page 6 of 7
determination of AI3+ and Section
10.10.4.2 for determination of Fe3+.)
The procedures given in Section 8.10
are used for these determinations.
However, the standard solutions are
prepared with 0.002 M CaCI2 rather
than with 1.0 N NH4CI or NH4OAc.
For aluminum and iron determinations
by AA, the additional procedural
detail given in sections 10.10.4.1 and
10.10.4.2 is required. Samples should
be analyzed within the holding times
specified in Section 11.7.
//. 10.4 Determination of
Aluminum
11.10.4.1 Preparation of Aluminum
Standard Solutions--
• Primary aluminum standard (1,000
mg/L AI)-Carefully weigh 1.000 g alu-
minum powder (spectroscopic grade).
Add 15 ml_ concentrated HCI and 5
ml_ concentrated HNO3 to the metal,
cover the beaker, and warm gently.
When metal is completely dissolved,
transfer solution quantitatively to a 1-
L volumetric flask and dilute to vol-
ume with DDI water. Alternatively, a
commercially available, certified Al
standard may be used.
• Nitric acid (HNOJ,
Ultrapure grade.
concentrated-
• Nitric acid (0.5 percent v/v HNOj)-
Add 1 mL concentrated HN03 (Ultra-
pure grade) to DDI water and dilute
to 200 mL
• Potassium chloride solution, ionization
suppressant-Dissolve 95 g potassium
chloride (KCI) in DDI water and dilute
to 1.00 liter.
• Calibration standards-Prepare cali-
bration standards at the time of anal-
ysis. The calibration standards
should be prepared in 0.5 percent (v/v)
HNO3. To each 100 mL of standard
and sample alike, add 2.0 mL potassi-
um chloride solution.
11.10.4.2 Suggested Instrument
Conditions (General)--
Aluminum hollow cathode lamp; wave-
length 309.3 nm; fuel, acetylene; oxidant, ni-
trous oxide.
11.10.4.3 Analytical Procedure-
1. Calibrate the instrument as directed
by the instrument manufacturer.
2. Analyze the samples.
3. If a sample concentration exceeds the
linear range, dilute with acidic media
and reanalyze.
4. Record results as milligrams Al3* per
liter (mg AI3+/L).
11.10.4.4 Notes-
The following lines may also be used:
308.2 nm, relative sensitivity 1; 396.2 nm, rela-
tive sensitivity 2; 394.4 nm, relative sensitivity
2.5.
11.10.4.5 Precision and Accuracy-
An interlaboratory study of trace metal
analyses by atomic absorption was conducted
by the Quality Assurance and Laboratory Eval-
uation Branch of EMSL-Cincinnati. Six synthet-
ic concentrates that contained varying levels
of aluminum, cadmium, chromium, copper,
iron, manganese, lead, and zinc were added to
natural water samples. The statistical results
for aluminum were as follows:
Number True Values Mean Value Deviation Accuracy
of Labs us/liter ua/liter tig/liter as % Bias
38
38
37
37
22
21
1,205
1,004
500
625
35
15
1.281
1,003
463
582
96
109
299
391
202
272
108
168
6.3
-0.1
-7.4
-6.8
175
626
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Section 11
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Page 7 of 7
11.11 Calculations
Report percentage to 0.001 percent.
%AI = (mg AI7L) I
/ V
[dilution factor
I as needed /
%Fe = (mg Fe/Ljl
(dilution factor \
I as needed I
U(mL extract)
I oven-dried soil
(11-1)
(mL extract)
I oven-dried soil
(11-2)
where,
mL extract
204 for pyrophosphate extract
129 for citrate-dithionite extract
50 for acid-oxalate extract
11.12 Precision and Accuracy
Precision and accuracy information may
be found in the following locations: for alumi-
num determinations by AA, Section 11.10.4.5;
for iron determinations by AA, Section
10.10.4.2.5; for iron and aluminum determina-
tions by ICP, Section 10.12.
11.13 References
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey, U.S. Envi-
ronmental Protection Agency, Las Vegas,
Nevada. Appendix A In: Direct/Delayed
Response Project Southern Blue Ridge
Province Field Sampling Report. Vol. I:
Field Sampling. U.S. Environmental
Protection Agency.
Fernandez, I. 1983. Field Study Program
Elements to Assess the Sensitivity of
Soils to Acidic Deposition Induced Alter-
ations in Forest Productivity. Technical
Bulletin No. 404. National Council of the
Paper Industry for Air and Stream Im-
provement, Inc., New York, New York.
Johnson, D. W., and D. E. Todd. 1983. Some
Relationships among Fe, Al, C, and SO4
in a Variety of Forest Soils. Soil Sci.
Soc. Am. J., Vol. 47, pp. 702-800.
U.S. Department of Agriculture/Soil Conserva-
tion Service. 1984. Soil Survey Laborato-
ry Methods and Procedures for Collecting
Soil Samples. Soil Survey Investigations
Report No. 1, USD A. U.S. Government
Printing Office, Washington, D.C.
Blume, L J., M. L Papp, K. A. Cappo, J. K.
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Section 12
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Page 1 of 8
12 Extractable Sulfate and Nitrate
12.1 Scope and Application
Sulfur in the form of sulfate (SO42") is
considered a major controlling factor in soil
acidity. It is necessary, therefore, to deter-
mine both the quantity of sulfate held in the
soil and how much of this sulfate is readily
available to the soil solution. Sulfate on anion
exchange sites, or loosely associated with
cations, is readily removed. When strongly
adsorbed to the soil surface or complexed with
nonsoluble organic material, sulfate is not
easily dislocated.
Nitrogen in the form of nitrate (NOg) also
may be influential in the acidification of soil.
It is the thought that nitrate accumulates
beneath the snow pack as a result of biologi-
cal activity at the snow-soil interface. Then a
relatively concentrated flush of nitrate moves
through the soil profile after spring thaw.
Therefore, samples collected in the spring,
prior to heavy rains and before uptake of the
nitrate by vegetation, should contain more
nitrate than samples collected during the fall.
Also, nitrogen may be a component of both
dry and wet deposition.
Two extractions have been developed to
determine the levels of sulfate and nitrate in
the soil. The first extraction, for nitrate and
readily available sulfate, utilizes DDI water.
The water extraction will include the sulfate
and nitrate on anion exchange sites and asso-
ciated with cations. The phosphate (PO^)
extraction will include the adsorbed and some
complexed sulfate. In general, the trivalent
charge on the phosphate ion enables phos-
phate to displace divalent sulfate from adsorb-
ing and complexing sites. This, combined with
mass action, will extract nearly all sulfate from
the soil.
From the sulfate adsorption isotherm, an
estimate of the inorganic sulfate retention
capacity of the soil can be determined. The
PO*3" extractable sulfate can be Used to ap-
proximate the total amount of adsorbed sul-
fate. Because drying the soil prior to analysis
allows oxidation of reduced forms of sulfur,
the water extractable sulfate approximates
both oxidized and reduced forms of sulfur
which will readily enter the soil solution.
12.2 Summary of Method
Two portions of a soil sample are ex-
tracted. DDI water is the extracting matrix for
nitrate and readily available sulfate. The
extracting matrix for sulfate that is more
difficult to dislocate is 0.016 M sodium phos-
phate (containing 500 mg P/L). After the
extractions are completed, the analytes are
determined by ion chromatography. This
method is modified from Fernandez (1983) and
Tabatabai (1982).
12.3 Interferences
An interference can occur during the ion
chromatographic analysis of the 0.016 M
NaH2PO4 (1500 mg PO^/L) extract. At such a
high concentration, the phosphate peak over-
laps the SO/1" peak under typical 1C conditions
(usually phosphate elutes prior to sulfate). By
using the mixed eluent 0.0020 M Na2C(V0.0020
M NaOH (an eluent whose pH is greater than
the pK of HPO42 [pK = 12.37] and which is
sufficiently buffered to maintain the pH in the
presence of the eluting phosphate), phosphate
elutes after SO^, and the interference is mini-
mized or eliminated. Elution time for sulfate is
increased by several minutes with this modifi-
cation.
Soil extracts can rapidly degrade a
column; therefore, frequent cleaning with dilute
acid is recommended (after each 50 samples).
Also, the use of guard columns is recommen-
ded. A guard column for organics should be
used when analyzing PO43' extracts.
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Section 12
Revision 2
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Page 2 of 8
12.4 Safety
Follow standard laboratory safety prac-
tices and wear gloves, safety glasses, and a
laboratory coat when preparing and handling
reagents. Follow the safety precautions of the
manufacturer when operating the instruments.
12.5 Apparatus and Equipment
• Centrifuge tubes, with screw caps, 50
mL
• Centrifuge.
• Filtration apparatus.
• Membrane filters, 0.20 pm pore.
• Reciprocating shaker.
• Vortex mixer (optional).
• Ion chromatograph, Dionex models 10,
12, 14,16, or 2000 series or equivalent
with ASS, AS4a, or equivalent anion
separator column, anion fiber or
micromembrane suppressor column or
equivalent; appropriate guard column
recommended to preserve the sepa-
rator column.
• Automated injection system, com-
mercially available from several
manufacturers.
• Data recording system, integrator or
strip chart recorder for recording ion
chromatographs; the nominal output
to recorder is 1.0 V. The Dionex plane
parallel electrode conductivity detector
or equivalent unit gives a linear re-
sponse with concentration until elec-
tronic saturation occurs at approxi-
mately 4.0 V. Therefore, several ana-
lytical ranges on recorders set at
different full-scale voltages can be
monitored simultaneously.
• Volumetric pipets, volumes as needed.
• Volumetric flasks, volumes as needed.
12.6 Reagents and Consumable
Materials
Unless stated otherwise, all chemicals
must be ACS reagent grade or better. The
concentrated and working eluents, as well as
the regenerant used, are based on the recom-
mendation of the manufacturer for the parti-
cular column and instrument used. These may
be altered to increase resolution or decrease
separation time. The eluents, suppressors,
and regenerants are acceptable for a Dionex
unit with an AS series anion separator column.
These will change with the manufacturer and
column used. Even individual columns may
require variation. All modifications must be
documented before routine analysis begins.
• Parafilm.
• Monobasic sodium phosphate (NaH2P
O4«H2O) 0.016 M (500 mg P/L)-Dis-
solve 2.227 g NaH2PO/H2O in DDI
water and dilute to 1.000 L
• Sodium carbonate
• Concentrated eluent, 0.40 M Na2CO3-
Dissolve 42.396 g Na2CO3 in DDI
water and dilute to 1.000 L Seal and
store until use.
• Sodium hydroxide (NaOH), pellets or
flakes.
• Sodium hydroxide (50 percent wt/v)~
Dissolve 50 g NaOH in DDI water and
dilute to 100 mL This dissolution
generates heat; therefore, a water- or
ice-bath should be used to cool the
dissolution vessel.
• Working eluent, 0.0020 M Na-jCOg/
0.0020 M NaOH - Dilute 20.0 mL con-
centrated eluent to 4.00 L and adjust
pH to 12.5 with 50 percent NaOH.
Other working eluents for the LECO
type columns include: (1) 0.003 M
Na2CO3 for water extractable sulfate
and 0.002 M NaHCO3/0.0025 M NaOH
for phosphate extractable sulfate, and
(2) 0.003 M NaHCO3/0.0024 M Na2CO3
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Section 12
Revision 2
Date: 12/86
Page 3 of 8
for both sulfates. The eluent used
must give clean separation of the
peaks without excessive band broad-
ening.
• Sulfuric acid (H2SOJ, concentrated.
• Fiber suppressor regenerant-For
water-extractable samples, H2SO4 (25
mM) - Dilute 10 mL of 2.5 M HjSCv to
1.0 L with DDI water.
• Magnesium sulfate (MgSOJ.
• Sodium nitrate (NaNOJ.
• Stock resolution standard (1,000 mg
SO^/L, 1,000 mg PO4*VI_ 1,000 mg
NO3VL)--Dissolve 1.2530 g MgSO4,
1.3708 g NaNO3,3.5397 g NaH2PO4«12-
H20 in DDI water and dilute to 1.00 L
Table 12-1. Example of Concentration of Calibration
Standard* Used for the Analysis of Water
Sample* by Ion Chromatography
Working resolution standard (10.0 mg
NOjT/L, 10.0 mg SO42"/L, and 10.0 mg
PO4 /L)-Dilute 10.00 mL of stock reso-
lution standard to 1.00 L with DDI
water.
• Primary mixed standard (1,000 mg
SO^/L and 1,000 mg NO3YL)--Dissolve
1.2530 g MgSO4 and 1.3708 g NaNO3
in DDI water and dilute to 1.00 L
• Secondary standards:
Solution A-Dilute 10.00 mL of primary
mixed standard solution to 100.00 mL
with DDI water (100.0 mg SO^/L and
100.0 mg N037L).
Standard Solution B~Dilute 5.00 mL
primary mixed standard solution to
500.00 mL with DDI water (10.0 mg
SO4*/L and 10.0 mg NO37L).
• Calibration standards-Use secondary
standard solutions A and B to pre-
pare the calibration standards (see
Table 12-1). Calibration standards are
prepared by diluting a volume of stan-
dard solution A or B with DDI water.
Concentration
in ma/L
SO.1- NO/
50 50
20 20
10 10
2 2
0.5 0.5
Milliliters of Standard
Solution per 100 mL
of Calibration Standard
5.00 of primary (1,000 mg/L)
20.00 of A
100.0 of B
2.00 of A
5.00 of B
12.7
Calibration standards must be pre-
pared daily. Calibration standards of
concentrations other than those
shown in Table 12-1 may be used as
long as standard concentrations
bracket the sample concentrations.
Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labo-
ratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the laboratory, all samples are kept sealed
and are refrigerated at 4 °C when not in use.
12.8 Calibration and
Standardization
Calibrate ion chromatograph as recom-
mended by the manufacturer. Use the calibra-
tion standards in Table 12-1, and any addition-
al standards needed, to bracket the sample
concentrations. Nonlinear response can result
when the separator column capacity is ex-
ceeded. Maximum column loading, for all
anions, should not exceed about 400 ppm.
12.9 Quality Control
Quality control procedures are specified
in Section 2.6. These include one resolution
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Section 12
Revision 2
Date: 12/86
Page 4 of 8
check, a matrix spike determination, a detec-
tion limit QC sample, QCCS, and duplicate
analysis for each analyte in each solution. The
reagent blank is the DDI water used for water
extraction procedure.
12.10 Procedure
12.10.1 Extraction of Sulfate and
Nitrate by DDI Water
1. Weigh 4.00 g air-dried soil into 100-mL
centrifuge tube. Add 80 ml_ DDI water
and seal the tube.
2. Shake tube and contents for 1 hour on
a reciprocating shaker. To ensure
that soil is not accumulating at the
base of each centrifuge tube, stop the
shaker at 10 to 15 minute intervals
and either invert each tube several
times by hand or mix each tube on a
vortex mixer.
3. Centrifuge for 10 minutes at 510 G. V
the supernatant is not clear, repeat
centrifugation. If it is clear, decant
and save the supernatant.
4. Filter the supernatant solution through
a 0.2 pm membrane filter.
5. Store the solution at 4 °C and analyze
for sulfate and nitrate by ion chroma-
tography within 24 hours (see Section
12.10.3). Immediate analysis is desira-
ble, because biological activity may
reduce the concentration of sulfate
and nitrate in solution. The total
volume of extract is 80 ml. If further
dilution is necessary, take an aliquot
of known volume and dilute in a
volumetric flask. Take this dilution
factor into account when calculating
the concentration.
12.10.2 Extraction of Sulfate by
Sodium Phosphate
Solution
1. Place 4.00 g of air-dried soil into a
100-mL centrifuge tube.
2. Add 20 mL 0.016 M NaH2PO4.
3. Shake tube and contents on a recipro-
cating shaker for 30 minutes. To
ensure that soil is not accumulating at
the base of each centrifuge tube, stop
the shaker after 10 minutes and either
invert each tube several times by hand
or mix each tube on a Vortex mixer.
4. Centrifuge for 10 minutes at 510 G. If
the supernatant is not clear, repeat
centrifugation. If it is clear, decant
supernatant into a clean beaker or
LPE bottle.
5. Repeat extraction and centrifugation
(steps 2, 3, and 4) three times for a
total of four extractions. Combine all
4 supernatants and dilute to 100 mL
6. Prior to analysis, filter the solution
through a 0.2 pm membrane filter.
7. Store the solution at 4 °C and analyze
for sulfate by ion chromatography
within 24 hours (see Section 12.10.3).
Immediate analysis is desirable,
because biological activity in this
nutrient-rich extract may reduce the
concentration of sulfate in solution.
The total volume of extract is 100 mL
If further dilution is necessary, take
an aliquot of known volume and dilute
in a volumetric flask. Take this dilu-
tion factor into account when calculat-
ing the concentration.
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Section 12
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Page 5 of 8
12.10.3 Determination of Sulfate
(SO?) and Nitrate (NOZ) by
Ion Chromatography
This procedure is based on methods
using Dionex ion chromatographs. Other sys-
tems may be used with modifications to the
columns, chromatographic conditions, and
reagents. In these cases, follow the recom-
mendations of the manufacturer. Analyze both
the water and the phosphate extracts of the
soil samples.
The following operating conditions are
recommended for the Dionex-type system.
Other systems require similar conditions.
• Recording system, 10 or 30 pS/cm full
scale deflection; 100 pS/cm for some
cases; linearity should be checked
regularly since this may vary and
cause error.
• Injection loop, 0.05 or 0.10 ml_; 100 ^L
may be preferable for some PO^
samples to reduce pH problems.
• Flow rate, 2.0 to 2.3 mL/min.
• Pressure gauge or similar device, used
as pump-stroke noise suppressor, as
required for unit.
Note: Make certain that pressure does not
exceed the recommendations of the
manufacturer for the column.
1. Operate the fiber suppressor as rec-
ommended by the manufacturer.
Generally, the suppressor must be in
an upright position with regenerant
flowing from bottom to top.
2. Set up the recorders or integrators for
the most sensitive setting for the
sample range being analyzed. Set the
second channel for a high range, or
else perform dilutions when neces-
sary. Operate integrators by following
the instructions of the manufacturer.
3. Pump eluent through the columns.
After a stable baseline is obtained,
adjust the recorder zero to approxi-
mately 10 percent of the chart. Inject
the highest standard. As the highest
standard elutes, adjust the recorder
range to approximately 90 percent of
the chart. Repeat several analyses of
the highest standard to be certain
that the gain is stable and the peaks
are reproducible. Analyze the resolu-
tion standard and determine the reso-
lution. If the PO^- SO^or the NO3'-
SO^ resolution does not exceed 60
percent, replace or clean the separa-
tor column and repeat step 3.
4. Analyze the standards in random
order. Load the injection loop, manu-
ally or via the autosampler, with the
standard to be analyzed. Load five to
ten times the volume required to flush
the sample loop thoroughly; then inject
the standard.
If memory effects are noted for stan-
dards, blanks should be injected be-
fore each analysis. For each analysis,
measure and record the peak height
either manually or with a data system.
If an integrator is available, record the
peak area.
5. Repeat step 4 for analysis of QC
samples, matrix spikes, blanks, and
soil extracts. If using an auto-
sampler, fill it with the samples.
6. Dilute and reanalyze each sample for
which the concentration exceeds the
calibrated range.
7. For each peak, draw a baseline.
Measure the peak height with a clear
plastic ruler and record the peak
height on the strip chart and in a log
book. If an integrator is used, manu-
ally check 5 percent or at least 2 per
batch. Record these peak heights and
peak areas in a log book or in a
computer file. (See Figure 12-1.)
-------
LAB NAME
BATCH ID
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 113
QUALITY CONTROL: ION CHROMATOGRAPHY RESOLUTION TEST
DATLIJK ANALYSTS
Section 12
Revision 2
Date: 12/86
Page 6 of 8
LAB MANAGER'S SIGNATURE
1C Make and Model:
Wl/DD/YR
Concentration
(rcg/L)
Peak Area
(integrator units)
Peak Height
(cm)
NO,
Column Back Pressure (at max. of stroke):
Flow Rate: mL/min
Column Model:
Date of Purchase:
Column Manufacturer:
Column Serial No:
Precolumn in system
Yes
No
MOO x 2(tr2-tri)/(Wi*W2) N03 - P04
Percentage Resolution: 100 x 2(tr3-tr2)/U2+N3) P04 - S04
100 x 2(tr3-tri)/(w1+W3) NOa - S04
The resolution must be greater than 60S.
psi
Test Chromatogram:
(FACSIMILE)
•Calculations may change if order of elution is different from test chromatogram.
Figure 12-1. Ion ehromatography resolution tsat.
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Revision 2
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Page 7 of 8
12.11 Calculations
From the peak heights or peak areas,
calculate the analyte concentration in the ex-
tract as follows:
• Using a graph-Construct a calibration
curve by plotting concentration of
standard versus peak height (or peak
area) for each standard.
Read the concentration of the analyte
directly from the calibration curve.
• Using a linear least squares fit- Equa-
tions used for calculation of the linear
least squares fit are available in most
elementary statistics books. The
linear least squares fit yields the
following parameters: slope (n), inter-
cept (b), error of fit (e), and correla-
tion coefficient (r). The slope and
intercept define a relationship between
concentration of standard i, (x,), and
the predicted instrument response,
y.
mx, + b
(12-1)
A simple rearrangement of Equation
12-1 yields the concentration (X,) corre-
sponding to an instrumental response
of (y,):
= (y, - b)/m
(12-2)
• For nonlinear calibration curves-A
computer routine or microprocessor in
the analyzer may be used to calculate
concentration.
Multiply results for concentration by
the appropriate dilution factor if nec-
essary. Then convert mg S042" to mg
S by multiplying by 0.33379, and con-
vert mg NO3' to mg N by multiplying
by 0.22590.
Convert concentration of analyte in
the soil extract to concentration in the
original soil sample by using the fol-
lowing equation:
Analyte Concentration (mg/Kg soil) =
mg analyte\ / mL extract
1 L
g oven-dried soil wt
1,000 g soil
1,000 mL / \ kg soil
converted from moisture percent procedure
(12-3)
12.12 Precision and Accuracy
The precision and accuracy information
provided is based on analysis of surface water
samples (O'Oell et al., 1984). Analysis of soil
extracts, which have different matrices and
reflect different sample preparation proce-
dures, may not yield results of the same
precision and accuracy as cited here (Table 12-
2). This information is supplied only as an
indication of precision and accuracy.
Table 12-2. Single-Operator Precision and Accuracy
(O'Dell et al., 1984)
Standard
Spike Number of Mean Deviation
Ion (mg/L) Replicates % Recovery (mg/L)
so.'- 10.0
NO/-N 0.50
7
7
111.6
100
0.709
0.0058
12.13 References
Blume, L. J., M. L. Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey, U.S. Envi-
ronmental Protection Agency, Las Vegas,
Nevada. Appendix A In: Direct/Delayed
Response Project Southern Blue Ridge
Province Field Sampling Report. Vol. I:
Field Sampling. U.S. Environmental
Protection Agency.
-------
Section 12
Revision 2
Date: 12/86
Page 8 of 8
Fernandez, I. 1983. Field Study Program Ele-
ments to Assess the Sensitivity of Soils
to Acidic Deposition Induced Alterations
in Forest Productivity. Technical Bulletin
No. 404. National Council of the Paper
Industry for Air and Stream Improve-
ment, Inc., New York, New York.
O'Dell, J. W., J. D. Pfaff, M. E. Gales, and G. D.
McKee. 1984. Technical Addition to
Methods for the Chemical Analysis of
Water and Wastes, Method 300.0, The
Determination of Inorganic Anions in
Water by Ion Chromatography. EPA/ 600/4-84-
017. U.S. Environmental Protection Agency,
Cincinnati, Ohio.
Tabatabai, M. A.. 1982. Sulfur, pp. 501-538 In:
Methods of Soil Analysis: Part 2 Chemi-
cal and Microbiological Properties, Ag-
ronomy Monograph No. 9, 2nd Edition.
A. L. Page, R. H. Miller, and D. R. Keeney
(Eds.) American Society of Agronomy,
Inc./Soil Science Society of America, Inc.,
Madison, Wisconsin.
-------
Section 13
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Date: 12/86
Page 1 of 3
13 Sulfate-Adsorption Isotherms
13.1 Scope and Application
The ability of soil to adsorb sulfate
(SO42) is perhaps the most important factor in
determining if a soil will show a direct or
delayed response to SO42" deposition. The
higher the sulfate-adsorption capacity of a soil,
the greater is its buffering capacity to SO42"
inputs.
Adsorption of inorganic sulfate is primari-
ly affected by soil pH, quantity of Fe and Al
sesquioxides. exchangeable cations, clay
content, and type of clay minerals. Below a
pH of 6.5, sulfate adsorption increases with
decreasing pH; above this pH, sulfate adsorp-
tion is negligible (Tabatabai, 1982). Sulfate-
adsorption capacity can be estimated indirectly
by quantitative determination of the iron- and
aluminum-oxide content (see Fernandez, 1983,
and Johnson and Todd, 1983).
The most direct and effective way to
determine sulfate-adsorption capacity utilizes
sulfate-adsorption isotherms. For this study,
sulfate-adsorption isotherms are developed by
measuring the amount of SO/** remaining in
solution after contact with a soil sample.
These sulfate-adsorption isotherms allow
relative comparisons to be made between
horizons or between pedons. It should not be
inferred that these isotherms quantify the in
situ sulfate-adsorption of soil.
13.2 Summary of Method
Six portions of the same soil sample are
shaken with solution containing 0, 2, 4, 8, 16,
and 32 mg sulfur per liter, respectively. The
mixtures are centrifuged and filtered, and the
resulting filtrate is analyzed for SO42" by ion
chromatography. The difference between the
original concentrations of the sulfur solutions
and the concentrations after this procedure
indicates the sulfur uptake by the soil.
13.3 Interferences
No interferences have been identified.
13.4 Safety
Follow standard laboratory safety prac-
tices and wear gloves, safety glasses, and a
laboratory coat when preparing and handling
reagents. Follow the safety precautions of the
manufacturer when operating the instruments.
13.5 Apparatus and Equipment
• Centrifuge tubes, 100 ml, with screw
caps (50 mL centrifuge tubes with
screw caps, optional).
• Volumetric pipet, 50 ml (pipettor,
optional).
• Vortex mixer.
• Reciprocating shaker.
• Centrifuge.
• Membrane filtration apparatus (Luer-
Lok, glass syringes with membrane
filters or equivalent).
• Ion chromatograph.
13.6 Reagents and Consumable
Materials
• Membrane filters, 0.20 pm pore size.
• Primary sulfate (SO42') solution, (1,000
mg S/L)-Dissolve 3.754 g MgS04 in
DDI water and dilute to 1.000 L
• Adsorption solutions-Dilute 2.00,4.00,
8.00, 16.00, 32.00 mL primary (1,000
mg S/L) solution to 1.000 L in separate
volumetric flasks. It is most
-------
Section 13
Revision 2
Date: 12/86
Page 2 of 3
13.7
convenient if 2- to 4-L batches of ad-
sorption solution can be prepared.
Each solution must be within 5 per-
cent of its theoretical concentration.
Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labo-
ratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the laboratory, all samples are kept sealed
and are refrigerated at 4 °C when not in use.
13.8 Calibration and
Standardization
Calibrate the ion chromatograph as
recommended by the manufacturer. Prepare
working standards fresh daily and verify the
concentrations by ion chromatography. Repre-
pare adsorption solutions if the concentrations
are not within 5 percent of the theoretical
concentrations. Calibration standards must
be from a source independent of the primary
SO4*~ solution prepared for this analysis.
13.9 Quality Control
The concentration of each adsorption
solution must be within 5 percent of its theo-
retical concentration. The quality control re-
quirements are specified in Section 2.6 and
include for each batch, a detection limit QC
sample, QCCS, one resolution check, one SO42"
spike determination, and a duplicate isotherm,
i.e., duplicate analysis of the 0-, 2-, 4-, 8-, 16-,
and 32-mg S/L solutions after shaking them
with portions of the same soil samples.
13.10 Procedure
1. Weigh air-dried sample, equivalent to
10.00 g ± 0.01 g oven-dried soil, and
place it into 100-mL centrifuge tube.
For highly absorbent organic soils,
sample weight may be reduced to 2.50
g ± 0.01 g.
NOTE: If a 50-mL centrifuge tube is used,
reduce sample weight to the equiva-
lent of 5.00 g ± 0.01 g oven-dried soil
and add 25.00 mL solution. For highly
absorbent organic soils, sample
weight may be reduced to 1.25 g ±
0.01 g.
2. Add 50.00 mL of DDI water to cen-
trifuge tube, and cap it. Mix contents
with vortex mixer until no soil adheres
to the bottom of the centrifuge tube.
3. Repeat steps 1 and 2 and substitute
2-, 4-, 8-, 16-, and 32-mg S/L solutions
for DDI water.
4. Shake the samples for 1 hour on a
reciprocating shaker.
5. Centrifuge each sample for 30 minutes
at 510 G, or as appropriate for the soil
sample.
6. Filter supernatant through a 0.20
membrane filter. For some samples
it may be necessary to use a larger
pore pre-filter to prevent immediate
clogging of the 0.20 /L/m filter.
7. Analyze solutions for SO4* by ion
chromatography as described in Sec-
tion 12.10.3. Calibration standards
must be from a source independent
of the primary SO^ solution prepared
for this analysis.
13.11 Calculations
Express results as milligrams sulfur (mg
S) remaining in the supernatant solution.
Report data to three decimal places. If cali-
bration standards are made in terms of mg
^ per liter, then:
-------
Section 13
Revision 2
Date: 12/86
Page 3 of 3
amount of
remaining in solution (mg S/L) =
/concentration of SC^2" mg
( remaining in —) (0.33379)
I solution as 1,000 ml I (13-1)
Calibration standards may be made in
concentration units of milligrams sulfur per
liter.
Also, record each sample weight so that
results may be transformed to reflect milli-
grams sulfur adsorbed by the soil.
13.12 Precision and Accuracy
Precision and accuracy information for
the ion chromatographic determination is given
in Section 12.12.
13.13 References
Blume, L. J., M. L. Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed Re-
sponse Soil Survey, U.S. Environmental
Protection Agency, Las Vegas, Nevada.
Appendix A In: Direct/Delayed Response
Project Southern Blue Ridge Province
Field Sampling Report. Vol. I: Field
Sampling. U.S. Environmental Protection
Agency.
Fernandez, I. 1983. Field Study Program
Elements to Assess the Sensitivity of
Soils to Acidic Deposition Induced Alter-
ations in Forest Productivity. Technical
Bulletin No. 404. National Council of the
Paper Industry for Air and Stream Im-
provement, Inc., New York, New York.
Johnson, D. W., and D. E. Todd. 1983. Some
Relationships Among Fe, Al, C, and SOf
in a Variety of Forest Soils. Soil Sci.
Soc. Amer. J. 47:702-800.
Tabatabai, M. A. 1982. Sulfur, pp. 501-538 In:
Methods of Soil Analysis: Part 2 Chemi-
cal and Microbiological Properties, Ag-
ronomy Monograph No. 9, 2nd Edition.
A. L Page, R. H. Miller, and D. R. Keeney
(Eds.), American Society of Agronomy,
Inc./Soil Science Society of America, Inc.,
Madison, Wisconsin.
-------
14 Total Carbon and Total Nitrogen
Section 14
Revision 2
Date: 12/86
Page 1 of 6
14.1 Scope and Application
Total carbon and total nitrogen in soil
samples are determined with an automated
CHN analyzer. There are many automated
CHN analyzers currently available. The specific
equipment and procedures required will vary
with each model of CHN analyzer. This proce-
dure is based on the operating instructions for
a Perkin-Elmer 240C (McCracken, 1983; The
Perkin-Elmer Corporation, 1981).
Total carbon and total nitrogen are used
to characterize the amount of organic material
in the soil, which is then correlated to other
soil characteristics. Some nitrogen and
carbon may occur in soluble forms such as
Heating the sample to 1,000 °C will oxi-
dize all organic materials and will also decom-
pose carbonate minerals. This releases the
nitrogen and carbon from all sources.
14.2 Summary of Method
A soil sample is oxidized at 1,000 °C for
2 minutes. CO2, H2O, and N2 are then detected
by thermal conductivity.
14.3 Interferences
Moisture in the sample can interfere with
the analysis. Drying the soil at 50 °C prior to
analysis removes most of the excess water
without volatilizing excessive quantities of
organic matter. Consult the instruction manual
provided by the manufacturer for additional
interferences for a specific instrument and
procedure.
The helium must be kept flowing through
the detectors whenever the power is on to
prevent damage to the detectors. The helium
will, however, remove surface water from the
instrument if the instrument is left on standby.
This is overcome by using conditioning sam-
ples before analyzing routine samples and
standards. These condition samples recoat
the system with water so that CO2 and N2 are
not lost to adsorption.
14.4 Safety
Normal laboratory safety precautions
should be followed. Wear protective clothing
and safety glasses when handling reagents or
operating instruments. Heat resistant gloves
may be needed when placing samples in the
furnace. The furnace must be adequately
vented and protected from human contact and
combustible materials.
Follow the safety precautions of the
manufacturer when operating the instruments.
Gas cylinders should be bottled or
chained in an upright position.
14.5 Apparatus and Equipment
NOTE: This list is general for CHN methods.
The specific requirements will vary
with the instrument and procedures
used. Some additional apparatus
may be required, other equipment may
not be needed.
• Hammer mill, ball mill, shatterbox,
agate or mullite mortar and pestle, or
equivalent grinding device.
• Sieve, 60-mesh (0.25 mm).
• Convection oven, equilibrated at 50
°C; with thermometer, 0° to 100 °C
range.
• Compressed air, for cleaning purposes
only.
• CHN analyzer.
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Page 2 of 6
• Data station, micro processor
equipped recording system and inte-
grator, or equivalent digital or analog
system.
• Forceps.
• Tamping rod.
• Bunsen burner.
• Desiccator.
• Microbalance, capable of weighing to
±0.001 mg (±1 /i/g).
• Vials, low carbon, low nitrogen vials
specific for the equipment and proce-
dures used.
14.6 Reagents and Consumable
Materials
• Helium gas, high purity (99.995 mole
percent minimum).
• Oxygen gas, high purity (99.99 mole
percent minimum).
Acetanilide
standard.
NBS-
• Desiccant, anhydrous P2O5 or Ca(OH)2.
• Alumina wool.
NOTE: Precondition alumina wool by holding
it with forceps in a burner flame for a
few seconds.
CAUTION: If heated too long, the alumina
wool will become brittle. Store it in
a desiccator.
14.7 Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1986). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation
laboratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the analytical laboratory, all samples are
kept sealed and are refrigerated at 4 °C when
not in use.
14.8 Calibration and
Standardization
The instrument must be calibrated once
per day or once per batch, whichever is more
frequent.
If (1) the instrument has been out of
operation, (2) the system has been opened, (3)
the combustion or reduction tube, traps, or
scrubbers have been changed, (4) oxygen or
helium has been changed, or (5) any other
change in the gas system has been made
which might affect the detectors, flush the
system by running a blank without using a vial.
When operating the instrument manually, i.e.,
without an autosampler, use no boat or ladle.
Calibration checks include the acetanilide
standard, a blank of alumina wool, and a
quality control calibration standard.
14.8.1 Acetanilide Standards
Acetanilide standards are analyzed to
determine the K-factor. The K-factor is the
microvolts of response per microgram of
sample (/uW/jg) for the given standard.
Accurately weigh approximately 2 or 3
mg ± 0.1 mg acetanilide into sample vial.
Record sample weight. Prepare 5 to 10 repli-
cates. Analyze 2 acetanilide standards before
each batch of approximately 42 samples,
according to the procedure specified in Section
14.10.
K-factors should be reproducible within
the ranges given in Table 14-1. Compute the
mean and standard deviation of K-factors and
note the spread by using the equations given
in Section 14.11. In the absence of other
criteria, Perkin-Elmer lists the following maxi-
mum deviations from the average K-factor for
"an accuracy of ±0.3 percent absolute"; i.e.,
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Table 14-1. Allowable Deviation* In K-Factora'
Table 14-2. Allowable Blank Variations'
Maximum Equivalent
Accuracy deviation range for
Element Level
N
C
5%N
5% N
2% N
1% N
0.5 %N
0.5 %N
50% C
5%C
2%C
% C
desired (pV/jjg)
±0.10 %
±0.05%
±0.05%
±0.05%
±0.05%
±0.01 %
±0.50%
±0.05 %
±0.05%
±0.05
N
N
N
N
N
N
C
C
C
±0.15
±0.08
±0.20
±0.40
±0.70
±0.15
±0.22
±0.22
±0.53
44 (\A
I l.l/*t
acetanilide
10.16-10.57
10.25-10.47
10.10-10.62
9.85-10.87
9.32-11.40
10.16-10.57
70.38-71.81
70.38-71.81
69.31-72.86
K7 49.74 fi*\
w/ ,*T£.mi *t.\K/
%N
%N
%N
%N
%N
% N
%C
%C
%C
%p
o
Element
N
C
N
C
C
N
N
C
" This table
Sample Accuracy
size (mg) desired
3
3
5
5
5
20
20
20
lists the
±0.05
±0.05
±0.05
±0.10
±0.05
±0.05
±0.01
±0.05
% N
%C
%N
%C
%C
% N
% N
%C
maximum allowable
Maximum
Variation (^V)
±11
±33
±19
±108
±54
±77
±15
±218
variation of the
' This table lists the maximum allowable deviations of
the K-factors from the average factors.
blank from the average blank, or from one blank run to
the next.
consistently producing values for acetanilide
within ±0.3 percent of the actual percent for
each element.
Typical K (rough) 20 pV//ig
Maximum deviation
from average ±0.085 pV/pg ±0.20
NOTE: This is the deviation in one direction; therefore,
the total variance may be up to twice the maxi-
mum deviation value.
14.8.2 Blank Samples
Analyze a blank consisting of a vial,
alumina wool, ladle, and the oxygen donor
specified by the manufacturer, if needed.
Alternate blanks with the analysis of samples
or standards to prevent a memory effect.
When blanks are run consecutively, each blank
result following the initial result is lower than
when a blank is run after a sample.
Blanks should be reproducible within the
allowable range given in Table 14-2. Use the
equation given in Section 14.11 to compute
average blank values and variation, and note
the range. In the absence of other criteria,
Perkin-Elmer lists the typical blank values and
ranges as follows.
Element
Typical Blank 100
Maximum Range 50
N
50
30
14.8.3 Calibration Sequence
Analyze at least two acetanilide stan-
dards and two blanks for each batch of sam-
ples in the following sequence: (1) unweighed
sample (-2 mg), (2) blank, (3) unweighed
sample, (4) acetanilide standard (determine K-
factor), (5) blank, continue to alternate deter-
mination of K-factors and blanks, and (6)
acetanilide standard.
The blank values and K-factor must fall
within limits specified in Tables 14-1 and 14-2.
14.8.4 Quality Control Calibration
Standard
Analyze the QCCS after the calibration
sequence is completed and before beginning
routine sample analysis. The QCCS is a well
characterized soil sample whose carbon and
nitrogen values are known. This may be a
purchased sample or one which has been
evaluated many times in the laboratory with
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Page 4 of 6
little or no variation between replications. The
analytical procedure is given in Section 14.10.
14.8.5 Linearity of Calibration
Curve
Determine the linearity of the calibration
curve by analyzing no fewer than three stan-
dards that bracket the expected concentration
range of the samples. When only one stan-
dard material is used for calibration, at least
three samples of standard material of different
weights are prepared such that (1) the amount
of analyte produced by the smallest sample is
approximately equal to the instrumental detec-
tion limit, (2) the amount of analyte produced
by the largest sample is just above that of the
actual samples, and (3) the amount of analyte
produced by the intermediate sample is in the
midrange of the analyte content of the sam-
ples. The correlation coefficient of a graph of
pg of analyte versus sample weight should not
be less than 0.99.
Because elemental analyzers were devel-
oped for analysis of samples with a relatively
high analyte concentration, it is especially
important to verify linearity for low concentra-
tions of analyte.
14.9 Quality Control
In addition to those analyzed during
calibration, more blanks and QCCS are used
during analysis of routine samples to assure
that results continue to be valid. Analyze the
blank sample after every 15 samples, after
completion of analysis of each batch, and
whenever an oxygen donor is added or
changed. Blank values must fall within the
limit specified in Table 14-2. Analyze QCCS
after every ten or fewer samples. QCCS
results must not have a relative standard
deviation greater than 10 percent. If blank or
QCCS values do not meet the specified crite-
ria, recalibrate the instrument and reanalyze all
samples analyzed since the last acceptable
value was obtained for the QC sample type in
question.
The QC requirements are specified in
Section 2.6 and include a detection limit QC
sample, one duplicate analysis, and a matrix
spike determination.
14.10 Procedure
The specific procedural steps will vary
with the instrument and manufacturer. Some
units will not require all the steps, other units
or methods will require additional steps.
14.10.1 Vial Preparation
1. If vials appear deformed, reform them
prior to use. Misshaped vials may
jam the autosampler. Handle vials
with round-tipped forceps. When
lifting a vial with forceps, place the
forceps over the rim of the vial.
Lifting the vial by placing the forceps
around it may deform the vial.
2. Clean vials by blowing out the alumina
wool plugs with compressed air. Heat
the vials in a Bunsen burner flame
until red hot. Store cleaned vials in a
desiccator.
14.1O.2 Sample Preparation
Crush a 2-g aliquot of soil to pass the
60-mesh sieve. Dry the entire aliquot of
crushed soil in a convection oven at 50 °C for
24 hours to reduce excess water. Weigh a
sample of approximately 50 mg accurately to
three decimal places, i.e., ±1 ^g. Adjust the
sample size according to the estimated
amount of organic material: less for high
organic matter soils and more for low organic
matter soils.
14.10.3 Determination of Total
Carbon and Total Nitrogen
If the instrument has been on standby
for more than 1 hour, analyze an unweighed
conditioning sample of approximately 2 mg
acetanilide and then recalibrate the instrument
by using the following procedure:
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Page 5 of 6
1. Place vials in the numbered, lower
sample-loading plate (or the equivalent
for the instrument being used) with
the open end up.
2. Using forceps, place approximately 1
mg preconditioned alumina wool into
each vial. Gently push the alumina
wool to the bottom of the vial with
the flat-ended tamping rod. Caution:
Compressing the fibers of the wool
too much will break them.
NOTE: Not all systems require alumina wool.
3. Weigh the -50 mg sample into the vial
according to the instrument instruction
manual.
4. Replace each weighed sample vial into
lower plate.
CAUTION: Do not lift the tray and replace it
on the table. This action may
result in loss of sample from vial.
Slide tray onto table if you must
move it.
5. Place an additional 1 mg alumina
wool on top of each sample. Use the
tamping rod to gather the wool into
the vial and to push it into place.
6. Inspect each vial for alumina wool
strands that may extend outside the
vial. Remove the extending strands
or push them inside the vial. Holding
the vial up to the light may reveal
strands. Stray alumina wool strands
may damage the autosampler.
7. Adjust sample magazine so that slot
number 1 is over the loading hole.
Place each vial into the magazine.
NOTE: If a sample must be added to the
magazine while the instrument is in
operation, wait until after a sample
has loaded and the magazine has
moved into the next position. Sam-
ples may then be added at any time
until all samples in the batch are
analyzed.
8. Analyze the samples according to the
procedures in the instruction manual
supplied by the instrument manufac-
turer.
9. After analysis is completed, clean the
used vials as described in Section
14.10.1. Discard the used alumina
wool. Place the instrument in the
standby mode.
14.11 Calculations
If a data station or calculator system is
linked to the analyzer, then sensitivity factors
and analytical results for blanks and samples
in weight percent are displayed. If a strip-
chart recorder is used, this information must
be calculated from the microvolt readings.
Report carbon and nitrogen as percent
dry weight to 0.001 percent. Also report K-
factors, blank values, and QCCS values.
The following equations are used to de-
termine K-factors from acetanilide standard
results:
+ Deviation =
[level (%)] (avg. K)
- avg. K
level (%) - accuracy (%)
- Deviation =
[level (%)] (avg. K)
avg. K -
where:
K-factor =
Level (%)
level (%) + accuracy (%)
Volts
(14-1)
(14-2)
\t gram /jg
% of C or N in the compound
The two deviations are not equal. The
allowable negative deviation is less than the
positive deviation. The negative deviation was
used to tabulate values for the maximum devi-
ation as given in Table 14-1.
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Page 6 of 6
Equivalent range =
for Acetanilide
(actual acet. %) (avg. K)
avg. K ± deviation
(14-3)
The calculated values for the equivalent
range for acetanilide in Table 14-1 are based
on the actual positive and negative deviations.
To determine allowable blank variations,
the following equation is used:
Allowable variation
'% accuracy
/sample \ I ) (K-factor in
\wt(jL/g)A 100
(14-4)
14.12 Precision and Accuracy
Accuracy levels vary with sample size
and weight percent for the analyte.
14.13 References
Blume, L J., M. L Papp, K A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed Re-
sponse Project Soil Survey. U.S. Environ-
mental Protection Agency, Las Vegas,
Nevada. Appendix A In: Direct/Delayed
Response Project Southern Blue Ridge
Province Sampling Report. Vol. I: Field
Sampling. U.S. Environmental Protection
Agency.
McCracken, R. E. 1983. In-House Operations
Manual lor the Perkin-Elmer 240 CHN
Analyzer. Agronomy Analytical Laborato-
ries, Cornell University, Ithaca, New York.
Perkin-Elmer Corporation, The. 1981. Instruc-
tions: Model 240C Elemental Analyzer.
The Perkin-Elmer Corporation, Norwalk,
Connecticut.
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Page 1 of 5
15 Inorganic Carbon
15.1 Scope and Application
This method is for the coulometric analy-
sis of fine earth and rock fragment fractions
for inorganic carbon. The analysis is per-
formed if the qualitative test for inorganic
carbon performed at the preparation laboratory
is positive or if the water pH of the sample is
greater than or equal to 6.0.
The effectiveness of the coulometric
technique stems from its basic reliance on
electrolytic measurement. Because it requires
relatively large currents as compared with
other methods and an unpolarized working
electrode, a coulometric method is capable of
precision to ±0.1 percent or better and is intrin-
sically accurate. The sensitivity of a coulo-
metric method is high; by using low currents
and microapparatus, good precision can be
obtained at sample concentrations of 10"4 M
and below (Strobel, 1973). There are some
limitations on the use of the coulometric
technique because of restrictions imposed by
the electrolytic process, but these limitations
are not of consequence in soil solution
analysis.
15.2 Summary of Method
The less than 2-mm fraction and the rock
fragment fraction of a soil sample are ana-
lyzed separately for inorganic carbon. Before
analysis, the rock fragment fraction is crushed
with a jaw crusher, then is powdered to pass
a 60-mesh sieve by using either a pulverizer, a
hammer mill, or an equivalent unit. The sam-
ple is placed in the sample tube of the coulo-
meter, either directly or within a weighing boat,
is treated with acid, and is heated to evolve
carbon dioxide. When the coulometric reading
in micrograms of carbon is relatively steady,
the analysis is complete. The method is from
Coulometrics, Inc., (1985).
15.3 Interferences
No interferences have been identified.
15.4 Safety
Wear protective clothing and safety
glasses when preparing reagents, especially
when concentrated acids and bases are used.
The use of concentrated acid and hydroxide
solutions should be restricted to a hood.
Follow the safety precautions provided by the
manufacturer when operating the coulometer.
15.5 Apparatus and Equipment
• Jaw crusher.
• Riffle splitter, Jones-type.
• Pulverizer, hammer mill, shatter box, or
equivalent.
• Sieve, 60-mesh.
• Coulometer.
• Mineral carbon apparatus (see Figure
15-1).
• Weighing boats, carbonate-free.
• Sample tubes, as recommended by
the manufacturer.
• Repipet, adjustable to 2 mL, or equiva-
lent unit.
• Heating unit.
• Coulometer accessories as recom-
mended by manufacturer.
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Section 15
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Page 2 of 5
A. Main Power
B. Heater Control
C. Heat Indicator Light
D. Flow Meter
E. Heater and Shield
F. Main Support
G. Air Scrubber
H. Sample Tube
I. Condenser
J. Adaptor Tube
K. Septum
L. Sample Scrubber
M. Analysis Air Line
N. Condenser Air Line
0. Acid Dispenser
P. Scrubber Outlet to Coulometer
Q. Sample Purge Tube
R. Acid Inlet
S. Purified Air Inlet
T. Sample Air Outlet
Figure 15-1. Mineral carbon apparatus.
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Page 3 of 5
15.6 Reagents and Consumable
Materials
• DDI water-Water used for preparing
or diluting reagents or samples must
be double-distilled, double-deionized
(DDI), or deionized and distilled to
meet purity specifications for Type II
Reagent Water given in ASTM D 1193
(ASTM, 1984).
• Acid solution for CO2 evolution-A
variety of mineral acids may be used
for CO2 evolution. Depending on the
sample type, certain acids have ad-
vantages over others. One of the
following acid solutions is suggested
with the conditions noted.
1. Sulfuric acid (H^OJ-Add 58 ml_ of
concentrated H2SO4 to 500 mL DDI
water in a 1.00 L volumetric flask.
Allow solution to cool, then dilute
to volume with DDI water. This is
about 2 N H2SO4. When H2SO4
solution is used for CO2 evolution,
precipitation of sulfates may tend
to occlude some carbonate.
2. Hydrochloric acid (HCI)--Add 200
mL of concentrated HCI to 600 mL
DDI water in a 1.00 L volumetric
flask. Allow solution to cool, then
dilute to volume with DDI water.
This is about 2 N HCI. When HCI
solution is used for CO2 evolution,
care must be taken to ensure that
HCI from the solution does not
overload the scrubber and enter the
coulometer.
• Calcium carbonate (CaCOJ, primary
standard grade.
• Potassium hydroxide (KOH), solution
for air scrubber-Dissolve 100 grams
KOH in 100 mL C02-free DDI water to
produce a solution that is 50 percent
KOH by weight. This KOH solution
15.7
remains effective for 1 to 2 weeks in
regular use. The air bubbling through
the solution must be well-dispersed
for efficient removal of CO2.
Solution for sample scrubber tube--
Trie common volatile acidic gases
from acid treatment of mineral materi-
als can be removed with either of the
following:
1. Saturated silver sulfate (Ag2SO4)
containing 3 percent H2O2 and
adjusted to pH 3~Dissolve about
1.5 grams Ag2SO4 in 90 mL DDI
water to produce a saturated silver
sulfate solution. Add 10 mL 30
percent H2O2. Adjust to pH 3 with
H2SO4. Do not use HCI because it
will precipitate AgCI.
2. Potassium iodide (KI), 50 percent
by weight adjusted to pH 3 Dis-
solve 100 g KI in 100 mL DDI wa-
ter. Adjust to pH 3 with dilute HCI.
Antifoam agent-Hither of the follow-
ing anti-oxidants may be added to the
sample if there is a concern about
rapid oxidation and foaming of organ-
ic materials because of H2O2.
1. Stannous chloride (SnCI2).
2. Ferrous sulfate (FeSOJ.
Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation labo-
ratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the analytical laboratory, all samples are
kept sealed and are refrigerated at 4 °C when
not in use.
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Page 4 of 5
15.8 Calibration and
Standardization
Before and after each analytical batch,
analyze a series of standards by following the
procedure given in Section 15.10. The high and
low standards should bracket the expected
concentrations of inorganic carbon in the
samples. Use the primary standard grade
CaCO3.
15.9 Quality Control
Quality control requirements are specified
in Section 2.6 and include a detection limit QC
sample, QCCS, a duplicate analysis, and a
matrix spike determination.
15.10 Procedure
1. Pass the rock fragment fraction
through the jaw crusher. By using the
riffle splitter, obtain a 100-g sub-
riffle splitter,
sample.
Place the 100-g aliquot of rock frag-
ments in the pulverizer or hammer mill
and grind the fragments to a powder.
Pass the powder through a 60-mesh
sieve. If necessary, regrind any
material retained by the sieve.
2. For both the powdered rock fragments
and the <2-mm soil fraction, weigh an
aliquot of sample that contains 1 to 3
mg of mineral carbon. Either weigh
sample into a porcelain boat or other
carbonate-free sample carrier and
place the entire carrier into the sample
tube; or weigh sample directly into the
sample tube.
NOTE: The sample tube must be free of
residual acid.
3. Check the system for leaks. The
system must be leak-free for proper
functioning.
4. Dispense approximately 2 ml acid into
the sample tube from the repipet.
5. Place sample tube on the heating unit
and adjust the temperature so that
fumes from the acid do not overload
the scrubber and enter the coulometer.
6. Allow CO2 to evolve from the sample
until the coulometer gives a relatively
steady reading.
NOTE: The very high sensitivity of the coulo-
meter can make a relatively stable end
point appear somewhat unstable, e.g.,
for a 50-mg sample, 5 ug represents
only 0.01% C.
7. Record the time required for analysis
of the samples, standards, and
blanks. Also, record the analyte
concentration as weight percent
carbon (wt % C).
8. Reset coulometer and analyze the next
sample.
15.11 Calculations
% inorganic
carbon =
(micrograms C - blank)
(100)
micrograms of sample.
15.12 Precision and Accuracy
No precision or accuracy data are cur-
rently available.
15.13 References
American Society for Testing and Materials.
1984. Annual Book of ASTM Standards,
Vol. 11.01, Standard Specification for
Reagent Water, D1193-77 (reapproved
1983). ASTM, Philadelphia, Pennsylvania.
Blume, L J., M. L. Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. U.S.
Environmental Protection Agency, Las
Vegas, Nevada. Appendix A In: Direct/-
Delayed Response Project Southern Blue
Ridge Province Field Sampling Report
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Page 5 of 5
Vol. I: Field Sampling. U.S. Environ- Strobel. HA 1973. Chemical Instrumentation:
mental Protection Agency. A Systematic Approach to Instrumental
Analysis, Second Edition. Addison-Wes-
Coulometrics, Inc. 1985. CoulometricInorganic ley Publishing Company, Inc., Reading,
Carbon Determination. Coulometrics Massachusetts.
Inc., Golden, Colorado.
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Section 16
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Page 1 of 3
16 Total Sulfur
16.1 Scope and Application
Total sulfur in soil samples is determined
with an automated sulfur analyzer by combus-
tion of the sample at approximately 1,550 °C.
This procedure is based on the operating
instructions for a LECO 763-300 sulfur analyzer
(LEGO, undated).
The determination of total sulfur is
necessary to establish a mass-balance rela-
tionship between naturally occurring sulfur and
sulfur inputs from acidic deposition.
16.2 Summary of Method
The sample is placed in a ceramic cruci-
ble with Fe, Sn, and Cu catalysts, is covered
with a porous cover, and is heated to a maxi-
mum of 1,550 °C in a high-frequency, timed
induction furnace. The combustion of the
sample liberates SO2 which is then determined
by an infrared detector or by another method
which meets the required detection limit.
16.3 Interferences
If the soil has a high organic matter
content, sample size must be reduced to
prevent an explosion in the combustion furnace
when heat and oxygen are added. Also, high
organic matter content may delay combustion.
Low recovery of sulfur may occur, since the
organic matter will consume oxygen to pro-
duce CO2 and nitrogen oxides in addition to
SO2.
If detection of the analyte is by titration,
other volatile products may interfere with the
titration of S02 by increasing the titer and,
therefore, will produce high results.
16.4 Safety
Wear protective clothing and safety
glasses when handling reagents or operating
instruments. Heat resistant gloves may be
needed when placing samples in the furnace.
The furnace must be adequately vented and
protected from human contact and combusti-
ble materials. Follow the safety precautions
of the manufacturer when operating the
instruments.
Gas cylinders should be bolted or
chained in an upright position.
Fumes of magnesium oxide (MgO) are
toxic. Magnesium perchlorate [MgfCIOJJ is
a fire and explosion hazard when it comes in
contact with organic materials.
16.5 Apparatus and Equipment
• Induction furnace (LECO model 763-
300 or equivalent).
• Infrared gas analyzer.
• Chart recorder and integrator.
• Oxygen tank.
• Sampling scoops (LECO or equiva-
lent).
• Balance, analytical, accurate to
±0.0001 g (±0.1 mg).
16.6 Reagents and Consumable
Materials
• Crucibles with lids, sulfur free and
appropriate for use with the equip-
ment used.
• Anhydrous magnesium perchlorate
[MgfCIOJz], 10 to 20 mesh, or equiva-
lent desiccant specified by manufac-
turer for drying gases after combus-
tion and prior to detection.
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Page 2 of 3
• Potassium aluminum sulfate
• 12H2O], standard, ACS reagent grade
or other standard.
NOTE: Certain instruments may not require
the following materials. Refer to the
instructional manual for the specific
instrument.
• Magnesium oxide (MgO), powder, ACS
reagent grade, low in sulfur.
• Iron chip accelerator.
• Copper metal accelerator.
• Granular tin accelerator.
16.7 Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation
laboratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
In the analytical laboratory, all samples are
kept sealed and are refrigerated at 4 °C when
not in use.
16.8 Calibration and
Standardization
The instrument must be calibrated once
per day or once per batch, whichever is more
frequent. Analyze a series of KAI(SO4)2«12H2O
standards by the procedure given in the in-
struction manual for the specific instrument.
KAI(SO4)2» 12H2O is 13.52 percent sulfur by
weight. Determine the weights of standard to
use so that the analytical results for the
standard bracket the expected sulfur content
of the samples.
If sulfur content of samples is low, other
standard materials may be used. Cement or
rock standards are suggested if clay or soil
standards are unavailable.
Determine the linearity of the calibration
curve by analyzing no fewer than three stan-
dards that bracket the expected concentration
range of the samples. When only one stan-
dard material is used for calibration, at least
three samples of standard material of different
weights are prepared such that (1) the amount
of sulfur produced by the smallest sample is
approximately equal to the instrumental detec-
tion limit, (2) the amount of sulfur produced by
the largest sample is just above that of the
actual samples, and (3) the amount of sulfur
produced by the intermediate sample is in the
mid-range of the analyte content of the sam-
ples. The correlation coefficient of a graph of
jug of sulfur versus sample weight should not
be less than 0.99.
16.9 Quality Control
Quality control requirements are specified
in Section 2.6 and include a detection limit QC
sample, QCCS. one duplicate analysis, and a
matrix spike determination.
16.10 Procedure
16.10.1 Sample Preparation
Note: The following steps outline a sample
preparation procedure. Refer to the
instruction manual for the instrument
specific sample preparation procedure.
1. Place 1 large scoop of MgO, about 0.3
to 0.35 grams, in the bottom of the
crucible. After adding each compo-
nent, gently shake the crucible to
distribute contents over the bottom.
2. Weigh 0.500 grams air-dried mineral
soil into the crucible. A smaller sam-
ple may be needed if the soil is high
in organic matter (see Section 16.3).
A sample size of 0.200 to 0.300 g is
suggested for organic soil. Material
dried at 60 °C should not be used
since some forms of sulfur may be
volatile.
3. Add 1 more large scoop of MgO.
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Page 3 of 3
4. Add 1 small (0.2 ml) heaping scoop of
Fe chips, evenly distributed to cover
MgO.
5. Add 1 small (0.2 ml) heaping scoop of
Sn granules, evenly distributed to
cover Fe chips.
6. Add one Cu ring.
7. Place a porous cover on the crucible.
(Cover may be turned over and reused
once.)
16.10.2 Determination of Sulfur
Follow the procedure outlined in the
operating manual of the specific instrument.
Generally the following steps are necessary:
1. Up to five analyses are run to condi-
tion the instrument at the beginning of
the day, whenever the instrument has
been idle for a period of time, or
whenever new desiccant has been
installed.
2. Periodically, check the desiccant
(magnesium perchlorate) in the drying
tube and replace it whenever the first
few centimeters become wet. If it
becomes too wet, the baseline may
shift as the sample starts to heat,
and this shift will be integrated as
sulfur.
3. To prolong the life of the combustion
tube and refractory liner, the furnace
should remain at operating tempera-
ture at all times; however, to conserve
energy the furnace temperature may
be reduced slightly. Refer to instruc-
tional manual for specific information.
4. If detection of analyte is by titration
rather than by an infrared detector,
the titration chamber and associated glass-
ware should be cleaned with acetone or
concentrated HCI periodically.
16.11 Calculations
An instrument with internal calibration
may report results in weight percent sulfur (wt
Data from other instruments may require
a series of calculations to express results as
weight precent sulfur. Compare the sample
results to a standard curve (see Section 16.8).
Determine the sulfur content in milligrams,
then:
% Sulfur
mg S
|(g oven-dried
soil) (1,000)
1(100)
(16-1)
16.12 Precision and Accuracy
No precision or accuracy information is
available at this time.
16.13 References
Blume, L J., M. L Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. U.S.
Environmental Protection Agency, Las
Vegas, Nevada. Appendix A In: Direct/-
DelayedResponse Project Southern Blue
Ridge Province Field Sampling Report.
Vol. I: Field Sampling. U.S. Environ-
mental Protection Agency.
LECO. Undated. Instruction Manual for LECO
Sulfur Systems. LECO Corporation, St.
Joseph, Michigan.
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Page 1 of 12
17 Semiquantitative Analysis by X-Ray Powder Diffraction of
the <2~mm and <0.002-mm Fractions of Soil
17.1 Scope and Application
This method is restricted to the analysis
of the fine earth fraction (<2 mm) and the clay
fraction (<0.002 mm) of soil. Nonclay miner-
als are often found in the <0.002-mm fraction,
and their identification is essential to under-
standing the chemistry of the inorganic constit-
uents of soil. Bulk soil mineralogy provides
information about the weathering environment
in the soil and about the parent materials from
which the soil developed.
17.2 Summary of the Method
Randomly oriented powder mounts are
prepared for a multiphase reference standard
and for the fine earth and the clay mineral
fractions of each soil sample. Each material
is pulverized to a particle size of less than 2
mm and corundum is added as an internal
standard. The mounted materials are analyzed
by X-Ray diffraction (XRD). The resulting dif-
fraction patterns, or diffractograms, are in-
dexed and labeled for unambiguous identi-
fication of sample type and instrumental
settings. By comparing the sample diffracto-
grams with the diffractogram obtained for the
multiphase reference standard, a semiquantita-
tive estimate can be made for each mineral
component of each sample.
Oriented mounts of the clay fraction of
each soil sample are prepared from clay
suspensions saturated with either Mg2+ or K+.
Standard treatments of glycolation or heating
are performed on the oriented mounts. Each
mount is then analyzed by XRD. The resulting
diffraction patterns are indexed and used to
identify the clay minerals occurring in each
sample.
17.3 Interferences
To reduce the intensity variation due to
particle size, all samples must be reduced to
a particle size of <0.002 mm.
17.4 Safety
Follow standard laboratory safety prac-
tices and wear a laboratory coat, gloves, and
safety glasses when preparing and handling
reagents. Many metal salts are extremely
toxic and may be fatal if swallowed. Wash
hands thoroughly after handling any metal
salts.
Follow the safety precautions of the
manufacturer when operating instruments.
Personnel working with the X-Ray diffrac-
tometer must wear individual radiation badges.
Check radiation badges on a monthly basis to
assess exposure. In addition, on a monthly
basis, use a detector to check for radiation
leaks from the instrument.
17.5 Apparatus and Equipment
• Riffle-splitter, Jones-type.
• Ring and puck pulverizer, titanium
carbide or equivalent.
• Automated mortar and pestle, agate
or mullite.
• Graduated cylinder, 250 mL, fitted with
a stopper.
• Ultrasound, bath or horn-type.
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Page 2 of 12
NOTE: If the horn type is used, use the
lowest setting possible. The heat
generated at the higher wattages can
alter some clay types.
• Thermometer, range 0 to 50 °C.
• Sample holder for randomly oriented
powder mounts.
• Glass slide, rectangular.
• X-Ray powder diffraction unit with Cu-
radiation tube, x-, y-plotter, solid state
pulse height analyzer, peak area inte-
gration capability, rotating and oscil-
lating stage, diffraction pattern library,
and data analysis software.
• Wiggle Bug mixer.
• Balance, accurate to ±0.1 g.
• Centrifuge tubes, plastic, 100 ml_, with
screw caps.
• Centrifuge tubes, glass, 50 mL
• Centrifuge, International No. 2 with
No. 240 head, or equivalent.
• Reciprocating shaker.
• Hypodermic syringes, plastic, 10 mL
• Screen, 80-mesh.
• Diamond or carbide scribe.
• Glass slides, circular, 32 mm.
• Desiccator.
• Convection oven.
• Thermometer, range 0 to 100 °C.
• Muffle furnace.
• Eyedropper or pipet.
• Freeze-dryer.
• Dialysis tubing.
17.6 Reagents and Consumable
Materials
• Reference minerals, as required to
match the minerals identified or ex-
pected) in the samples.
1. Quartz.
2. Albite.
3. Orthoclase.
4. Hornblende.
NOTE: A source for these reference minerals
is Wards Natural Science Establish-
ment, Inc., 5100 West Henrietta Road,
P.O. Box 92912, Rochester, New York
14692-9012, telephone: 716/359-2502;
or 11850 East Florence Avenue, Santa
Fe Springs, California 90670-4490,
telephone: 213/946-2439.
5. Montmorillonite.
6. Illite.
7. Kaolinite.
NOTE: These reference clays are available
from the Clay Minerals Society Source
Clays Repository, Department of
Geology, University of Missouri -
Columbia, Columbia, Missouri 65201,
telephone: 314/882-3785.
• Corundum, Linde semiconductor grade
&-AI2O3,1 micron (available from Union
Carbide).
• Calibration standard.
1. Silicon powder, National Bureau of
Standards (NBS) standard reference
material SRM 640A or SRM 640B.
2. Arkansas novaculite, quartz standard.
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Page 3 of 12
NOTE: This standard is available from the
Gem Dugout, 1652 Princeton Drive,
State College, Pennsylvania 16803,
telephone 814/865-5782.
• Double-deionized water (DDI H2O) or
equivalent.
• Sodium hexametaphosphate
(NafPOJe), 10 percent solution-Dis-
solve 100 g Na(PO3)6 in DDI H2O.
Dilute to 1.0 L
• Magnesium chloride (MgCy, reagent
grade, 1.0 N-Dissolve 47.6 g MgCI2 in
DDI H2O. Dilute to 1.0 L.
• Ethanol (C2H5OH), U.S.P. grade.
• Methanol (CH3OH), reagent grade.
• Potassium chloride (KCI), reagent
grade, 1.0 N-Dissolve 75.6 g KCI in
DDI H2O. Dilute to 1.0 L
• Ethylene glycol (CH2OHCH2OH), techni-
cal grade.
• Cation exchange resin, Rexyn 101 (H)
(available from Fisher Scientific Co.,
Pittsburgh, PA 15219) or equivalent.
• Silica gel desiccant.
• Hydrogen peroxide (H2OJ, reagent
grade, 30% solution.
• Sodium acetate (NaC2H3O2), reagent
grade, 1.0 N-Dissolve 82.0 g NaC2H3O2
in DDI H2O. Dilute to 1.0 L.
17.7 Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection, all
samples are delivered to the preparation
laboratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
Once the mineralogical samples are aliquoted,
the mineralogical samples do not need to be
refrigerated. In the mineralogical laboratory,
all samples are kept sealed when not being
used.
Label all slides prepared for XRD by
etching the sample number on the back of
the glass slide with a diamond or carbide
scribe. Position the etching so that the vacu-
um seal on an automated XRD sample changer
is not affected. Keep each slide in a desiccator
or dry slide box, whichever is appropriate,
when the slide is not being analyzed.
17.8 Calibration and
Standardization
Use copper Ka1 radiation for XRD analy-
sis. Set the power supply at an optimal
setting according to the guidelines of the
manufacturer. Set the goniometer speed to
resolve low intensity peaks which are 10
percent of the maximum response.
Store the patterns in the computer for
later printout.
Perform an initial alignment of the goni-
ometer by X-Raying the silicon powder calibra-
tion standard NBS SRM Number 640 A or 640
B. To verify the alignment of the goniometer
and the intensity of the X-Ray tube, the silicon
powder calibration standard must be X-Rayed
midway through the analyses and after the
final sample. Corundum, i.e., Linde a-AI2O3, or
an Arkansas novaculite standard are accept-
able substitute calibration standards.
Because each diffractometer yields
slightly different patterns and reflection intensi-
ties, reference intensity ratios (RIR) must be
established for the multiphase reference stan-
dard. This reference standard contains corun-
dum as a matrix flushing agent (Chung, 1974).
Other components are chosen to match those
minerals identified (or expected) in the sam-
ples, and may include quartz, albite, ortho-
clase, hornblende, montmorillonite, illite, or
kaolinite. When analyzing randomly oriented
powder mounts of the <2-mm fractions and
the <0.002-mm fractions, the reference stan-
dard must be X-rayed prior to sample analysis
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Page 4 of 12
and after every 60 samples. The calculation of
RIR and the percentages of each mineral in
each sample must be based on the average
analyses of the reference standard that brack-
et the sample analyses.
17.9 Quality Control
17.9.1 Sample Preparation
Before removing an aliquot for prepa-
ration, each bulk sample must be passed
seven times through a Jones-type riffle-splitter
to achieve homogeneity.
Each batch of 26 samples must be
prepared by the same technician.
A majority of the particles within each
sample (approximately 70 percent by volume)
must have a uniform particle size of < 0.002
mm prior to analysis to reduce linear absorp-
tion and primary extinction effects. Use a ring
and puck pulverizer of titanium carbide or
equivalent for the initial particle size reduction
to 0.040 mm. Use an automated mortar and
pestle of agate or mullite for the final particle
size reduction to <0.002 mm. Add ethanol to
prevent excessive heating. In general, not
more than 60 minutes grinding per sample is
necessary. For each sample, perform a check
on the particle size distribution of the first five
of the pulverized samples in the first batch.
The distribution will determine the average
grinding time necessary to attain the required
particle size.
17.9.2 Sample Analysis
For randomly oriented powder mounts,
the multiphase reference standard and each of
the routine samples contains corundum as an
internal standard.
17.9.3 Indexing of Diffractograms
Each pattern must be indexed. Indexing
includes marking the degrees 23 in 1 degree
increments from the starting point to the
ending point of the pattern and labeling each
peak with the degree 20 position, the equiva-
lent angstrom units, the mineral name, and the
number of the JCPDS card (JCPDS, 1985/1986)
used to identify each mineral.
In addition, the following must be re-
corded on each pattern:
• sample number.
• size fraction.
• type of mount, i.e., oriented or ran-
domly oriented.
• treatments.
• date of analysis.
• goniometer speed.
• scale.
• millivolt (mV) or kilovolt (kV), milliam-
pere (mA), and time constant settings.
17.10 Procedure
17.10.1 Preparation and Analysis
of the Multiphase
Reference Standard
NOTE: The reference standard contains
corundum as a matrix flushing agent.
Choose other components to match
those minerals identified (or expected)
in the samples. Match the crystallinity
of the minerals in the reference stan-
dard as closely as possible to that of
the minerals in the samples.
1. Pulverize each of the reference miner-
als to a particle size of <0.002 mm.
Use a ring and puck pulverizer of
titanium carbide or equivalent for the
initial particle size reduction to 0.040
mm. Use an automated mortar and
pestle of agate or mullite for the final
particle size reduction to <0.002 mm.
Add ethanol to prevent excessive
heating. In general not more than 60
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Page 5 of 12
minutes grinding per sample is
necessary.
2. Test the particle size distribution of
each mineral by the sedimentation
technique. This gravimetric technique
allows particles to separate in a col-
umn of water according to their sizes.
Add a 1.0-g aliquot of the pulverized
material to a 250-mL graduated cylin-
der equipped with a stopper. Pour 5
mL sodium hexametaphosphate solu-
tion into the cylinder. Add DDI water
to a depth of 11.0 cm. Place the un-
stoppered cylinder in an ultrasound
bath for 5 minutes to disaggregate
the particles.
Place a mark on the graduated cylin-
der 10.0 cm below the surface of the
suspension. Stopper the cylinder and
invert it three times to thoroughly mix
the suspension. Then set the cylinder
down on a stable horizontal surface
and immediately note the time. For
the duration of the settling, the room
temperature must be held at a con-
stant 22 °C. If, by a visual estimate,
more than 2 percent of the pulverized
sample appears on the bottom of the
graduated cylinder prior to 7 hours
and 38 minutes elapsed time (Muller,
1967), the sample must be repul-
verized, and the particle size must be
checked again.
NOTE: To accustom the analyst to visualizing
2 percent of 1.0 g, weigh 0.02 g of
any sample composed of clay-sized
particles, i.e., <0.002-mm diameter, to
use as a comparison.
3. Weigh exactly 0.50 grams of each
pulverized mineral including the corun-
dum (alpha-AlgOg). Because it comes
from the manufacturer in the 1 micron
particle size, there is no need to pul-
verize the corundum. Combine the
minerals in a polyethylene container
and mix well. This mixture is the
multiphase reference standard, subse-
quently referred to as the reference
standard.
4. Utilize the free-falling method (NBS,
1971) to prepare a randomly oriented
powder mount of the reference stan-
dard. Clamp a glass slide over the
side of an open-ended sample holder
to form a cavity. Allow the powdered
standard to fall into the cavity while
the holder is in a vertical position.
Place the slide in the horizontal posi-
tion (parallel to the plane of the hold-
er) and remove the glass slide gently.
Roughen the surface of the mounted
sample with a single pass of emery
paper to encourage random orienta-
tion of the surface layers.
5. X-Ray the sample from 2° to 65° 29
while the stage is set to rotate and
oscillate. The oscillation subjects the
sample to travel in an arc which,
combined with the rotation, causes
the particles in the sample to ap-
proach a random orientation. This
helps to eliminate some of the orien-
tation caused by the sample prepara-
tion. Set the diffractometer to inte-
grate the area under the peaks. Store
the pattern digitally for later printing.
6. Determine the reference intensity
ratios (RIR) for each mineral in the
reference standard by measuring the
integrated area under the curve of the
strongest peak of each mineral (I,)
and of the matrix flushing agent,
corundum (Ic). If there is overlap in
the peaks, use the next strongest
peak of the mineral being measured.
Average duplicate readings for each
peak and compute the RIR (equation
17-1) for the strongest peak of each
mineral.
I,
RIR =
I,
(17-1)
This value is the RIR used for the
SQXRD computations.
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Page 6 of 12
List the RIR values on DDRP Form 400
(see Appendix D).
17.10.2 Preparation of Randomly
Oriented Powder Mounts
from the <2-mm Fraction
of Soil Samples
1. Homogenize the sample by passing it
through a Jones-type riffle-splitter
seven times.
2. Take 6.0 g of the <2-mm soil sample
and pulverize it to a particle size of
<0.002 mm in two steps. First, use a
ring and puck pulverizer of titanium
carbide or equivalent to reduce the
particle size to about 0.040 mm. Then
transfer the sample to an automated
mortar and pestle of agate or mullite.
Add 20 mL of ethanol to the soil sam-
ple and grind for 12 minutes. Allow
the sample to air dry.
3. Check the particle size of the first five
routine samples of the first batch by
sedimentation, as described in Section
17.10.1, step 2.
4. Weigh 4.0 g of the <2-mm soil which
has been pulverized to <0.002 mm,
and add 1.0 g of corundum. Mix well
in a Wiggle Bug mixer for approxi-
mately 20 to 30 seconds. Because
mixing will generate enough heat to
alter some clay minerals, excessive
time in the mixer should be avoided.
5. Prepare a randomly oriented powder
mount from the mixed sample in the
same manner as described in Section
17.10.1, step 4.
6. X-Ray the sample from 2° to 65° 29
while the stage is set to rotate and
oscillate. Set the diffractometer to
integrate the area under the strongest
peak of each mineral in the sample.
Store the pattern digitally for later
printing.
17.10.3 Separation of <0.002-mm
Fraction from the <2-mm
Fraction of Soil Samples
1. Place 10.0 g of the <2-mm soil into
each of four 100-mL centrifuge tubes.
To each tube, add 5 ml sodium meta-
phosphate solution, and bring the
volume of the suspension to 50 mL
with DDI water. Disaggregate the
material by shaking overnight (>15
hours) on a reciprocating shaker.
Then hold the centrifuge tubes in the
ultrasonic bath for 5 minutes to as-
sure dispersion of the clay-sized parti-
cles.
2. Centrifuge the suspension for 4 min-
utes, 30 seconds at 750 rpm on an
International No. 2 centrifuge with a
No. 240 head. The supernatant will
contain the <0.002-mm fraction, and
the sediment will contain the > 0.002-
mm fraction.
3. Into a large container labeled with the
sample number and "<0.002-mm,"
decant the supernatant to a depth of
10.0 cm as measured from the surface
of the supernatant.
4. Add 5 mL sodium hexametaphosphate
solution and DDI water to replace the
solution decanted after each centrifug-
ing. Resuspend the sediments in each
centrifuge tube by sonicating the
sample in the ultrasound bath.
5. Repeat steps 2, 3, and 4 until 3.0 g of
<0.002-mm material is available for
analysis.
6. Remove the sodium hexametaphos-
phate and other dissolved salts by
dialysis, centrifugation, and decanta-
tion or by successive centrifugation,
decantation, and resuspension. The
<0.002-mm material produced here
will be used to make both oriented
mounts and randomly oriented
mounts.
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Page 7 of 12
a. Pour the <0.002-mm suspension
into dialysis tubing. Dialyze
against DDI water for 96 hours.
Change the water in the dialysis
bath every 12 hours over that time
period. Resuspend the <0.002-mm
material by holding the dialy-
sis tubing in an ultrasound bath
of DDI water for 15 minutes.
Pour the suspension into 100-mL
test tubes, centrifuge the samples,
decant the supernatant, and trans-
fer the sediment to a holding con-
tainer.
b. Pour the <0.002-mm suspension
into four 100-mL test tubes and
centrifuge the samples until the
supernatant is clear. Decant and
discard the supernatant. Add
DDI water to replace the superna-
tant removed. Resuspend the sed-
iment by holding the centrifuge
tubes in an ultrasound bath for 15
minutes. Again centrifuge the sus-
pension until the supernatant is
clear. Again decant and discard
the supernatant. Repeat this pro-
cedure a third time, then transfer
the sediment to a holding contain-
er. Continue processing until the
entire suspended <0.002-mm frac-
tion has been washed.
7. When a sample contains a large a-
mount of organic material it may be
necessary to remove this material to
eliminate an aggregating effect. Use
the following technique:
a. Remove the organic material by
using a 30% solution of H2O2. The
soil-to-water ratio of the sample
should be 1:1 and not more than
1:2. H2O2 is most efficient in oxi-
dizing the organics in a medium
when the pH is slightly acidic. Use
litmus paper to test the acidity of
the suspension, and add a few
drops of a 1.0 N solution of sodium
acetate to acidify the suspension if
necessary. Add H2O2 to the sus-
pension in increments of 5 ml_ or
less, stir the suspension during
and after each addition, and allow
any effervescence to subside be-
fore continuing the additions. Plac-
ing the suspension in a cold bath
will help control strong reactions.
Continue adding the H2O2 in small
quantities until no more reaction is
observed.
b. Transfer the beaker to a hot plate
set at 50 °C. Do not exceed 50 °C
because some clays such as
halloysite are susceptible to crys-
talline dehydration at temperatures
of 60 °C or higher. Allow the bea-
ker and its contents to heat for 15
to 20 minutes until all reaction
has stopped. Add enough H2O2 to
give a 10% solution.
c. Transfer the suspension to 150-mL
centrifuge tubes, filling the tubes to
distribute their weight evenly, and
centrifuge the samples at 2200 rpm
for 10 minutes. Decant and dis-
card the supernatant liquid. If clay
is still suspended, add 2 to 3
drops of 1 N MgCI2, mix the super-
natant liquid, recentrifuge and de-
cant the supernatant liquor.
17.10.4 Preparation and
Treatment of Oriented
Slides from the
<0.002-mm Fraction of
Samples for Identification
of Clay Minerals (modified
from USDA/SCS, 1984)
1. Prepare two syringes by placing a
small circle of 80-mesh screen at the
bottom of each. Fill each syringe
with 3 cm3 of exchange resin. Charge
the exchange resin in one syringe with
Mg2+ by drawing 2 mL of 1.0 N MgCI2
solution into the syringe. Charge the
resin in the second syringe with K+ by
using a 1.0 N KCI by solution. Allow
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Page 8 of 12
the exchange resin in each syringe to
equilibrate for 10 minutes. Expel the
used solution from each syringe and
allow the syringe to stand for 10 min-
utes. Wash the exchange resin in
each syringe three times with 5 to 8
mL DDI water to flush out the excess
salt solutions.
After treating each 10 samples, re-
charge the resin in the same manner.
2. For each soil sample, clean four 32-
mm circular glass slides with ethanol.
This ensures good sample adhesion
to the glass slide. Also, label the
slides with the appropriate batch and
sample numbers.
3. Prepare a desiccator for storage of
the air-dried slides.
4. Using the syringe containing the Mg2+-
charged resin, withdraw 1 mL of the
<0.002-mm suspension obtained in
Section 17.10.3., step 6. Onto two
clean 32-mm circular glass slides,
slowly expel enough of the suspen-
sion to cover each slide. Allow the
slides to air dry at room temperature,
i.e., 22 °C. Use one slide for analysis
and archive the other slide. Record
the sample number of each pair of
slides and record the treatment as
"Mg-sat. AD" in the laboratory note-
book. Since the slides will be ana-
lyzed in successive order, maintain
the samples in sequence. X-Ray each
sample from 2° to 30° 20. Store the
patterns digitally for later printing.
NOTE: Do not set the XRD sample stage to
rotate or oscillate when analyzing
oriented slides.
5. Heat a desiccator containing 2 to 3
cm of ethylene glycol in a convection
oven at 70 °C. Place one Mg-sat. AD
slide from step 4 in the preheated
desiccator and allow the slide to
equilibrate for 1 hour. Note the sam-
ple number and the treatment as "Mg
sat.gly" in the laboratory notebook. X-
Ray the slide from 2° to 30° 20 imme-
diately after removal from the des-
iccator. Store the patterns digitally for
later printing.
6. Using the syringe containing the K+-
charged resin, withdraw 1 mL of the
<0.002-mm suspension obtained
in Section 17.10.3, step 6. Onto two
clean 32-mm circular glass slides,
slowly expel enough of the suspension
to cover each slide. Allow the slides
to air dry at room temperature, i.e., 22
°C. Use one slide for analysis and
archive the other slide. Record the
sample number of each pair of slides
and record the treatment as "K-sat.
AD" in the laboratory notebook. X-Ray
each sample from 2° to 30° 20. Store
the pattern for later printing.
7. Place the K-sat. AD slide from step 6
in a cold furnace, then ramp the tem-
perature to 110 °C for 1 hour. Allow
the furnace to cool to room tempera-
ture slowly. Place the slide in a des-
iccator over silica gel desiccant prior
to analysis. Note the sample number
and the treatment as "K-sat. 110 °C"
in the laboratory notebook. X-Ray the
slide from 2° to 30° 29. Store the
pattern digitally for later printing.
8. Place the K-sat. 110 °C slide from
step 7 in a cold furnace, then ramp
the temperature to 350 °C for 1 hour.
Allow the furnace to cool to room
temperature slowly. Place the slide
in a desiccator over silica gel desic-
cant prior to analysis. Note the sam-
ple number and the treatment as "K-
sat. 350 °C" in the laboratory note-
book. X-Ray the slide from 2° to 30°
20. Store the pattern digitally for later
printing.
9. Place the K-sat. 350 °C slide from
step 8 in a cold furnace, then ramp
the temperature to 550 °C for 1 hour.
Allow the furnace to cool to room
temperature slowly. Place the slide
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Section 17
Revision 2
Date: 12/86
Page 9 of 12
in a desiccator over silica gel desic-
cant prior to analysis. Note the sam-
ple number and the treatment as "K-
sat. 550 °C" in the laboratory note-
book. X-Ray from 2° to 30° 20.
Store the pattern digitally for printing.
17.10.5 Preparation of Randomly
Oriented Powder Mounts
from the <0.002-mm
Fraction of Soil Samples
1. Freeze-dry the remaining suspension
of <0.002-mm material from Section
7.10.3, step 6. Weigh the freeze-dried
material. If there is less than 3.0 g,
repeat Section 17.10.3 until there is
more than 3.0 g of freeze-dried mate-
rial. Record the total sample weight
on DDRP Form 401 (see Appendix D).
2. Weigh 2.0 g of the <0.002-mm frac-
tion and add 0.4 g of corundum.
Mix well in a Wiggle Bug mixer for
approximately 20 to 30 seconds.
Because mixing will generate enough
heat to alter some clay minerals,
excessive time in the mixer should be
avoided.
3. Prepare a randomly oriented powder
mount from the mixed sample as
described in Section 17.10.1, step 4.
X-ray the sample from 2° to 65° 20
while the stage is set to rotate and
oscillate. Set the diffractometer to
integrate the area under each of the
three strongest peaks of each miner-
al. Store the pattern digitally for later
printing.
17.11 Calculations
17.11.1 Mineral Identification and
Quantification
Table 17-1, compiled from Brown and
Brindley (1980), provides general guidelines for
interpreting the X-Ray diffraction patterns and
the effect of the various treatments. The
analyst can find more detailed descriptions of
the principles of X-Ray diffraction in Klug and
Alexander (1974), of the characteristics of clay
minerals in Weaver (1973), and of the identifi-
cation of clay minerals in Brindley and Brown
(1980), Carroll (1970), Jackson (1969), and
Hutchison (1974). The final interpretation, how-
ever, must rely on the analyst's experience.
Index the peaks in angstrom units (A)
using Bragg's Law:
n X = 2 d sin 0
where:
n = whole integer, assumed = 1,
A = wavelength of Cu K01 radiation =
1.540500 A
d = interplanar atomic distances in
the crystal lattice,
0 = angle of X-ray incidence = angle
of diffraction.
Use the entries from the Powder Dif-
fraction Files (a data base of references dis-
tributed solely by the Joint Committee for
Powder Diffraction Standards [JCPDS, 1985/
86]) stored in the computer and the software
pattern library (see Section 17.8) to make the
initial and final identification of the minerals.
Differentiate the dioctahedral and trioctahedral
clay minerals. Store the identified mineral
phase data for final printing on DDRP Form
401 (see Appendix D).
Calculate the percentages of each
mineral in the two randomly oriented powder
mounts Sections 17.10.2 and 17.10.5 by using
the following equation (after Chung, 1974):
\k, A
\
(17-2)
where:
x, = weight fraction of component i,
kf = reference intensity ratio (determined
in Section 17.10.1), X,. = weight
percent of corundum standard
added (20 percent),
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Page 10 of 12
Table 17-1. Effect of Some Diagnostic Treatment* on Spacing of First Low Angle Reflection of Clay Minerals
(Compiled from Brown and Brlndley, 1980)
Mineral
Kaolinite
Dickite
Halloysite-7 A
Halloysite-10 A
Serpentine
Mica
Smectite, Mg, Ca
Smectite, Na
Vermiculite,
Mg, Ca
Vermiculite, Na
Chlorite
(magnesian)
Chlorite(irorvrich)
Swelling Chlorite
Palygorskite
Sepiolite
Air-
Dried*
7
7
7
11
7
10
15
12.5
14.5
12.5
14
14
14
10.5
12.2
Ethylene
Glycol"
7
7
7
10
7
10
17
17
14.5
14.5
14
14
16-17
10.5
12.2
Treatment
300-350 •&*
7
7
7
7
7
10
10
10
10
10
14
14
14
10.5+9.2
12.2+10.4
500-600 -C"
Disappears
Disappears
Disappears
Disappears
Disappears
10
10
10
10
10
14
14
14
9.2
10.4
Temperature at
which Reflection
Disappears"
500-550 'C
550-650 'C
450-520 "C
450-520 "C
575-700 "C
800-1000 °C+
700-1000 -C
700-1000 -C
700-100 "C
700-1000 -C
800 -C
600 -C
700 -C
700 "C
Remarks
Occasionally we.ak broad
band at 12-14 A at 500-
550 'C.
Usqally broad reflection C.
14 A at 550-700 "C.
Dehydrates, .usually
irreversibly to 7 A form at
50-100 -C.
Broad reflection 11-14 A
region at 550650 °C; forms
divine and enstatite at 650-
700 -C.
Trioctahedral varieties more
stable in 700-1000 -C range.
Trioctahedral varieties more
stable in 700-1000 °C range.
14 A intensity increased
at 500-600 *C; forms olivine
at about 800 -C.
14 A intensity increased
at 500-600 -C; forms olivine
at about 600-700 *C.
Marked increase in 10.5 A
intensity at 150 *C.
0 Values are approximate in angstroms (A).
Temperature at which thermal changes occur is affected by size of crystals and duration of heating; larger crystals
require higher temperature and longer time for reaction.
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Page 11 of 12
I, = intensity of X-rays diffracted by a
selected plane (hkl) of component
i expressed as area under the peak
(Sections 17.10.2 or 17.10.5),
Ic = intensity of X-rays diffracted by a
selected plane (hkl) of the corun-
dum standard expressed as area
under the peak (Sections 17.10.2
or 17.10.5).
Record the percentage of each identi-
fied mineral on DDRP Form 401.
17.12 Precision and Accuracy
Because this semiquantitative method is
relatively new, the actual precision is unknown.
It is dependent upon both instrument and
sample and must be calculated from the data.
The precision of this method is estimated to
be within 10 percent relative for minerals with
low crystallinity in concentrations >50 percent.
For minerals with low crystallinity in concen-
trations less than 50 percent, the precision is
estimated to be within 50 percent relative
(personal communication, Dr. Mike Holland,
Terra Tek Core Services, Salt Lake City, Utah).
Precision is directly dependent upon crystallini-
ty: the higher the crystallinity of the mineral,
the greater the precision. Using highly crystal-
line minerals, Chung (1974) was able to attain
a precision of <1.0 percent between experi-
mental and known mineral contents.
The accuracy of XRD is based on a
statistical comparison of the intensity of
diffracted X-Rays to the background radiation
intensity. According to Klug and Alexander
(1974), uncertainty in the net peak height
strongly affects the absolute standard devia-
tion of the peak height to background ratio
when the background counting rate is appre-
ciable. When background is low, the net
percent standard deviation in the area under
the peak (corrected for background) is 2.24
percent. Chung (1974) attained an accuracy of
1.7 percent.
17.13 References
Blume, L. J., M. L, Papp, K. A Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. Appendix
A In: Direct/Delayed Response Project
Southern Blue Ridge Province Fie Id Sam-
pling Report. Vol. J: Field Sampling.
U.S. Environmental Protection Agency,
Las Vegas, Nevada.
Brindley, G. W., and G. Brown. 1980. Crystal
Structures of Clay Minerals and Their X-
Ray Identification. Monograph No. 5.
Mineralogical Society, London, England.
Brown, G., and G. W. Brindley. 1980. X-Ray
Diffraction Procedures for Clay Mineral
Identification. In: Brindley, G. W., and
G. Brown, 1980. Crystal Structures of
Clay Minerals and their X-Ray Identifica-
tion. Monograph No. 5. Mineralogical
Society, London, England.
Carroll, D. 1970. Clay Minerals: A Guide to
Their Identification. Special Paper 126.
The Geological Society of America, Boul-
der, Colorado.
Chung, F. H. 1974. Quantitative Interpretation
of X-Ray Diffraction Patterns of Mixtures.
I. Matrix-Flushing Method for Quantita-
tive Multicomponent Analysis. J. Applied
Crystallogr. v. 7, pp. 519-525.
Hutchison, C. S. 1974. Laboratory Handbook
of Petrographic Techniques. John Wiley
and Sons, New York, New York.
Jackson, M. L. 1969. Soil Chemical Analysis -
Advanced Course, 2nd Ed. Published by
the author, Department of Soil Science,
University of Wisconsin, Madison, Wis-
consin.
Joint Committee for Powder Diffraction Stan-
dards. 1985/86. Powder Diffraction Files.
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Section 17
Revision 2
Date: 12/86
Page 12 of 12
International Centre for Diffraction Data,
Swarthmore, Pennsylvania.
Klug, H. P., and L E. Alexander. 1974. X-Ray
Diffraction Procedures. John Wiley and
Sons, New York, New York.
Muller, G. 1967. Methods in Sedimentary
Petrology. E. Schweizerbart'sche
Verlagsbuchhandlung/Hafner, New York.
National Bureau of Standards. 1971. Standard
X-Ray Diffraction Powder Patterns.
Monograph 25. p. 3. U.S. Department of
Commerce, Gaithersburg, Maryland.
United States Department of Agriculture/Soil
Conservation Service. 1984. Soil Survey
Laboratory Methods and Procedures for
Collecting Soil Samples. Soil Survey
Investigations Report No. 1, USDA. U.S.
Government Printing Office, Washington,
D.C.
Weaver, C. E. 1973. The Chemistry of Clay
Minerals. Developments in Sedimento-
logy 15. Elsevier Scientific, New York,
New York.
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Section 18
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Page 1 of 4
18 Wavelength-Dispersive X-Ray Fluorescence Spectrometry
18.1 Scope and Application
This method determines the elemental
composition of the minerals in the <2-mm size
fraction. These data are used to refine the
semiquantitative data from the X-ray powder
diffraction analysis (see Section 17) for the
percentage of minerals in each soil sample.
18.2 Summary of Method
Bulk soil samples are pressed into pel-
lets and are analyzed by wavelength-dispersive
X-ray fluorescence (XRF) spectrometry.
Twenty-five fixed channels are fitted to an
instrument like the Phillips PW 1600 XRF unit
to provide simultaneous analysis of twenty-five
elements.
18.3 Interferences
Background signals are predicted and
subtracted by commercially available software
packages. The background signal is obtained
by analyzing standards of pure element oxides,
salts, and mixtures of oxides and salts and by
measuring the continuum for other elements
not present in the standards. Thirty standards
are analyzed, and the resulting background
signals are averaged to arrive at at final back-
ground signal value. For each fixed channel,
the background signal depends on the average
atomic number of the sample; the elements in
the sample range in atomic number from 10 to
25.
This interval accurately represents the
range in atomic number expected in naturally
occurring samples such as soils, rocks, and
marine sediments. The measured background
signals (Bp^J for the fixed channel are related
to measurements of the scattered continuum
(Boon,) obtained at one of several 20 angles;
where:
Plots of k versus B^, permit calculation
of k if B^ is known. For routine sample
measurements, B^, is measured and the
software calculates k for each fixed channel.
The background is automatically subtracted
since B = k B.
Spectral interferences are minimized
through the inherently high resolution of the
wavelength-dispersive XRF; however, some
peak overlaps are observed. For each overlap
situation, preparation of a series of standards
containing a fixed concentration of analyte and
a varying concentration of the interfering
element are prepared in order to characterize
the contribution of the interfering element to
the measured analyte signal. The appropriate
functional relationships are developed to
permit software to predict and subtract the
contribution of an interfering element to the
measured analyte signal.
Interelement effects are resolved by
means of commercially available software
packages, e.g., the software package devel-
oped by Criss Software Inc. Criss's XRFIIF
software is used to convert measured X-ray
fluorescence line intensities to chemical com-
position. XRFIIF employs measured net inten-
sities from standards to establish a set of
theoretical and empirical coefficients that fit
the concentration versus intensity relationships
over the range of compositions represented by
the standards.
18.4 Safety
Follow standard laboratory safety prac-
tices and wear a laboratory coat, gloves, and
safety glasses when preparing and handling
reagents. Many metal salts are extremely toxic
and may be fatal if swallowed. Wash hands
thoroughly after handling metal salts. x
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Page 2 of 4
Follow the safety precautions of the
manufacturer when operating instruments.
Personnel working with the X-ray diffract-
ometer must wear individual radiation badges.
Check radiation badges on a monthly basis to
assess exposure. In addition, on a monthly
basis, use a detector to check for radiation
leaks from the instrument.
18.5 Apparatus and Equipment
• Simultaneous wavelength-dispersive X-
ray fluorescence spectrometer, Philips
PW 1600 or equivalent.
• Hydraulic press, capable of producing
pressure of 5 tons per square inch.
• Pellet die.
• Analytical balance.
• Desiccator.
18.6 Reagents and Consumable
Materials
• Calibration Standards-Certified stan-
dards for the calibration of the EDXRF
unit:
SY-3 CCRMP (Canadian
Certified Reference
Materials Project)
MRS-1 CCRMP
MAG-1 USGS (U.S. Geological
Survey)
NOD A-1 USGS
BCR-3 USGS
GSP-1 USGS
RGM-1 USGS
SDC-1 USGS
PCC-1 USGS
DTS-1 USGS
SRM 97a NBS (National Bureau
of Standards)
SRM 278 NBS
SRM 688 NBS
SRM 1649 NBS
• Microcellulose powder.
• Desiccant.
18.7 Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation
laboratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
Once the mineralogical samples are aliquoted,
the mineralogical samples do not need to be
refrigerated. In the mineralogical laboratory,
all samples are kept sealed when not being
used.
All pelletized samples must be kept in a
desiccator when not being analyzed.
18.8 Calibration and
Standardization
Follow the instructions of the manufac-
turer for calibration of the instrument. Gener-
ally, a suite of at least 25 certified standard
rock and sediment samples are analyzed by
the XRF using the same measurement parame-
ters as are used for actual samples. Blank
signals are subtracted, and signals are cor-
rected for spectral interferences as described
in Section 18.3. The operational software is
then used to establish data files which contain
the calibration information required to convert
the measured net intensities of actual samples
to elemental concentrations. Calibration using
Criss software requires inputting the known
elemental concentrations for the standards
and their measured net intensities. Criss
software allows the measured intensities for
the standards to be scaled in any appropriate
manner as long as the scaling is consistently
applied. To ensure that the calibration is not
affected by differences in instrument response
which are due to factors such as replacement
of a detector, changing of a tank of detector
gas, or long term drift, all net element signals
of samples and standards are divided by the
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Page 3 of 4
corresponding net element signal of the moni-
tor standard; therefore, the instrument is
calibrated in terms of signal ratios. The moni-
tor standard is measured several times during
the analysis of each suite of samples, and the
same monitor standard is used for all samples
and standard runs.
18.9 Quality Control
The quality control calibration sample or
monitor standard is composed of a mixture of
standard reference materials to obtain a
standard containing all analytes in approxi-
mately the mid-concentration range for sam-
ples under study. The following mixture is
suggested:
SY-3 (CCRMP) 41.29%
MAG-1 (USGS) 42.75%
SRM 1649 (NBS) 1.34%
NOD A-1 (USGS) 14.63%
total
100.01%
7.2899 g
7.5473 g
0.2360 g
2.5825 o
17.6557 g
To determine the result for each analyte,
signal ratios are calculated between the moni-
tor standard and the calibration standards and
between the monitor standard and each sam-
ple. This minimizes the effect of instrumental
variability.
If the carousel does not accommodate a
full batch of 26 samples, analyze half-batch
lots, i.e., 13 samples. In addition, include the
monitor standard and a blank. The monitor
standard is measured several times during the
analysis of each group of samples. The
monitor standard is analyzed as an actual
sample so that its measured concentration
can be checked after each set of samples has
been analyzed. The blank is a pellet made of
micro-cellulose only. Perform a duplicate
analysts on a separate portion of each thir-
teenth routine sample or on one sample from
each analytical run.
18.10 Procedure
18.10.1 Sample Preparation
1. Homogenize the <2-mm soil sample
pulverized in Section 17.10.2, step 2, by
passing it through a Jones-type riffle-
splitter seven times.
2. Weigh 0.5 g soil sample and 2.0 g
microcellulose powder. Mix sample,
then place it into the 32-mm diameter
pellet die. Do not mix the sample with
the microcellulose; the microcellulose
forms a supporting substrate that is
not exposed directly to the X-rays.
Assemble die and place it on hydraulic
press at 5 tons pressure per square
inch to form the pellet. Store the
pellets in a desiccator when the
pellets are not undergoing analysis.
3. The instrument is completely auto-
mated; therefore, load the sample
carousel and log the samples into the
analysis program. Place samples so
that the monitor samples bracket the
actual samples.
18.10.2 Instrumental
Requirements
The instrumental detection limit must be
established for each element. The concentra-
tion at the detection limit CL as defined by
Birks (1969, p. 54) is used: the amount of
analyte which gives a net line intensity equal
to three times the square root of the back-
ground intensity for a specified counting time.
The optimum combination of operating
conditions is shown in Table 18-1.
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Section 18
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Page 4 of 4
Table 18-1. Optimum Combination of Operational
Conditions* (Philips Electronic
Instruments, 1982)
Item
Parameter
Exciting radiation Rh
Kilovolts 50
Milliamperes 50
Detector
Measurement time 120 seconds
gas flow proportional
counters for atomic
numbers 11 to 19
sealed Xe counters for
atomic numbers > 22
sealed Kr detectors for
Ti and Ca
'Detector power supplies and pulse height analyzers are
set according to the manufacturer's instructions.
18.11 Calculations
Raw data files are generated by the
software that operates the XRF unit. Net
intensity data files are generated, and final
elemental concentrations are provided by
XRFIIF software or equipment. All spectral
data must be recorded and printed out to be
included in the data package. Each sample
printout must be labeled with the sample
number, date of analysis, instrument detection
limits, reference standard maximum intensity,
concentration of element in percent or ppm,
and concentration of oxide in percent or ppm.
18.12 Precision and Accuracy
Precision is defined (Jenkins et al., 1981)
as the degree of mutual agreement between
repeated individual measurements made on the
same sample. The precision of a well-
designed X-ray spectrometer is typically on the
order of one-tenth of a percent (Jenkins, 1984).
Accuracy is defined (Jenkins et al., 1981)
as the degree of agreement between a meas-
urement made on a reference standard and
the "true result' for an accepted reference
standard. In quantitative terms, this corre-
sponds to approximately 0.1 percent absolute
(Jenkins, 1984).
18.13 References
Blume, L J., M. L Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed
Response Project Soil Survey. Appendix
A In: Direct/Delayed Response Project
Southern Blue Ridge Province Field Sam-
pling Report. Vol. I: Field Sampling.
U.S. Environmental Protection Agency,
Las Vegas, Nevada.
Jenkins, R., R. W. Gould, and D. Gedcke. 1981.
Quantitative X-RaySpectrometry. Marcel-
Dekker, New York, New York.
Jenkins, R. 1984. X-Ray Fluorescence Analy-
sis. Anal. Chem., v. 56, n 9, pp. 1099-
1106.
Philips Electronic Instruments, Inc. 1982.
Operations Manual for Philips PW-1600
XRF. Philips Electronic Instruments,
Mahwah, New Jersey.
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Section 19
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Page 1 of 5
19 Scanning Electron Microscopy with Energy-
Dispersive X-Ray Fluorescence Analysis
19.1 Scope and Application
Pictures obtained from scanning electron
microscopy (SEM) will provide information
about crystal morphology, such as form, habit,
and possibly crystal system, the type of
weathering, i.e., chemical or physical, and the
degree of weathering. The quantitative energy
dispersive X-ray fluorescence (EDXRF) analysis
of individual mineral grains will provide micro-
chemical compositions of the specific mineral
grains analyzed.
19.2 Summary of Method
The heavy minerals and light minerals of
the very fine sand fraction, i.e., 0.105- mm to
0.053-mm fraction, are separated gravimetrical-
ly by a heavy liquid separation using sodium
polytungstate (density = 2.95). The clay-sized
fraction is separated gravimetrically from the
soil samples (see Section 17.10.3) and is
freeze-dried (see Section 17.10.5). A three- to
five- milligram aliquot of each fraction is
mounted on doublesided tape for examination
by SEM and analysis by EDXRF.
The SEM electron beam excites with
known secondary energies (fluorescence) and
produces measurable data that are directly
dependent on elemental concentrations and
that are mathematically convertable into ele-
mental concentrations. Peak intensities are
determined by one or more of three methods:
(1) simple integration of the area under the
peaks, (2) spectral peak-fitting to stored
reference peaks, and (3) Gaussian deconvolu-
tion by means of a program such as one
developed by the Kevex Corporation.
19.3 Interferences
Spectral interferences, interelemental
interferences, and background corrections are
automatically calculated by the Kevex Corpora-
tion or equivalent software.
19.4 Safety
Follow standard laboratory safety prac-
tices and wear a laboratory coat, gloves, and
safety glasses when preparing and handling
reagents. Many metal salts are extremely
toxic and may be fatal if swallowed. Wash
hands thoroughly after handling metal salts.
Follow the safety precautions of the
manufacturer when operating instruments.
Personnel working with the X-ray diffract-
ometer must wear individual radiation badges.
Check radiation badges on a monthly basis to
assess exposure. In addition, on a monthly
basis, use a detector to check for radiation
leaks from the instrument.
19.5 Apparatus and Equipment
• Scanning electron microscope (SEM),
with 200- to 300-angstrom resolution
in the secondary electron mode.
• Gold-palladium sputter-coater, with an
argon diffusion chamber.
• Energy-dispersive X-ray fluorescence
(EDXRF) analytical unit and software,
Kevex or equivalent, which can inter-
face with the SEM.
• Separatory funnel, 250 ml_.
• Fritted funnel, 50 ml.
• Sieves, 60-mesh and 270-mesh.
• Polaroid camera.
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Section 19
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Page 2 of 5
19.6 Reagents and Consumable
Materials
• Gold-palladium wire, metal for coating
the specimen.
• Film, 35-mm or 4x5-inch format.
• Film, Polaroid type 55.
• Certified microprobe mineral and rock
standards-available from Tousimis
Company, Rockville, Maryland.
• Sodium polytungstate, density = 2.95,
reagent grade.
• Filter paper, Whatman No. 1.
• Double-deionized water (DDI H2O) or
equivalent.
• Double-sided cellophane tape.
• Silver conducting paint.
19.7 Sample Collection,
Preservation, and Storage
Sample collection is discussed in Blume
et al. (1987). No preservatives are added to
the samples. Within 24 hours of collection,
samples are delivered to the preparation
laboratory and are refrigerated at 4 °C. If this
time requirement cannot be met, the samples
are placed in a cooler after they are collected.
Once the mineralogical samples are aliquoted,
the mineralogical samples do not need to be
refrigerated. In the mineralogical laboratory,
all samples are kept sealed when not being
used.
Each prepared sample must be kept in a
desiccator when not undergoing analysis.
19.8 Calibration and
Standardization
Follow the calibration procedure supplied
by the instrument manufacturer.
Prior to sample analysis by EDXRF, use
pure Al and Cu standards to check the peak-
to- peak spacings and peak position of each
channel. Store the spectra at the laboratory
for audit purposes.
Build a library of reference spectra by
collecting three spectra from each certified
reference standard. Keep a copy of each
spectrum for audit purposes.
Analyze the reference standard three
times by EDXRF and compare the results
against those from the previous EDXRF analy-
sis. If the change in peak height is greater
than 10 percent, recalibrate the instrument with
the reference standards.
19.9 Quality Control
The SEM must be serviced within the
month prior to the start of analysis. Retain a
copy of the service report for audit purposes.
Perform a duplicate EDXRF analysis on
a separate portion of every fifteenth sample.
Each batch of 15 samples and the duplicate
must be prepared by the same technician.
The detection limit is defined by operat-
ing conditions such as specimen/ beam/
detector geometry, excitation voltage, and
acquisition time. The slope of the line relating
X-ray intensity in counts to elemental concen-
tration is expressed algebraically as follows:
Y = mX + b
The change in the Y axis is equal to the
counts per second per percent elemental
concentration (mX) added to the point at which
the line intersects the Y axis (b). From this
simple formula, the relationship that predicts
the mean detection limit for an element within
a specific specimen matrix is derived.
Mean Detection Limit = 3/m
where:
I background
/counts/second
' time
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3 = standard deviations from back-
ground level (approximately equiva-
lent to a one percent significance
level);
m = counts per second per percent
elemental concentration;
background counts
per second = counts per second seen in
the background under the
peak representing the ele-
ment;
time = seconds during which the data are
acquired.
The factors in the equation include a
sensitivity factor, i.e., 3/m, which addresses
the statistical significance of the peak and the
intensity vs. concentration relationship, and a
background factor, i.e., the square root of the
background intensity over time, which esti-
mates the noise level or interference present in
the analysis. The sensitivity factor gives the
slope of the line relation (intensity and concen-
tration); the background factor represents the
intercept of the line and gives the detection
limit for the element within the specific matrix
To be detected, an element must emit enough
characteristic radiation to cause a peak that is
statistically significant above background (from
Alfred Soeldner, 1986, unpublished manuscript).
New film must be used. All film must
be refrigerated when not in use. Allow the
refrigerated film time to equilibrate to room
temperature before use.
Daily, take two high resolution pic-
tures at 30,000x magnification of the sample
undergoing analysis, one picture at the begin-
ning of the analyses and one at the end.
These pictures are a record indicating that the
resolution of the instrument has been main-
tained. Keep the pictures on file at the labora-
tory for audit purposes.
Collect two spectra per day from the
same spot on a reference standard; the refer-
ence standard contains as many elements as
possible. Collect one spectra at the beginning
of the analyses and one at the end of the
analyses. For each required element, include
a verification printout of all the collected spec-
tra for calibration. Record pertinent geometry
and instrument settings daily on DDRP Form
403 (see Appendix D).
19.10 Procedure
1. Separate up to 5 g of the 0.105-mm to
0.053-mm fraction by wet sieving. Dry
this fraction at 105 °C.
2. Transfer the dried 0.105-mm to 0.053-
mm fraction to a 250-mL separatory
funnel containing 200 ml_ sodium
polytungstate (SPT) with a density of
2.95. The minerals separate gravimet-
rically according to their densities.
Those minerals with densities <2.95
are referred to as "light minerals," and
minerals with densities >2.95 are
referred to as "heavy minerals." As the
separation takes place, occasionally
stir the light portion with a spatula to
disperse air bubbles and to free some
of the heavier minerals from possible
aggregation.
3. After the separation is complete, open
the stopcock of the separatory funnel
and allow the heavy mineral portion to
flow into a beaker. Pour the contents
of this beaker (SPT + heavy minerals)
into a fritted funnel lined with filter
paper and seated on a vacuum flask.
Turn on the vacuum, and filter the SPT
through the heavy fraction. After the
SPT has filtered through the minerals,
move the funnel containing the heavy
minerals to a second vacuum flask.
Wash the heavy minerals with DDI
H2O until they are free of SPT. Tap
the side of the fritted funnel. When
the grains fall apart from one another,
they are free of SPT.
NOTE: The SPT in the first flask is clean and
reusable and has the original density.
4. Allow the light mineral portion still in
the separatory funnel to flow into a
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beaker. Pour the contents of this
beaker into a fritted funnel lined with
filter paper and seated on a vacuum
flask. Vacuum filter the SPT from the
solids, and wash the light mineral
portion in the same manner as the
heavy mineral portion. Transfer the
heavy and light fractions to clean,
preweighed containers labeled "Heavy
Minerals" and "Light Minerals,"
respectively.
5. Prepare samples by placing 3 mg of
the light mineral fraction on a slide
covered with doubled-sided tape.
Repeat this preparation for the heavy
and the clay fractions. Use the clay
fraction (<0.002 mm) produced by the
procedure described in Section 17.10.3,
step 6, and freeze-dried as described
in Section 17.10.5.
6. Place the slide in the sputter-coater,
seal the argon diffusion chamber,
evacuate the chamber, bleed in argon,
and coat the slide with gold-palladi-
um. After the slide is coated, equalize
the chamber, remove the slide, and
check the coating for electrical conti-
nuity. If necessary, use silver con-
ducting paint to complete the continu-
ity. The slide is ready for analysis.
7. Place the slide on the stage of the
SEM. Connect the ground wire to the
slide. Use silver-conducting paint if
the connection is weak. Seal the
stage in the chamber and evacuate
the chamber. Raise the stage to the
proper height for coarse focus of the
electron beam. Turn on the beam and
adjust beam current for proper focus.
8. Conduct a survey scan of the sample
at a magnification of 50x to S.OOOx.
During the scanning of the sample,
have a second analyst record obser-
vations concerning areas photo-
graphed and particles analyzed by
EDXRF. The analyst must record ob-
servations in a laboratory notebook or
on a Dictaphone and must be experi-
enced in geological specimen micro-
analysis and interpretation. Record
this commentary on DDRP Form 404
(see Appendix D).
All photographs must include the magni-
fication, a scale, and the name of the object
photographed. After an EDXRF analysis is
completed and the area of the specimen is
photographed, the area analyzed must be
labeled on the photograph. Record the data
on DDRP Form 405 (see Appendix D). The
EDXRF spectra must be attached to the form.
19.11 Calculations
The EDXRF software automatically
counts and corrects for background, spectral,
and interelemental interferences (see Berlin,
1978; Jenkins et al, 1981; Jenkins, 1984;
Lakowicz, 1983; and MOller, 1972).
19.12 Precision and Accuracy
The precision of current X-ray spectrome-
ters is typically on the order of 0.1 percent
(Jenkins, 1984).
For this type of analysis, the accuracy is
estimated at 10 percent (personal communica-
tion, Alfred Soeldner, Oregon State University).
19.13 References
Bertin, E. P. 1978. Introduction toX-RaySpec-
trometric Analysis. Plenum Press, New
York, New York.
Blume, L J.. M. L Papp, K. A. Cappo, J. K.
Bartz, and D. S. Coffey. 1987. Soil Sam-
pling Manual for the Direct/Delayed Re-
sponse Project Soil Survey. Appendix A
In: Direct/Delayed Response Project
Southern Blue Ridge Province Field Sam-
pling Report: Vol. I: Field Sampling.
U.S. Environmental Protection Agency,
Las Vegas, Nevada.
Jenkins, R., R. W. Gould, and D. Gedcke. 1981.
Quantitative X-Ray Spectrometry. Mar-
cel-Dekker, New York, New York.
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Page 5 of 5
Jenkins, R. 1984. X-Ray Fluorescence Analy-
sis. Anal. Chem.. v. 56, n. 9, pp. 1099-
1106.
Lakowicz, J. R. 1983. Principles of Fluores-
cence Spectroscopy. Plenum Press, New
York, New York.
Muller, R. O. 1972. Spectrochemical Analysis
by X-Ray Fluorescence. Plenum Press,
New York, New York.
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Appendix A
Atomic Absorption Spectroscopy Methods
1 Scope and Application
1.1 Metals in solution may be readily determined by atomic absorption Spectroscopy. The
method is simple, rapid, and applicable to a large number of metals in drinking, surface, and
saline waters, and domestic and industrial wastes. While drinking waters free of participate
matter may be analyzed directly, domestic and industrial wastes require processing to
solubilize suspended material. Sludges, sediments, and other solid type samples may also
be analyzed after proper pretreatment.
1.2 Detection limits, sensitivity, and optimum ranges of the metals will vary with the various
makes and models of satisfactory atomic absorption spectrophotometers. The data shown
in Table A-1, however, provide some indication of the actual concentration ranges
measurable by direct aspiration and by using furnace techniques. In the majority of
instances, the concentration range shown in the table by direct aspiration may be extended
much lower with scale expansion and conversely extended upwards by using a less sensitive
wavelength or by rotating the burner head. Detection limits by direct aspiration may also
be extended through concentration of the sample through solvent extraction techniques.
Lower concentrations may also be determined using the furnace techniques, or both. The
concentration ranges given in Table A-1 are somewhat dependent on equipment such as the
type of spectrophotometer and furnace accessory, the energy source, and the degree of
electrical expansion of the output signal. When using furnace techniques, however, the
analyst should be cautioned as to possible chemical reactions occurring at elevated
temperatures which may result in either suppression or enhancement of the analysis
element. To insure valid data with furnace techniques, the analyst must examine each
matrix for interference effects (see 5.2.1) and if detected, must treat the matrix accordingly
by using either successive dilution, matrix modification, or the method of standard additions
(see 8.5).
1.3 Where direct aspiration atomic absorption techniques do not provide adequate sensitivity,
in addition to the furnace procedure, reference is made to specialized procedures such as
the gaseous hydride method for arsenic and selenium, the cold vapor technique for mercury,
and the chelation-extraction procedure for selected metals. Reference to approved
colorimetric methods is also made.
1.4 Atomic absorption procedures are provided as the methods of choice; however, other
instrumental methods have also been shown to be capable of producing precise and
accurate analytical data. These instrumental techniques include emission Spectroscopy,
X-ray fluorescence, spark source mass Spectroscopy, and anodic stripping to name but a
few. The analyst should be cautioned that these methods are highly specialized techniques
requiring a high degree of skill to interpret results and to obtain valid data. These above
mentioned techniques are presently considered as alternate test procedures, and approval
must be obtained prior to their use.
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Table A-1. Atomic Absorption Concentration Rang**'
Direct Aspiration
Metal*
Aluminum
Antimony
Arsenic*
Barium(p)
Beryllium
Cadmium
Calcium
Chromium
Cobalt
Copper
Gold
Iridium(p)
Iron
Lead
Magnesium
Manganese
Mercury'
Molybdenum(p)
Nickel(p)
Osmium
Palladium(p)
Platinum(p)
Potassium
Rhenium(p)
Rhodium(p)
Ruthenium
Selenium8
Silver
Sodium
Thallium
Tin
Titanium(p)
Vanadium(p)
Zinc
Detection
Limit
(mg/L)
0.1
0.2
0.002
0.1
0.005
0.005
0.01
0.05
0.05
0.02
0.1
3
0.03
0.1
0.001
0.01
0.0002
0.1
0.04
0.3
0.1
0.2
0.01
5
0.05
0.2
0.002
0.01
0.002
0.1
0.8
0.4
0.2
0.005
* The concentrations shown are not
absorption spectrophotometer.
For furnace
Optimum
Sensi- Concentration
tivity
(mg/L)
1
0.5
_
0.4
0.025
0.025
0.08
0.25
0.2
0.1
0.25
8
0.12
0.5
0.007
0.05
_.
0.4
0.15
1
0.25
2
0.04
15
0.3
0.5
—
0.06
0.015
0.5
4
2
0.8
0.02
Range
(mg/L)
5-50
1-40
0.002-0.02
1-20
0.05-2
0.05-2
0.2-7
0.5-10
0.5-5
0.2-5
0.5-20
20-500
0.3-5
1-20
0.02-0.5
0.1-3
0.0002
1-40
0.3-5
2-100
0.5-15
5-75
0.1-2
50-1000
1-30
1-50
0.002-0.02
0.1-4
0.03-1
1-20
10-300
5-100
2-100
0.05-1
Furnace
Detection
Limit
(M9/L)
3
3
1
2
0.2
0.1
1
1
1
1
30
1
1
0.2
0.01
1
1
20
5
20
200
5
20
2
0.2
1
5
10
4
0.05
contrived values and should be obtainable with any
sensitivity values consult instrument operating
c The listed furnace values are those expected when using a
case of arsenic and selenium where gas interrupt is used.
The symbol
(p) indicates the use of
pyrolytic graphite with
manual.
Procedureftc
Optimum
Concentration
Range
<«>/L)
20-200
20-300
5-100
10-200
1-30
0.5-10
5-100
5-100
5-100
5-100
100-1500
5-100
5-100
1-30
3-60
5-50
50-500
20-400
100-2000
5005000
20-400
100-2000
5-100
1-25
5-100
20-300
50-500
10-200
0.2-4
satisfactory atomic
20 iA. injection and normal gas flow except in the
the furnace
* Gaseous hydride method.
Cold vapor
technique.
procedure.
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2 Summary of Method
2.1 In direct aspiration atomic absorption spectroscopy, a sample is aspirated and atomized
in a flame. A light beam from a hollow cathode lamp whose cathode is made of the
element to be determined is directed through the flame into a monochromator and onto a
detector that measures the amount of light absorbed. Absorption depends upon the
presence of free unexcited ground state atoms in the flame. Since the wavelength of the
light beam is characteristic of only the metal being determined, the light energy absorbed
by the flame is a measure of the concentration of that metal in the sample. This principle
is the basis of atomic absorption spectroscopy.
2.2 Although methods have been reported for the analysis of solids by atomic absorption
spectroscopy (Spectrochim Acta, 24B53,1969), the technique generally is limited to metals
in solution or solubilized through some form of sample processing.
2.2.1 Preliminary treatment of wastewater and industrial effluents is usually necessary
because of the complexity and variability of the sample matrix Suspended material
must be subjected to a solubilization process before analysis. This process may vary
because of the metals to be determined and the nature of the sample being analyzed.
When the breakdown of organic material is necessitated, the process should include
a wet digestion with nitric acid.
2.2.2 In those instances where complete characterization of a sample is desired, the
suspended material must be analyzed separately. This may be accomplished by filtration
and acid digestion of the suspended material. Metallic constituents in this acid digest
are subsequently determined, and the sum of the dissolved plus suspended concentra-
tions will then provide the total concentrations present. The sample should be filtered
as soon as possible after collection, and the filtrate should be acidified immediately.
2.2.3 The total sample may also be treated with acid without prior filtration to measure what
may be termed "total recoverable" concentrations.
2.3 When using the furnace technique in conjunction with an atomic absorption spectrophotome-
ter, a representative aliquot of a sample is placed in the graphite tube in the furnace,
evaporated to dryness, charred, and atomized. As a greater percentage of available analyte
atoms are vaporized and dissociated for absorption in the tube than the flame, the use of
small sample volumes or detection of low concentrations of elements is possible. The
principle is essentially the same as with direct aspiration atomic absorption except a
furnace, rather than a flame, is used to atomize the sample. Radiation from a given excited
element is passed through the vapor containing ground state atoms of that element. The
intensity of the transmitted radiation decreases in proportion to the amount of the ground
state element in the vapor. The metal atoms to be measured are placed in the beam of
radiation by increasing the temperature of the furnace which causes the injected specimen
to be volatilized. A monochromator isolates the characteristic radiation from the hollow
cathode lamp, and a photosensitive device measures the attenuated transmitted radiation.
3 Definition of Terms
3.1 Optimum Concentration Range-A range, defined by limits expressed in concentration, below
which scale expansion must be used and above which curve correction should be
considered. This range will vary with the sensitivity of the instrument and with the operating
condition employed.
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3.2 Sensitivity-The concentration in milligrams of metal per liter that produces an absorption
of 1%.
3.3 Detection Limit-Detection limits can be expressed as either an instrumental or method
parameter. The limiting factor of the former using acid water standards would be the
signal to noise ratio and degree of scale expansion used, while the latter would be more
affected by the sample matrix and preparation procedure used. The Scientific Apparatus
Makers Association (SAMA) has approved the following definition for detection limit: that
concentration of an element which would yield an absorbance equal to twice the standard
deviation of a series of measurements of a solution, the concentration of which is distinctly
detectable above but close to blank absorbance measurement. The detection limit values
listed in Table A-1 and on the individual analysis sheets are to be considered minimum
working limits achievable with the procedures given in this manual. These values may differ
from the optimum detection limit reported by the various instrument manufacturers.
3.4 Dissolved Metals-Those constituents (metals) which will pass through a 0.45 p membrane
filter.
3.5 Suspended Metals-Those constituents (metals) which are retained by a 0.45 ju membrane
filter.
3.6 Total Metals-The concentration of metals determined on an unfiltered sample following
vigorous digestion (Section 4.1.3), or the sum of the concentrations of metals determined
in both the dissolved and suspended fractions.
3.7 Total Recoverable Metals-The concentration of metals in an unfiltered sample following
treatment with hot dilute mineral acid (Section 4.1.4).
4 Sample Handling and Preservation
4.1 For the determination of trace metals, contamination and loss are of prime concern. Dust
in the laboratory environment, impurities in reagents, and impurities on laboratory apparatus
which the sample contacts are all sources of potential contamination. For liquid samples,
containers can introduce either positive or negative errors in the measurement of trace
metals by (a) contributing contaminants through leaching or surface desorption and by (b)
depleting concentrations through absorption. Thus the collection and treatment of the
sample prior to analysis requires particular attention. The sample bottle whether
borosilicate glass, polyethylene, polypropylene or Teflon should be thoroughly washed with
detergent and tap water, should be rinsed with 1:1 nitric acid, tap water, 1:1 hydrochloric
acid, tap water, and finally deionized distilled water in that order.
NOTE 1: Chromic acid may be useful to remove organic deposits from glassware; however, the
analyst should be cautioned that the glassware must be thoroughly rinsed with water to
remove the last traces of chromium. This is especially important if chromium is to be
included in the analytical scheme. A commercial product-NOCHROMIX-available from
Godax Laboratories, 6 Varick St. New York, N.Y. 10013, may be used in place of chromic
acid. (Chromic acid should not be used with plastic bottles.)
NOTE 2: If it can be documented through an active analytical quality control program using spiked
samples, reagent and sample blanks that certain steps in the cleaning procedure are not
required for routine samples, those steps may be eliminated from the procedure. Before
collection of the sample, a decision must be made as to the type of data desired, i.e.,
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dissolved, suspended, total or total recoverable. For container preference, maximum
holding time, and sample preservation at time of collection, see Table 2 in the front part
of this manual. Drinking water samples containing suspended and settleable material
should be prepared by using the total recoverable metal procedure (section 4.1.4).
4.1.1 For the determination of dissolved constituents, the sample must be filtered through a
0.45 n membrane filter as soon as practical after collection. (Glass or plastic filtering
apparatus using plain, non-grid marked, membrane filters are recommended to avoid
possible contamination.) Use the first 50-100 ml to rinse the filter flask. Discard this
portion and collect the required volume of filtrate. Acidify the filtrate with 1:1 redistilled
HNO3 to a pH of <2. Normally, 3 mL of (1:1) acid per liter should be sufficient to
preserve the sample (See Note 3). If hexavalent chromium is to be included in the
analytical scheme, a portion of the filtrate should be transferred before acidification to
a separate container and should be analyzed as soon as possible by using Method
218.4. Analyses performed on a sample so treated shall be reported as "dissolved"
concentrations.
NOTE 3: If a precipitate is formed upon acidification, the filtrate should be digested by using 4.1.3.
Also, it has been suggested (International Biological Program, Symposium on Analytical
Methods, Amsterdam, Oct. 1966) that additional acid, as much as 25 mL of cone. HCI/liter,
may be required to stabilize certain types of highly buffered samples if they are to be
stored for any length of time. Therefore, special precautions should be observed for
preservation and storage of unusual samples intended for metal analysis.
4.1.2 For the determination of suspended metals a representative volume of unpreserved
sample must be filtered through a 0.45 n membrane filter. When considerable
suspended material is present, as little as 100 ml of a well mixed sample is filtered.
Record the volume filtered and transfer the membrane filter containing the insoluble
material to a 250 mL Griffin beaker and add 3 mL cone, redistilled HNO3. Cover the
beaker with a watch glass and heat gently. The warm acid will soon dissolve the
membrane. Increase the temperature of the hot plate and digest the material. When
the acid has nearly evaporated, cool the beaker and watch glass and add another 3 mL
of cone, redistilled HNO3. Cover and continue heating until the digestion is complete;
generally complete digestion is indicated by a light colored residue. Evaporate to near
dryness (DO NOT BAKE), add 5 mL distilled HCI (1:1), and warm the beaker gently to
dissolve any soluble material. (If the sample is to be analyzed by the furnace
procedure, 1 mL of 1:1 distilled HNO3 per 100 mL dilution should be substituted for the
distilled 1:1 HCI). Wash down the watch glass and beaker walls with deionized distilled
water and filter the sample to remove silicates and other insoluble material that could
clog the atomizer. Adjust the volume to some predetermined value based on the
expected concentrations of metals present. This volume will vary depending on the
metal to be determined. The sample is now ready for analysis. Concentrations so
determined shall be reported as "suspended." (See Note 4.)
NOTE 4: Certain metals such as antimony, arsenic, gold, iridium, mercury, osmium, palladium,
platinium, rhenium, rhodium, ruthenium, selenium, silver, thallium, tin, and titanium require
modification of the digestion procedure, and the individual sheets for these metals should
be consulted.
4.1.3 For the determination of total metals the sample is acidified with 1:1 redistilled HNO3
to a pH of 2 at the time of collection. The sample is not filtered before processing.
Choose a volume of sample appropriate for the expected level of metals. If much
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suspended material is present, as little as 50-100 mL of well mixed sample will most
probably be sufficient. (The sample volume required may also vary proportionally with
the number of metals to be determined.) Transfer a representative aliquot of the well
mixed sample to a Griffin beaker and add 3 mL of cone, redistilled HNO3. Place the
beaker on a hot plate and evaporate to dryness cautiously, making certain that the
sample does not boil. (DO NOT BAKE.) Cool the beaker and add another 3 mL portion
of cone, redistilled HNO3. Cover the beaker with a watch glass and return the beaker
to the hot plate. Increase the temperature of the hot plate so that a gentle reflux action
occurs. Continue heating and add additional acid as necessary until the digestion is
complete (generally indicated by a light colored residue or by no change in appearance
with continued refluxing). Again, evaporate to near dryness and cool the beaker. Add
a small quantity of redistilled 1:1 HCI (5 mL/100 mL of final solution) and warm the
beaker to dissolve any precipitate or residue resulting from evaporation. (If the sample
is to be analyzed by the furnace procedure, substitute distilled HNO3 for 1:1 HCI so that
the final dilution contains 0.5% (v/v) HNOJ. Wash down the beaker walls and watch
glass with distilled water and filter the sample to remove silicates and other insoluble
material that could clog the atomizer. Adjust the volume to some predetermined value
based on the expected metal concentrations. The sample is now ready for analysis.
Concentrations so determined shall be reported as "total." (See Note 4.)
4.1.4 To determine total recoverable metals, acidify the entire sample at the time of collection
with cone, redistilled HNO3, 5 mL/L At the time of analysis, a 100-mL aliquot of well
mixed sample is transferred to a beaker or flask. Five mL of distilled HCI (1:1) is added,
and the sample is heated on a steam bath or hot plate until the volume has been
reduced to 15-20 mL; be certain that the samples do not boil. (If the sample is being
prepared for furnace analysis, the same process should be followed except HCI should
be omitted.) After this treatment the sample is filtered to remove silicates and other
insoluble material that could clog the atomizer, and the volume is adjusted to 100 mL.
The sample is then ready for analysis. Concentrations so determined shall be reported
as "total." (See Notes 4, 5, and 6).
NOTE 5: The analyst should be cautioned that this digestion procedure may not be sufficiently
vigorous to destroy certain metal complexes if a colorimetric procedure is to be employed
for the final determination. When this is suspect, the more vigorous digestion given in
4.1.3 of this appendix should be followed.
NOTE 6: For drinking water analyses by direct aspiration, the final volume may be reduced to effect
up to a 10X concentration of the sample; provided that the total dissolved solids in the
original sample do not exceed 500 mg/L, the determination is corrected for any non-
specific absorbance, and there is not loss by precipitation.
5 Interferences
5.1 Direct Aspiration
5.1.1 The most troublesome type of interference in atomic absorption spectrophotometry is
usually termed "chemical" and is caused by lack of absorption of atoms bound in
molecular combination in the flame. This phenomenon can occur when the flame is not
sufficiently hot to dissociate the molecule, as in the case of phosphate interference with
magnesium, or because the dissociated atom is immediately oxidized to a compound
that will not dissociate further at the temperature of the flame. The addition of
lanthanum will overcome the phosphate interference in the magnesium, calcium, and
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barium determinations. Similarly, silica interference in the determination of manganese
can be eliminated by the addition of calcium.
5.1.2 Chemical interferences may also be eliminated by separating the metal from the
interfering material. While complexing agents are primarily employed to increase the
sensitivity of the analysis, they may also be used to eliminate or reduce interferences.
5.1.3 The presence of high dissolved solids in the sample may result in an interference from
non-atomic absorbance such as light scattering. If background correction is not
available, a non-absorbing wavelength should be checked. Preferably, high solids type
samples should be extracted (see 5.1.1 and 9.2).
5.1.4 lonization interferences occur where the flame temperature is sufficiently high to
generate the removal of an electron from a neutral atom, giving a positively charged ion.
This type of interference can generally be controlled by the addition, to both standard
and sample solutions of a large excess of an easily ionized element.
5.1.5 Although quite rare, spectral interference can occur when an absorbing wavelength of
an element present in the sample but not being determined falls within the width of the
absorption line of the element of interest. The results of the determination will then be
erroneously high because of the contribution of the interfering element to the atomic
absorption signal. Also, interference can occur when resonant energy from another
element in a multielement lamp or a metal impurity in the lamp cathode falls within the
bandpass of the slit setting and that metal is present in the sample. This type of
interference may sometimes be reduced by narrowing the slit width.
5.2 Flameless Atomization
5.2.1 Although the problem of oxide formation is greatly reduced with furnace procedures
because atomization occurs in an inert atmosphere, the technique is still subject to
chemical and matrix interferences. The composition of the sample matrix can have a
major effect on the analysis. It is those effects which must be determined and taken
into consideration in the analysis of each different matrix encountered. To help verify
the absence of matrix or of chemical interference, use the following procedure.
Withdraw from the sample two equal aliquots. To one of the aliquots. add a known
amount of analyte, and dilute both aliquots to the same predetermined volume. (The
dilution volume should be based on the analysis of the undiluted sample. Preferably,
the dilution should be 1:4 while keeping in mind the optimum concentration range of the
analysis. Under no circumstances should the dilution be less than 1:1). The diluted
aliquots should then be analyzed, and the unspiked results multiplied by the dilution
factor should be compared to the original determination. Agreement of the results
(within ±10%) indicates the absence of interference. Comparison of the actual signal
from the spike to the expected response from the analyte in an aqueous standard
should help confirm the finding from the dilution analysis. Those samples which indicate
the presence of interference should be treated in one or more of the following ways.
a. The samples should be successively diluted and reanalyzed to determine if the
interference can be eliminated.
b. The matrix of the sample should be modified in the furnace. Examples are the
addition of ammonium nitrate to remove alkali chlorides, ammonium phosphate to
retain cadmium, and nickel nitrate for arsenic and selenium analyses (Atomic
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Absorption Newsletter\]o\. 14, No. 5, p. 127, Sept.-Oct. 1975). The mixing of hydrogen
with the inert purge gas has also been used to suppress chemical interference. The
hydrogen acts as a reducing agent and aids in molecular dissociation.
c. Analyze the sample by method of standard additions while noting the precautions
and limitations of its use (see 8.5).
5.2.2 Gases generated in the furnace during atomization may have molecular absorption
bands encompassing the analytical wavelength. When this occurs, either the use of
background correction or choosing an alternate wavelength outside the absorption band
should eliminate this interference. Nonspecific broad band absorption interference can
also be compensated for with background correction.
5.2.3 Interference from a smoke-producing sample matrix can sometimes be reduced by
extending the charring time at a higher temperature or by utilizing an ashing cycle in the
presence of air. Care must be taken, however, to prevent loss of the analysis element.
5.2.4 Samples containing large amounts of organic materials should be oxidized by
conventional acid digestion prior to being placed in the furnace. In this way broad
band absorption will be minimized.
5.2.5 From anion interference studies in the graphite furnace, it is generally accepted that
nitrate is the preferred anion. Therefore, nitric acid is preferable for any digestion or
solubilization step. If another acid in addition to HN03 is required a minimum amount
should be used. This applies particularly to hydrochloric and to a lesser extent to
sulfuric and phosphoric acids.
5.2.6 Carbide formation resulting from the chemical environment of the furnace has been
observed with certain elements that form carbides at high temperatures. Molybdenum
may be cited as an example. When this takes place, the metal will be released very
slowly from the carbide as atomization continues. For molybdenum, one may be
required to atomize for 30 seconds or more before the signal returns to baseline levels.
This problem is greatly reduced, and the sensitivity is increased with the use of
pyrolytically-coated graphite.
5.2.7 lonization interferences have to date not been reported with furnace techniques.
5.2.8 For comments on spectral interference, see Section 5.1.5.
5.2.9 Contamination of the sample can be a major source of error because of the extreme
sensitivities achieved with the furnace. The sample preparation work area should be kept
scrupulously clean. All glassware should be cleaned as directed in section 6.9. Pipet
tips have been known to be a source of contamination. If suspected, they should be
acid soaked with 1:5 HNO3 and rinsed thoroughly with tap and deionized water. The use
of a better grade pipet tip can greatly reduce this problem. It is very important that
special attention be given to reagent blanks both in analysis and in the correction of
analytical results. Lastly, pyrolytic graphite, because of the production process and
handling, can become contaminated. As many as five to possibly ten high temperature
burns may be required to clean the tube before use.
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6 Apparatus
6.1 Atomic absorption spectrophotometer-Single or dual channel, singleor double-beam
instrument having a grating monochromator, photomultiplier detector, adjustable slits, a
wavelength range of 190 to 800 nm, and provisions for interfacing with a stripchart recorder.
6.2 Burner-The burner recommended by the particular instrument manufacturer should be used.
For certain elements the nitrous oxide burner is required.
6.3 Hollow cathode lamps-Single element lamps are to be preferred but multielement lamps
may be used. Electrodeless discharge lamps may also be used when available.
6.4 Graphite furnace-Any furnace device capable of reaching the specified temperatures is
satisfactory.
6.5 Stripchart recorder-A recorder is strongly recommended for furnace work so that there will
be a permanent record and any problems with the analysis such as drift, incomplete
atomization, losses during charring, changes in sensitivity, etc., can be easily recognized.
6.6 Pipets-Microliter with disposable tips. Sizes can range from 5 to 100 microliters as required.
NOTE 7: Pipet tips, which are white in color, do not contain CdS, and have been found suitable
for research work, are available from Ulster Scientific, Inc., 53 Main St., Highland, NY
12528 (914) 691-7500.
6.7 Pressure-reducing valves-The supplies of fuel and oxidant shall be maintained at pressures
somewhat higher than the controlled operating pressure of the instrument by suitable valves.
6.8 Separatory flasks-250 ml_, or larger, for extraction with organic solvents.
6.9 Glassware-All glassware, linear polyethylene, polypropylene or Teflon containers, including
sample bottles, should be washed with detergent, rinsed with tap water, 1:1 nitric acid, tap
water, 1:1 hydrochloric acid, tap water and, deionized distilled water in that order. [See
Notes 1 and 2 under (4.1) concerning the use of chromic acid and the cleaning procedure.]
6.10Borosilicate glass distillation apparatus.
7 Reagents
7.1 Deionized distilled water-Prepare by passing distilled water through a mixed bed of cation
and anion exchange resins. Use deionized distilled water for the preparation of all reagents,
calibration standards, and as dilution water.
7.2 Nitric acid (conc.)-If metal impurities are found to be present, distill reagent grade nitric
acid in a borosilicate glass distillation apparatus or use a spectrograde acid.
CAUTION: Distillation should be performed in hood with protective sash in place.
7.2.1 Nitric Acid (1:1)-Prepare a 1:1 dilution with deionized, distilled water by adding the cone.
acid to an equal volume of water.
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7.3 Hydrochloric acid (1:1)-Prepare a 1:1 solution of reagent grade hydrochloric acid and
deionized distilled water. If metal impurities are found to be present, distill this mixture
from a borosilicate glass distillation apparatus or use a spectrograde acid.
7.4 Stock standard metal solutions-Prepare as directed in 8.1 and under the individual metal
procedures. Commercially available stock standard solutions may also be used.
7.5 Calibration standards-Prepare a series of standards of the metal by dilution of the
appropriate stock metal solution to cover the concentration range desired.
7.6 Fuel and oxidant-Commercial grade acetylene is generally acceptable. Air may be supplied
from a compressed air line, a laboratory compressor, or from a cylinder of compressed air.
Reagent grade nitrous oxide is also required for certain determinations. Standard,
commercially available argon and nitrogen are required for furnace work.
7.7 Special reagents for the extraction procedure.
7.7.1 Pyrrolidine dithiocarbamic acid (PDCA)~[The name pyrrolidine dithiocarbamic acid
(PDCA), although commonly referenced in the scientific literature, is ambiguous. From
the chemical reaction of pyrrolidine and carbon disulf ide a more proper name would be
1-pyrrolidine.] Prepare by adding 18 mL of analytical reagent grade pyrrolidine to 500 mL
of chloroform in a liter flask. (See Note 8.) Cool and add 15 mL of carbon disulfide in
small portions and with swirling. Dilute to 1 liter with chloroform. The solution can be
used for several months if stored in a brown bottle in a refrigerator.
NOTE 8: An acceptable grade of pyrrolidine may be obtained from the Aldrich Chemical Co., 940
West St. Paul Ave., Milwaukee, WI 53233, (414) 273-3850.
7.7.2 Ammonium hydroxide, 2N-Dilute 13 mL cone. NH4OH to 100 mL with deionized distilled
water.
7.7.3 Bromophenol blue indicator (1 g/liter)~Dissolve 0.1g bromophenol blue in IOO mL of 50
percent ethanol or isopropanol.
7.7.4 HCI, 2.5% v/v~Dilute 2 mL redistilled HCI (6N) to 40 mL with deionized distilled water.
8 Preparation of Standards and Calibration
8.1 Stock standard solutions are prepared from high purity metals, oxides, or nonhygroscopic
spectroscopic grade salts using deionized distilled water and redistilled nitric or hydrochloric
acids. (See individual analysis sheets for specific instruction.) Sulfuric or phosphoric acids
should be avoided as they produce an adverse effect on many elements. The stock
solutions are prepared at concentrations of 1,000 mg of the metal per liter. Commercially
available standard solutions may also be used.
8.2 Calibration standards are prepared by diluting the stock metal solutions at the time of
analysis. For best results, calibration standards should be prepared fresh each time an
analysis is to be made and should be discarded after use. Prepare a blank and at least
four calibration standards in graduated amounts in the appropriate range. The calibration
standards should be prepared by using the same type of acid or combination of acids and
at the same concentration as will result in the samples after following processing. As
filtered water samples are carbodithioic acid, PCDA (CAS Registry No. 25769-03-3) preserved
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with 1:1 redistilled HNO3 (3 mL per liter), calibration standards for these analyses should be
similarly prepared with HNO3. Beginning with the blank and working toward the highest
standard, aspirate the solutions and record the readings. Repeat the operation with both
the calibration standards and the samples a sufficient number of times to secure a reliable
average reading for each solution. Calibration standards for furnace procedures should be
prepared as described on the individual sheets for that metal.
8.3 Where the sample matrix is so complex that viscosity, surface tension, and components
cannot be accurately matched with standards, the method of standard addition must be
used. This technique relies on the addition of small, known amounts of the analysis element
to portions of the sample-the absorbance difference between those and the original solution
giving the slope of the calibration curve. The method of standard addition is described in
greater detail in 8.5.
8.4 For those instruments which do not read out directly in concentration, a calibration curve
is prepared to cover the appropriate concentration range. Usually, this means the
preparation of standards which produce an absorption of 0 to 80 percent. The correct
method is to convert the percent absorption readings to absorbance and to plot that value
against concentration. The following relationship is used to convert absorption values to
absorbance:
absorbance = log (100/%T) = 2 - log % T
where: % T = 100 - % absorption
As the curves are frequently nonlinear, especially at high absorption values, the number of
standards should be increased in that portion of the curve.
8.5 Method of Standard Additions-ln this method, equal volumes of sample are added to a
deionized distilled water blank and to three standards containing different known amounts
of the test element. The volume of the blank and of the standards must be the same. The
absorbance of each solution is determined and is then plotted on the vertical axis of a
graph, with the concentrations of the known standards plotted on the horizontal axis. When
the resulting line is extrapolated back to zero absorbance, the point of interception of the
abscissa is the concentration of the unknown. The abscissa on the left side of the ordinate
is scaled the same as on the right side but in the opposite direction from the ordinate. An
example of a plot so obtained is shown in Figure 8-1, earlier in this manual. The method
of standard additions can be very useful; however, for the results to be valid the following
limitations must be taken into consideration:
a. The absorbance plot of sample and standards must be linear over the concentration
range of concern. For best results the slope of the plot should be nearly the same as
the slope of the aqueous standard curve. If the slope is significantly different (more than
20%), caution should be exercised.
b. The effect of the interference should not vary as the ratio of analyte concentration to
sample matrix changes, and the standard addition should respond in a similar manner
as the analyte.
c. The determination must be free of spectral interference and corrected for non-specific
background interference.
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9 General Procedure for Analysis by Atomic Absorption
9.1 Direct Aspiration: Differences between the various makes and models of satisfactory atomic
absorption spectrophotometers prevent the formulation of detailed instructions applicable
to every instrument. The analyst should follow the operating instructions provided by the
manufacturer for his particular instrument. In general, after choosing the proper hollow
cathode lamp for the analysis, the 'amp should be allowed to warm up for a minimum of
15 minutes unless operated in a double beam mode. During this period, align the
instrument, position the monochromator at the correct wavelength, select the proper
monochromator slit width, and adjust the hollow cathode current according to the
recommendation of the manufacturer. Subsequently, light the flame and regulate the flow
of fuel and oxidant, adjust the burner and nebulizer flow rate for maximum percent
absorption and stability, and balance the photometer. Run a series of standards of the
element under analysis and construct a calibration curve by plotting the concentrations of
the standards against the absorbance. For those instruments which read directly in
concentration, set the curve corrector to read out the proper concentration. Aspirate the
samples and determine the concentrations either directly or from the calibration curve. Stan-
dards must be run each time a sample or series of samples are run.
9.1.1 Calculation-Direct determination of liquid samples: Read the metal value in mg/L from
the calibration curve or directly from the readout system of the instrument.
9.1.1.1 If dilution of sample was required:
C+B
mg/L metal in sample = A
where:
A - mg/L of metal in diluted aliquot from calibration curve
B - mL of deionized distilled water used for dilution
C = mL of sample aliquot
9.1.2 For samples containing particulates:
V
mg/L metal in sample =
where:
A = mg/L of metal in processed sample from calibration curve
V = final volume of the processed sample in mL
C = mL of sample aliquot processed
9.1.3 For solid sample: report all concentrations as mg/kg dry weight.
9.1.3.1 Dry sample
mg metal/kg sample =
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where:
A - mg/L of metal in processed sample from calibration curve
V = final volume of the processed sample in mL
D = weight of dry sample in grams
9.1.3.2 Wet sample
mg metal/kg sample =
x(W)(P)
where:
A - mg/L of metal in processed sample from calibration curve
V = final volume of the processed sample in mL
W= weight of wet sample in grams
P = % solids
9.2 Special Extraction Procedure: When the concentration of the metal is not sufficiently high
to determine directly or when considerable dissolved solids are present in the sample,
certain metals may be chelated and extracted with organic solvents. Ammonium pyrrolidine
dithiocarbamate (APDC) [The name ammonium pyrrolidine dithiocarbamate (APDC) is
somewhat ambiguous and should more properly be called ammonium 1-pyrrolidine
carbodithioate (APCD), CAS Registry No. 5108-96-3] in methyl isobutyl ketone (MIBK) is
widely used for this purpose and is particularly useful for zinc, cadmium, iron, manganese,
copper, silver, lead, and chromium46. Trivalent chromium does not react with APDC unless
it has first been converted to the hexavalent form (Atomic Absorption Newsletter Q, p. 128,
1967). This procedure is described under Method 218.3. Aluminum, beryllium, barium, and
strontium also do not react with APDC. While the APDCMIBK chelating-solvent system can
be used satisfactorily, it is possible to experience difficulties. (See Note 9.)
NOTE 9: Certain metal chelates, manganese-APDC in particular, are not stable in MIBK and will
redissplve into the aqueous phase on standing. The extraction of other metals is
sensitive to both shaking rate and time. As with cadmium, prolonged extraction beyond
1 minute will reduce the extraction efficiency, whereas 3 minutes of vigorous shaking is
required for chromium. Also, when multiple metals are to be determined, either larger
sample volumes must be extracted or individual extractions must be made for each metal
being determined. The acid form of APDC-pyrrolidine dithiocarbamic acid prepared directly
in chloroform as described by Lakanen {(Atomic Absorption Newsletter 5, p. 17 (1966)]
(see 7.7.1) has been found to be most advantageous. In this procedure the more dense
chloroform layer allows for easy combination of multiple extractions which are carried out
over a broader pH range favorable to multielement extractions. Pyrrolidine dithiocarbamic
acid in chloroform is very stable and may be stored in a brown bottle in the refrigerator
for months. Because chloroform is used as the solvent, it may not be aspirated into the
flame. The following procedure is suggested.
9.2.1 Extraction Procedure with pyrrolidine dithiocarbamic acid (PDCA) in chloroform.
9.2.1.1 Transfer 200 mL of sample into a 250 mL separatory funnel, add 2 drops
bromophenol blue indicator solution (7.7.3), and mix.
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9.2.1.2 Prepare a blank and sufficient standards in the same manner and adjust the
volume of each to approximately 200 ml_ with deionized distilled water. All of
the metals to be determined may be combined into single solutions at the
appropriate concentration levels.
9.2.1.3 Adjust the pH by addition of 2N NH4OH solution (7.7.2) until a blue color persists.
Add HCI (7.7.4) dropwise until the blue color just disappears; then add 2.0 mL
HCI (7.7.4) in excess. The pH at this point should be 2.3. (The pH adjustment
may be made with a pH meter instead of by using indicator.)
9.2.1.4 Add 5 mL of PDCA-chloroform reagent (7.7.1) and shake vigorously for 2 minutes.
Allow the phases to separate and drain the chloroform layer into a 100 ml
beaker. (See NOTE 10.)
NOTE 10: If hexavalent chromium is to be extracted, the aqueous phase must be readjusted back
to a pH of 2.3 after the addition of PDCA-chloroform and must be maintained at that
pH throughout the extraction. For multielement extraction, the pH may be adjusted
upward after the chromium has been extracted.
9.2.1.5 Add a second portion of 5 mL PDCA-chloroform reagent (7.7.1) and shake
vigorously for 2 minutes. Allow the phases to separate. Drain the chloroform
phase and combine with that obtained in step (9.2.1.4).
9.2.1.6 Determine the pH of the aqueous phase and adjust to 4.5.
9.2.1.7 Repeat step (9.2.1.4) again combining the solvent extracts.
9.2.1.8 Readjust the pH to 5.5, and extract a fourth time. Combine all extracts and
evaporate to dryness on a steam bath.
9.2.1.9 Hold the beaker at a 45 degree angle and slowly add 2 mL of cone, distilled nitric
acid while rotating the beaker to effect thorough contact of the acid with the
residue.
9.2.1.10 Place the beaker on a low temperature hotplate or steam bath and evaporate
just to dryness.
9.2.1.11 Add 2 mL of nitric acid (1:1) to the beaker and heat for 1 minute. Cool,
quantitatively transfer the solution to a 10 mL volumetric flask, and bring to volume
with distilled water. The sample is now ready for analysis.
9.2.2 Prepare a calibration curve by plotting absorbance versus the concentration of the
metal standard (ug/L) in the 200 mL extracted standard solution. To calculate sample
concentration, read the metal value in pig/L from the calibration curve or directly from
the readout system of the instrument. If dilution of the sample was required, use the
following equation:
/C+B
pg/L metal in sample = Z
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where:
Z = jug/L of metal in diluted aliquot from calibration curve
B = mL of deionized distilled water used for dilution
C = mL of sample aliquot
9.3 Furnace Procedure: Furnace devices (flameless atomization) are a most useful means of
extending detection limits. Because of differences between various makes and models of
satisfactory instruments, no detailed operating instuctions can be given for each instrument.
Instead, the analyst should follow the instructions provided by the manufacturer of his
particular instrument and should use as a guide the temperature settings and other
instrument conditions listed on the individual analysis sheets which are recommended for
the Perkin-Elmer HGA-2100. In addition, the following points may be helpful.
9.3.1 With flameless atomization, background correction becomes of high importance
especially below 350 nm. This is because certain samples when atomized may absorb
or scatter light from the hollow cathode lamp. It can be caused by the presence of
gaseous molecular species, salt particules, or smoke in the sample beam. If no
correction is made, sample absorbance will be greater than it should be, and the
analytical result will be erroneously high.
9.3.2 If during atomization all the analyte is not volatilized and removed from the furnace,
memory effects will occur. This condition is dependent on several factors such as the
volatility of the element and its chemical form, whether pyrolytic graphite is used, the
rate of atomization, and furnace design. If this situation is detected through blank
burns, the tube should be cleaned by operating the furnace at full power for the required
time period as needed at regular intervals in the analytical scheme.
9.3.3 Some of the smaller size furnace devices, or newer furnaces equipped with feedback
temperature control (Instrumentation Laboratories Model 555, Perkin-Elmer Models HGA
2200 and HGA 76B, and Varian Model CRA-90) employing faster rates of atomization,
can be operated using lower atomization temperatures for shorter time periods than
those listed in this manual.
9.3.4 Although prior digestion of the sample in many cases is not required when a
representative aliquot of sample can be pipeted into the furnace, it will provide for a
more uniform matrix and possibly will lessen matrix effects.
9.3.5 Inject a measured microliter aliquot of sample into the furnace and atomize. If the
concentration found is greater than the highest standard, the sample should be diluted
in the same acid matrix and reanalyzed. The use of multiple injections can improve
accuracy and can help detect furnace pipetting errors.
9.3.6 To verify the absence of interference, follow the procedure as given in 5.2.1.
9.3.7 A check standard should be run approximately after every 10 sample injections.
Standards are run in part to monitor the life and performance of the graphite tube.
Lack of reproducibility or significant change in the signal for the standard indicates
that the tube should be replaced. Even though tube life depends on sample matrix
and atomization temperature, a conservative estimate would be that a tube will last at
least 50 firings. A pyrolytic coating would extend that estimate by a factor of 3.
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9.3.8 Calculation-For determination of metal concentration by the furnace: Read the metal
value in fjg/L from the calibration curve or directly from the readout system of the
instrument.
9.3.8.1 If different size furnace injection volumes are used for samples than for
standards:
/
S
of metal in sample = Z
. U
where:
Z = pg/L of metal read from calibration curve or readout system
S = juL volume standard injected into furnace for calibration curve
U = piL volume of sample injected for analysis
9.3.8.2 If dilution of sample was required and if sample injection volume is the same
as for the standard:
C+B'
of metal in sample = Z
where:
Z = fjg/L metal in diluted aliquot from calibration curve
B = mL of deionized distilled water used for dilution
C = ml of sample aliquot
9.3.9 For sample containing particulates:
/ V\
fjg/L of metal in sample = Z
\C/
where:
Z = jug/L of metal in processed sample from calibration curve (See 9.3.8.1)
V = final volume of processed sample in mL
C = mL of sample aliquot processed
9.3.10For solid samples: Report all concentration as mg/kg dry weight.
9.3.10.1 Dry sample:
mg metal/kg sample =
(1000)(D)
where:
Z = pg/L of metal in processed sample from calibration curve (See 9.3.8.1)
V = final volume of processed sample in mL
D = weight of dry sample in grams
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9.3.10.2 Wet sample:
mg metal/kg sample =
(W)(P)(1000)
a
where:
Z = /ug/L of metal in processed sample from calibration curve (See 9.3.8.1)
V = final volume of processed sample in mL
W= weight of dry sample in grams
P = % solids
10 Quality Control For Drinking Water Analysis
10.1 Minimum requirements
10.1.1 All quality control data should be maintained and should be available for easy reference
or inspection.
10.1.2 An unknown performance sample (when available) must be analyzed once per year for
the metals measured. Results must be within the control limit established by EPA. If
problems arise, they should be corrected, and a follow-up performance sample should
be analyzed.
10.2 Minimum Daily Control
10.2.1 After a calibration curve composed of a minimum of a reagent blank and three
standards has been prepared, subsequent calibration curves must be verified by use
of at least a reagent blank and one standard at or near the MDL. Daily checks must
be within ±10 percent of original curve.
10.2.2 If 20 or more samples per day are analyzed, the working standard curve must be
verified by running an additional standard at or near the MDL every 20 samples.
Checks must be within ±10 percent of original curve.
10.3 Optional Requirements
10.3.1 A current service contract should be in effect on balances and on the atomic absorption
spectrophotometer.
10.3.2 Class S weights should be available to make periodic checks on balances.
10.3.3 Chemicals should be dated upon receipt of shipment and replaced as needed or before
shelf life has been exceeded.
10.3.4 A known reference sample (when available) should be analyzed once per quarter for
the metals measured. The measured value should be within the control limits.
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10.3.5 At least one duplicate sample should be run every 10 samples or with each set of
samples to verify precision of the method. Checks should be within the control limits
established by EPA.
10.3.6 Standard deviation should be obtained and documented for all measurements being
conducted.
10.3.7 Quality control charts or a tabulation of mean and standard deviation should be used
to document validity of data on a daily basis.
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Appendix B
Inductively Coupled Plasma Atomic Emission Spectrometric
Method for Trace Element Analysis of Water and Wastes
1 Scope and Application
1.1 This method may be used for the determination of dissolved, suspended, or total elements
in drinking water, surface water, domestic and industrial wastewaters.
1.2 Dissolved elements are determined in filtered and acidified samples. Appropriate steps
must be taken in all analyses to ensure that potential interferences are taken into account.
This is especially true when dissolved solids exceed 1500 mg/L (See 5.)
1.3 Total elements are determined after appropriate digestion procedures are performed. Since
digestion techniques increase the dissolved solids content of the samples, appropriate
steps must be taken to correct for potential interference effects. (See 5.)
1.4 Table B-1 lists elements for which this method applies along with recommended
wavelengths for sequential instruments and typical estimated instrumental detection limits
using conventional pneumatic nebulization. Actual working detection limits are sample
dependent and as the sample matrix varies, these concentrations may also vary. In time,
other elements may be added as more information becomes available and as required.
1.5 Because of the differences between various makes and models of satisfactory
instruments, no detailed instrumental operating instructions can be provided. Instead, the
analyst is referred to the instructions provided by the manufacturer of the particular
instrument.
2 Summary of Method
2.1 The method describes a technique for the simultaneous or sequential multielement
determination of trace elements in solution. The basis of the method is the measurement
of atomic emission by an optical spectroscopic technique. Samples are nebulized, and
the aerosol that is produced is transported to the plasma torch where excitation occurs.
Characteristic atomic-line emission spectra are produced by a radio-frequency inductively
coupled plasma (ICP). The spectra are dispersed by a grating spectrometer, and the
intensities of the lines are monitored by photomultiplier tubes. The photocurrents from the
photomultiplier tubes are processed and are controlled by a computer system. A
background correction technique is required to compensate for variable background
contribution to the determination of trace elements. Background must be measured
adjacent to analyte lines on samples during analysis. The position selected for the
background intensity measurement, on either or both sides of the analytical line, will be
determined by the complexity of the spectrum adjacent to the analyte line. The posititon
used must be free of spectral interference and must reflect the same change in
background intensity as occurs at the analyte wavelength measured. Background
correction is not required in cases of line broadening where a background correction
measurement would actually degrade the analytical result. The possibility of additional
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Table B-1. Recommended Wavelengths' and Estimated Instrumental Detection Limits
Element Wavelength, nm Estimated detection limit. pg/L"
Aluminum
Arsenic
Antimony
Barium
Beryllium
Boron
Cadmium
Calcium
Chromium
Cobalt
Copper
Iron
Lead
Magnesium
Manganese
Molybdenum
Nickel
Potassium
Selenium
Silicon
Silver
Sodium
Thallium
Vanadium
Zinc
308.215
193.696
206.833
455.403
313.042
249.773
226.502
317.933
267.716
228.616
324.754
259.940
220.353
279.079
257.610
202.030
231.604
766.491
196.026
288.158
328.068
588.995
190.864
292.402
213.856
45
53
32
2
0.3
5
4
10
7
7
6
7
42
30
2
8
15
seec
75
58
7
29
40
8
2
* The wavelengths listed are recommended for sequential instruments because of their sensitivity and overall
acceptance. Other wavelengths may be substituted if they can provide the needed sensitivity and if they are treated
with the same corrective techniques for spectral interference. (See 5.1.1.)
The estimated instrumental detection limits as shown are taken from "Inductively Coupled Plasma Atomic Emission
Spectroscopy-Prominent Lines," EPA-600/4-79-017. They are given as a guide for an instrumental limit. The actual
method detection limits are sample dependent and may vary as the sample matrix varies.
c Highly dependent on operating conditions and plasma position.
interferences named in 5.1 (and tests for their presence as described in 5.2) should also be
recognized, and appropriate corrections should be made.
3 Definitions
3.1 Disso/ued-Those elements which will pass through a 0.45 pm membrane filter.
3.2 Suspended-Jbose elements which are retained by a 0.45 pm membrane filter.
3.3 Totat-ThQ concentration determined on an unfiltered sample following vigorous digestion
(Section 9.3), or the sum of the dissolved plus suspended concentrations (Section 9.1 plus
9.2).
3.4 Total recoverabte--TY\e concentration determined on an unfiltered sample following
treatment with hot, dilute mineral acid (Section 9.4).
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3.5 Instrumental detection //m/t-The concentration equivalent to a signal due to the analyte
and which is equal to three times the standard deviation of a series of ten replicate
measurements of a reagent blank signal at the same wavelength.
3.6 Sensitivity~~ft\e slope of the analytical curve, i.e., functional relationship between emission
intensity and concentration.
3.7 Instrument check standard-k multielement standard of known concentrations prepared
by the analyst to monitor and to verify instrument performance on a daily basis. (See
Section 7.6.1.)
3.8 Interference check sample-k solution containing both interfering and analyte elements
of known concentration that can be used to verify background and interelement correction
factors. (See Section 7.6.2.)
3.9 Quality control sample-k solution obtained from an outside source having known,
concentration values to be used to verify the calibration standards. (See Section 7.6.3.)
3.10 Calibration standards-k series of known standard solutions used by the analyst for
calibration of the instrument (i.e., preparation of the analytical curve). (See Section 7.4.)
3.11 Linear dynamic range-The concentration range over which the analytical curve remains
linear.
3.12 Reagent blank-k volume of deionized, distilled water containing the same acid matrix as
the calibration standards carried through the entire analytical scheme. (See Section 7.5.2.)
3.13 Calibration blank-k volume of deionized, distilled water acidified with HNO3 and HCI.
(See Section 7.5.1.)
3.14 Method of standard addif/on-The standard addition technique involves the use of the
unknown and the unknown plus a known amount of standard. (See Section 10.6.1.)
4 Safety
4.1 The toxicity or carcinogenicity of each reagent used in this method has not been precisely
defined; however, each chemical compound should be treated as a potential health hazard.
From this viewpoint, exposure to these chemicals must be reduced to the lowest possible
level by whatever means available. The laboratory is responsible for maintaining a current
awareness file of OSHA regulations regarding the safe handling of the chemicals specified
in this method. A reference file of material data handling sheets should also be made
available to all personnel involved in the chemical analysis. Additional references to
laboratory safety are available and have been identified (14.7, 14.8, and 14.9) for the
information of the analyst.
5 Interferences
5.1 Several types of interference effects may contribute to inaccuracies in the determination
of trace elements. They can be summarized as follows:
5.1.1 Spectral interferences can be categorized as (1) overlap of a spectral line from another
element, (2) unresolved overlap of molecular band spectra, (3) background contribution
from continuous or recombination phenomena, and (4) background contribution from
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stray light from the line emission of high concentration elements. The first of these
effects can be compensated by utilizing a computer correction of the raw data
requiring the monitoring and measurement of the interfering element. The second
effect may require selection of an alternate wavelength. The third and fourth effects
can usually be compensated by a background correction adjacent to the analyte line.
In addition, users of simultaneous multielement instrumentation must assume the
responsibility of verifying the absence of spectral interference from an element that
could occur in a sample but for which there is no channel in the instrument array.
Listed in Table B-2 are some interference effects for the recommended wavelengths
given in Table B-1. The data in Table B-2 are intended for use only as a rudimentary
guide for the indication of potential spectral interferences. For this purpose, linear
relations between concentration and intensity for the analytes and the interferents can
be assumed. The interference information, which was collected at the Ames
Laboratory [Ames Laboratory, USDOE, Iowa State University, Ames, Iowa 50011], is
expressed as analyte concentration eqivalents (i.e., false analyte concentrations)
arising from 100 mg/L of the interferent element. The suggested use of this
information is as follows: Assume that arsenic (at 193.696 nm) is to be determined
in a sample containing approximately 10 mg/L of aluminum. According to Table B-2,
100 mg/L of aluminum would yield a false signal for arsenic equivalent to
approximately 1.3 mg/L. Therefore, 10 mg/L of aluminum would result in a false signal
for arsenic equivalent to approximately 0.13 mg/L. The reader is cautioned that other
analytical systems may exhibit somewhat different levels of interference than those
shown in Table B-2 and that the interference effects must be evaluated for each
individual system.
Only those interferents listed were investigated, and the blank spaces in Table B-2
indicate that measurable interferences were not observed for the interferent
concentrations listed in Table B-3. Generally, interferences were discernible if they
produced peaks or background shifts corresponding to 2-5% of the peaks generated
by the analyte concentrations also listed in Table B-3.
At present, information on the listed silver and potassium wavelengths are not
available, but it has been reported that second order energy from the magnesium
383.231 nm wavelength interferes with the listed potassium line at 766.491 nm.
5.1.2 Physical interferences are generally considered to be effects associated with the
sample nebulization and transport processes. Such properties as change in viscosity
and surface tension can cause significant inaccuracies especially in samples which
may contain high dissolved solids or acid concentrations, or both. The use of a
peristaltic pump may lessen these interferences. If these types of interferences are
operative, they must be reduced by dilution of the sample or utilization of standard
addition techniques. Another problem which can occur from high dissolved solids is
salt buildup at the tip of the nebulizer. This affects aerosol flow rate and causes
instrumental drift. Wetting the argon prior to nebulization, the use of a tip washer,
or sample dilution have been used to control this problem. Also, it has been reported
that better control of the argon flow rate improves instrument performance. This is
accomplished with the use of mass flow controllers.
5.1.3 Chemical Interferences are characterized by molecular compound formation, ionization
effects, and solute vaporization effects. Normally these effects are not pronounced
with the ICP technique; however, if observed, they can be minimized by careful
selection of operating conditions (that is, incident power, observation position, and
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Table B-2. Analyte Concentration Equlvalenta (mg/L) Arlaing From Interferenta at the 100 mg/L Level
Analvte Wavelenath.
nm
Aluminum
Antimony
Arsenic
308.215
206.833
193.696
Al
0.47
1.3
Ca Cr
— 2.9
— 0.44
Interferent
Cu Fe
— 0.08
Mg Mn Ni
— 0.21 —
Ti
.25
Y
1.4
0.45
1.1
Barium 455.403 —
Beryllium 313.042 -
Boron 249.773 0.04
Cadmium 226.502 —
Calcium 317.933 —
Chromium 267.716 —
Cobalt 228.616 —
Copper 324.754 —
Iron 259.940 ~
Lead 220.353 0.17
Magnesium 279.079 —
Manganese 257.610 0.005
0.02
0.08
0.03
0.11
0.01
Molybdenum 202.030 0.05 —
Nickel
Selenium
Silicon
Sodium
Thallium
Vanadium
Zinc
231.604 —
196.026 0.23
288.158 —
588.995 —
190.864 0.30
292.402 -
213.856 —
0.32
0.03
0.01
0.003
0.005
0.003
0.13
0.002
0.03
0.09
0.01
0.04
0.04
— 0.04
0.02 —
— 0.03
0.03
— 0.12
— 0.25
0.002 —
0.15
0.05
0.07
0.05
0.03
0.04
0.02
0.12
— 0.07 -
0.05
0.14
0.005 -
— 0.08
- 0.02
0.29 -
0.01
Table B-3. Interferent and Analyte Elemental Concentration* Used for Interference Measurement* In Table B-2
Analvtes
Al
As
B
Ba
Be
Ca
Cd
Co
Cr
Cu
Fe
Mg
Mn
Mo
Na
Ni
Pb
Sb
Se
Si
TI
V
Zn
fma/U
10
10
10
1
1
1
10
1
1
1
1
1
1
10
10
10
10
10
10
1
10
1
10
Interferents
Al
Ca
Cr
Cu
Fe
Mg
Nn
Ni
71
V
(ma/L)
1000
1000
200
200
1000
1000
200
200
200
200
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so forth), by buffering of the sample, by matrix matching, and by standard addition proced-
ures. These types of interferences can be highly dependent on matrix type and the specific
analyte element.
5.2 It is recommended that whenever a new or unusual sample matrix is encountered, a series
of tests be performed prior to reporting concentration data for analyte elements. These
tests, as outlined in 5.2.1 through 5.2.4, will ensure the analyst that neither positive nor
negative interference which would distort effects the accuracy of the reported values are
operative on any of the analyte elements.
5.2.1 Serial dilution--If the analyte concentration is sufficiently high (minimally a factor of
10 above the instrumental detection limit after dilution), an analysis of a dilution
should agree within 5 percent of the original determination [or within some acceptable
control limit (14.3) that has been established for that matrix]. If not, a chemical or
physical interference effect should be suspected.
5.2.2 Spiked addition-The recovery of a spiked addition added at a minimum level of 10X
the instrumental detection limit (maximum 100X) to the original determination should
be recovered to within 90 to 110 percent or within the established control limit for that
matrix. If not, a matrix effect should be suspected. The use of a standard addition
analysis procedure can usually compensate for this effect.
CAUTION: The standard addition technique does not detect coincident spectral overlap. If
suspected, use of computerized compensation, an alternate wavelength, or comparison
with an alternate method is recommended (See Section 5.2.3).
5.2.3 Comparison with alternate method of analysis--When investigating a new sample
matrix, a comparison test may be performed with other analytical techniques such
as atomic absorption spectrometry or other approved methodology.
5.2.4 Wavelength scanning of analyte line region-If the appropriate equipment is available,
wavelength scanning can be performed to detect potential spectral interferences.
6 Apparatus
6.1 Inductively Coupled Plasma Atomic Emission Spectrometer.
6.1.1 Computer-controlled atomic emission spectrometer with background correction.
6.1.2 Radiofrequency generator.
6.1.3 Argon gas supply, welding grade or better.
6.2 Operating conditions-Because of the differences between various makes and models of
satisfactory instruments, no detailed operating instructions can be provided. Instead, the
analyst should follow the instructions provided by the manufacturer of the particular
instrument. Sensitivity, instrumental detection limit, precision, linear dynamic range, and
interference effects must be investigated and established for each individual analyte line
on that particular instrument. It is the responsibility of the analyst to verify that the
instrument configuration and operating conditions used satisfy the analytical requirements
and to maintain quality control data confirming instrument performance and analytical
results.
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7 Reagents and Standards
7.1 Acids used in the preparation of standards and for sample processing must be ultra-high
purity spectroscopic grade or equivalent. Redistilled acids are acceptable.
7.1.1 Acetic acid, cone, (sp gr 1.06).
7.1.2 Hydrochloric acid, cone, (sp gr 1.19).
7.1.3 Hydrochloric acid, (1+1)-Add 500 ml_ cone. HCI (sp gr 1.19) to 400 ml_ deionized,
distilled water and dilute to 1 liter.
7.1.4 Nitric acid, cone, (sp gr 1.41).
7.1.5 Nitric acid, (1+1)--Add 500 mL cone. HN03 (sp. gr 1.41) to 400 ml deionized distilled
water and dilute to 1 liter.
7.2 Deionized, distilled water-Prepare by passing distilled water through a mixed bed of cation
and anion exchange resins. Use deionized, distilled water for the preparation of all
reagents, calibration standards, and as dilution water. The purity of this water must be
equivalent to ASTM Type II reagent water of Specification D 1193 (14.6).
7.3 Standard stock solutions may be purchased or prepared from ultra high purity grade
chemicals or metals. All salts must be dried for 1 h at 105 °C unless otherwise specified.
CAUTION: Many metal salts are extremely toxic and may be fatal if swallowed. Wash hands
thoroughly after handling.
Typical stock solution preparation procedures follow:
7.3.1 Aluminum solution, stock, 1 mL = 100 jug AI-Dissolve 0.100 g of aluminum metal in
an acid mixture of 4 mL of (1+1) HCI and 1 mL of cone. HNO3 in a beaker. Warm
gently to effect solution. When solution is complete, transfer quantitatively to a 1 liter
volumetric flask, add an additional 10 mL of (1+1) HCI and dilute to 1,000 mL with
deionized, distilled water.
7.3.2 Antimony solution stock, 1 mL = 100 pg Sb~Dissolve 0.2669 g K(SbO)C4H4O6 in
deionized distilled water, add 10 mL (1 + 1) HCI and dilute to 1000 mL with deionized,
distilled water.
7.3.3 Arsenic solution, stock, 1 mL = 100 ^g As-Dissolve 0.1320 g of As2O3 in 100 mL of
deionized, distilled water containing 0.4 g NaOH. Acidify the solution with 2 mL cone.
HNO3 and dilute to 1,000 mL with deionized, distilled water.
7.3.4 Barium solution, stock, 1 mL = 100 fig Ba-Dissolve 0.1516 g BaCI2 (dried at 250° for
2 hrs) in 10 mL deionized, distilled water with 1 mL (1+1) HCI. Add 10.0 mL (1+1)
HCI and dilute to 1,000 mL with deionized, distilled water.
7.3.5 Beryllium solution, stock, 1 mL = 100 jug Be-Do not dry. Dissolve 1.966 g BeSO4»4H2O
in deionized, distilled water, add 10.0 mL cone. HNO3, and dilute to 1,000 mL with
deionized, distilled water.
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7.3.6 Boron solution, stock, 1 ml_ = 100 fjg B-Do not dry. Dissolve 0.5716 g anhydrous
H3BO3 in deionized, distilled water and dilute to 1,000 ml_. Use a reagent meeting
ACS specifications, keep the bottle tightly stoppered, and store in a desiccator to
prevent the entrance of atmospheric moisture.
7.3.7 Cadmium solution, stock, 1 ml_ = 100 fjg Cd-Dissolve 0.1142 g CdO in a minimum
amount of (1 + 1) HNO3. Heat to increase rate of dissolution. Add 10.0 ml_ cone. HNO3
and dilute to 1,000 mL with deionized, distilled water.
7.3.8 Calcium solution, stock, 1 mL = 100 pg Ca-Suspend 0.2498 g CaCO3. dried at 180 °C
for 1 h before weighing, in deionized, distilled water and dissolve cautiously with a
minimum amount of (1 + 1) HNO3. Add 10.0 mL cone. HNO3 and dilute to 1,000 mL with
deionized, distilled water.
7.3.9 Chromium solution, stock, 1 mL = 100 /vg Cr--Dissolve 0.1923 g of CrO3 in deionized,
distilled water. When solution is complete, acidify with 10 mL cone. HNO3 and dilute
to 1,000 mL with deionized, distilled water.
7.3.10 Cobalt solution, stock, 1 mL = 100 pg Co-Dissolve 0.1000 g of colbalt metal in a
minimum amount of (1 + 1) HNO3. Add 10.0 mL (1 + 1) HCI and dilute to 1,000 mL with
deionized, distilled water.
7.3.11 Copper solution, stock, 1 mL = 100 ng Cu--Dissolve 0.1252 g CuO in a minimum
amount of (1 + 1) HNO3. Add 10.0 mL cone. HNO3 and dilute to 1,000 mL with deionized,
distilled water.
7.3.12 Iron solution, stock, 1 mL = IOO jug Fe-Dissolve 0.1430 g Fe2O3 in a warm mixture of
20mL (1 + 1) HCI and 2 mL of cone. HNO3. Cool, add an additional 5 mL of cone.
HNO3, and dilute to 1,000 mL with deionized, distilled water.
7.3.13 Lead solution, stock, 1 mL = 100 jig Pb~Dissolve 0.1599 g PbfNOJ;, in a minimum
amount of (1 + 1) HNO3. Add 10.0 mL cone. HNO3 and dilute to 1,000 mL with deionized,
distilled water.
7.3.14 Magnesium solution, stock, 1 mL = 100 jug Mg-Dissolve 0.1658 g MgO in a minimum
amount of (1 + 1) HNO3. Add 10.0 mL cone. HNO3 and dilute to 1,000 mL with deionized,
distilled water.
7.3.15 Manganese solution, stock, 1 mL = 100 ^g Mo-Dissolve 0.1000 g of manganese metal
in the acid mixture 10 mL cone. HCI and 1 mL cone. HNO3, and dilute to 1,000 mL with
deionized, distilled water.
7.3.16 Molybdenum solution, stock, 1 mL = IOO ng Mo-Dissolve 0.2043 g (NH4)2MoO4 in
deionized, distilled water and dilute to 1,000 mL
7.3.17 Nickel solution, stock, 1 mL = 100 pg Mi-Dissolve 0.1000 g of nickel metal in 10 mL
hot cone. HNO3, cool, and dilute to 1,000 mL with deionized, distilled water.
7.3.18 Potassium solution, stock, 1 mL = 100 /jg K-Dissolve 0.1907 g KCI, dried at 110 °C,
in deionized, distilled water and dilute to 1,000 mL.
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7.3.19 Selenium solution, stock, 1 ml = 100 jug Se-Do not dry. Dissolve 0.1727 g H2SeO3
(actual assay 94.6%) in deionized, distilled water and dilute to 1,000 mL
7.3.20Silica solution, stock, 1 mL = 100 jug SiO2--£to not dry. Dissolve 0.4730 g Na2SiO3«9H2O
in deionized, distilled water. Add 10.0 mL cone. HNO3 and dilute to 1,000 mL with
deionized, distilled water.
7.3.21 Silver solution, stock, 1 mL = 100 jug Ag-Dissolve 0.1575 g AgNO3 in 100 mL of
deionized, distilled water and 10 mL cone. HNO3. Dilute to 1,000 mL with deionized,
distilled water.
7.3.22Sodium solution, stock, 1 mL = 100 /jg Na-Dissolve 0.2542 g NaCI in deionized,
distilled water. Add 10.0 mL cone. HNO3 and dilute to 1,000 mL with deionized, distilled
water.
7.3.23Thallium solution, stock, 1 mL = 100 \XQ TI-Dissolve 0.1303 g TINO3 in deionized,
distilled water. Add 10 mL cone. HNO3 and dilute to 1,000 mL with deionized, distilled
water.
7.3.24 Vanadium solution, stock, 1 mL = 100 pg V-Dissolve 0.2297 NH4VO3 in a minimum
amount of cone. HNO3. Heat to increase rate of dissolution. Add 10.0 mL cone. HNO3
and dilute to 1,000 mL with deionized, distilled water.
7.3.25Zinc solution, stock, 1 mL = 100 /jg Zn-Dissolve 0.1245 g ZnO in a minimum amount
of dilute HNO3. Add 10.0 mL cone. HNO3 and dilute to 1,000 mL with deionized,
distilled water.
7.4 Mixed calibration standard solutions-Prepare mixed calibration standard solutions by
combining appropriate volumes of the stock solutions in volumetric flasks. (See Sections
7.4.1 thru 7.4.5.) Add 2 mL of (1+1) HNO3 and 10 mL of (1+1) HCI and dilute to 100 mL with
deionized, distilled water. (See Notes 1 and 6.) Prior to preparing the mixed standards,
each stock solution should be analyzed separately to determine possible spectral
interference or the presence of impurities. Care should be taken when preparing the mixed
standards that the elements are compatible and stable. Transfer the mixed standard
solutions to a FEP fluorocarbon or unused polyethylene bottle for storage. Fresh mixed
standards should be prepared as needed with the realization that concentration can
change on aging. Calibration standards must be initially verified by using a quality control
sample and must be monitored weekly for stability (see Section 7.6.3). Although not
specifically required, some typical calibration standard combinations follow which use
those specific wavelengths listed in Table B-1.
7.4.1 Mixed standard solution I-Manganese, beryllium, cadmium, lead, and zinc.
7.4.2 Mixed standard solution II-Barium, copper, iron, vanadium, and colbalt.
7.4.3 Mixed standard solution Ill-Molybdenum, silica, arsenic, and selenium.
7.4.4 Mixed standard solution IV~Calcium, sodium, potassium, aluminum, chromium, and
nickel.
7.4.5 Mixed standard solution V-Antimony, boron, magnesium, silver, and thallium.
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NOTE 1: If the addition of silver to the recommended acid combination results in an initial
precipitation, add 15 mL of deionized distilled water and warm the flask until the solution
clears. Cool and dilute to 100 mL with deionized, distilled water. For this acid combination
the silver concentration should be limited to 2 mg/L Silver under these conditions is stable
in a tap water matrix for 30 days. Higher concentrations of silver require additional HCI.
7.5 Two types of blanks are required for the analysis. The calibration blank (3.13) is used in
establishing the analytical curve while the reagent blank (3.12) is used to correct for
possible contamination resulting from varying amounts of the acids used in the sample
processing.
7.5.1 The calibration blank is prepared by diluting 2 mL of (1+1) HNO3 and 10 mL of (1+1)
HCI to 100 mL with deionized, distilled water. (See Note 6.) Prepare a sufficient
quantity to be used to flush the system between standards and samples.
7.5.2 The reagent blank must contain all the reagents and in the same volumes as used
in the processing of the samples. The reagent blank must be carried through the
complete procedure and must contain the same acid concentration in the final solution
as in the sample solution used for analysis.
7.6 In addition to the calibration standards, an instrument check standard (3.7), an interference
check sample (3.8), and a quality control sample (3.9) are also required for the analyses.
7.6.1 The instrument check standard is prepared by the analyst by combining compatible
elements at a concentration equivalent to the midpoint of their respective calibration
curves. (See Section 12.1.1.)
7.6.2 The interference check sample is prepared by the analyst in the following manner.
Select a representative sample which contains minimal concentrations of the analytes
of interest but a known concentration of interfering elements that will provide an
adequate test of the correction factors. Spike the sample with the elements of
interest at the approximate concentration of either 100 /ug/L or 5 times the estimated
detection limits given in Table B-1. (For effluent samples of expected high concentra-
tions, spike at an appropriate level.) If the type of samples analyzed are varied, a
synthetically prepared sample may be used if the above criteria and intent are met.
A limited supply of a synthetic interference check sample will be available from the
Quality Assurance Branch of EMSL-Cincinnati. (See Section 12.1.2.)
7.6.3 The quality control sample should be prepared in the same acid matrix as the
calibration standards at a concentration near 1 mg/L and in accordance with the
instructions provided by the supplier. The Quality Assurance Branch of EMSL-
Cincinnati will either supply a quality control sample or information where one of
equal quality can be procured. (See Section 12.1.3.)
8 Sample Handling and Preservation
8.1 For the determination of trace elements, contamination and loss are of prime concern.
Dust in the laboratory environment, impurities in reagents and impurities on laboratory
apparatus which the sample contacts are all sources of potential contamination. Sample
containers can introduce either positive or negative errors in the measure ment of trace
elements by (a) contributing contaminants through leaching or surface desorption and (b)
by depleting concentrations through adsorption. Thus the collection and treatment of the
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sample prior to analysis requires particular attention. Laboratory glassware including the
sample bottle (whether polyethylene, polypropylene or FEP-fluorocarbon) should be
thoroughly washed with detergent and tap water; rinsed with (1+1) nitric acid, tap water,
(1+1) hydrochloric acid, tap and finally deionized, distilled water in that order (See Notes
2 and 3).
NOTE 2: Chromic acid may be useful to remove organic deposits from glassware; however, the
analyst should be cautioned that the glassware must be thoroughly rinsed with water to
remove the last traces of chromium. This is especially important if chromium is to be
included in the analytical scheme. A commercial product, NOCHROMIX, available from
Godax Laboratories, 6 Varick St., New York, NY 10013, may be used in place of chromic
acid. Chromic acid should not be used with plastic bottles.
NOTE 3: If it can be documented through an active analytical quality control program using spiked
samples and reagent blanks that certain steps in the cleaning procedure are not required
for routine samples, those steps may be eliminated from the procedure.
8.2 Before collection of the sample, a decision must be made as to the type of data desired,
i.e., is dissolved, suspended, or total, so that the appropriate preservation and
pretreatment steps may be accomplished. Filtration, acid preservation, etc., are to be
performed at the time the sample is collected or as soon as possible thereafter.
8.2.1 For the determination of dissolved elements, the sample must be filtered through a
0.45-pn membrane filter as soon as practical after collection. (Glass or plastic
filtering apparatus are recommended to avoid possible contamination.) Use the first
50-100 mL to rinse the filter flask. Discard this portion and collect the required volume
of filtrate. Acidify the filtrate with (1+1) HNO3 to a pH of 2 or less. Normally, 3 mL of
(1+1) acid per liter should be sufficient to preserve sample.
8.2.2 For the determination of suspended elements, a measured volume of unpreserved
sample must be filtered through a 0.45-/L/m membrane filter as soon as practical after
collection. The filter plus suspended material should be transferred to a suitable
container for storage and shipment. No preservative is required.
8.2.3 For the determination of total or total recoverable elements, the sample is acidified
with (1+1) HNO3 to pH 2 or less as soon as possible, preferably at the time of
collection. The sample is not filtered before processing.
9 Sample Preparation
9.1 For the determinations of dissolved elements, the filtered, preserved sample may often be
analyzed as received. The acid matrix and concentration of the samples and calibration
standards must be the same. (See Note 6.) If a precipitate formed upon acidification of
the sample or during transit or storage, it must be redissolved before the analysis by
adding additional acid or by heat (as described in 9.3), or both.
9.2 For the determination of suspended elements, transfer the membrane filter containing the
insoluble material to a 150-mL Griffin beaker and add 4 mL concentrated HNO3. Cover
the beaker with a watch glass and heat gently. The warm acid will soon dissolve the
membrane. Increase the temperature of the hot plate and digest the material. When the
acid has nearly evaporated, cool the beaker and watch glass and add another 3 mL of
concentrated HNO3. Cover and continue heating until the digestion is complete; digestion
-------
Appendix B
Revision 2
Date: 2/87
Page 12 of 16
is generally indicated by a light colored digestate. Evaporate to near dryness (2 ml),
cool, add 10 mL HCI (1+1) and 15 ml deionized, distilled water per 100 mL dilution, and
warm the beaker gently for 15 minutes to dissolve any precipitate or residue. Allow to
cool, wash down the watch glass and beaker walls with deionized distilled water, and
filter the sample to remove insoluble material that could clog the nebulizer. (See Note 4.)
Adjust the volume based on the expected concentrations of elements present. This
volume will vary depending on the elements to be determined (See Note 6). The sample
is now ready for analysis. Concentrations so determined shall be reported as "sus-
pended."
NOTE 4: In place of filtering, the sample after diluting and mixing may be centrifuged or allowed
to settle by gravity overnight to remove insoluble material.
9.3 For the determination of total elements, choose a measured volume of the well-mixed,
acid-preserved sample appropriate for the expected level of elements and transfer it to a
Griffin beaker. (See Note 5.) Add 3 mL of concentrated HNO3. Place the beaker on a
hot plate and evaporate to near dryness cautiously, making certain that the sample does
not boil and that no area of the bottom of the beaker is allowed to go dry. Cool the
beaker and add another 5 ml portion of concentrated HNO3. Cover the beaker with a
watch glass and return it to the hot plate. Increase the temperature of the hot plate so
that a gentle reflux action occurs. Continue heating, adding additional acid as necessary,
until the digestion is complete (generally indicated when the digestate is light in color or
does not change in appearance with continued refluxing.) Again, evaporate to near
dryness and cool the beaker. Add 10 mL of (1+1) HCI and 15 mL of deionized, distilled
water per 100 mL of final solution and warm the beaker gently for 15 min. to dissolve any
precipitate or residue resulting from evaporation. Allow to cool; wash down the beaker
walls and watch glass with deionized distilled water and filter the sample to remove in-
soluble material that could clog the nebulizer. (See Note 4.) Adjust the sample to a
predetermined volume based on the expected concentrations of elements present. The
sample is now ready for analysis (See Note 6). Concentrations so determined shall be
reported as "total."
NOTE 5: If low determinations of boron are critical, quartz glassware should be used.
NOTE 6: If the sample analysis solution has a different acid concentration from that given in 9.4
but does not introduce a physical interference or affect the analytical result the same
calibration standards may be used.
9.4 For the determination of total recoverable elements, choose a measured volume of a well-
mixed, acid-preserved sample appropriate for the expected level of elements and transfer
it to a Griffin beaker. (See Note 5.) Add 2 mL of (1 + 1) HN03 and 10 mL of (1+1) HCI to
the sample and heat on a steam bath or hot plate until the volume has been reduced to
near 25 mL making certain the sample does not boil. After this treatment, cool the sample
and filter to remove insoluble material that could clog the nebulizer. (See Note 4.) Adjust
the volume to 100 mL and mix. The sample is now ready for analysis. Concentrations so
determined shall be reported as "total."
10 Procedure
10.1 Set up instrument with proper operating parameters as established in Section 6.2. The
instrument must be allowed to become thermally stable before analysis begins. This
usually requires at least 30 min. of operation prior to calibration.
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Appendix B
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Page 13 of 16
10.2 Initiate appropriate operating configuration of computer.
10.3 Profile and calibrate instrument according to recommended procedures of the manufac-
turer, using the typical mixed calibration standard solutions described in Section 7.4.
Flush the system with the calibration blank (7.5.1) between each standard. (See Note 7.)
(The use of the average intensity of multiple exposures for both standardization and
sample analysis has been found to reduce random error.)
NOTE 7: For boron concentrations greater than 500 pg/L, extended flush times of 1 to 2 minutes
may be required.
10.4 Before beginning the sample run, reanalyze the highest mixed calibration standard as if
it were a sample. Concentration values obtained should not deviate from the actual
values by more than ±5 percent (or the established control limits, whichever is lower). If
they do, follow the recommendations of the instrument manufacturer to correct for this
condition.
10.5 Begin the sample run, flushing the system with the calibration blank solution (7.5.1)
between each sample. (See Note 7.) Analyze the instrument check standard (7.6.1) and
the calibration blank (7.5.1) after each 10 samples.
10.6 If it has been found that methods of standard addition are required, the following
procedure is recommended.
10.6.1 The standard addition technique (14.2) involves preparing new standards in the
sample matrix by adding known amounts of standard to one or more aliquots of the
processed sample solution. This technique compensates for a sample constituent
that enhances or depresses the analyte signal and thus produces a different slope
from that of the calibration standards. It will not correct for additive interference
which causes a baseline shift. The simplest version of this technique is the single-
addition method. The procedure is as follows. Two identical aliquots of the sample
solution, each of volume Vx, are taken. To the first (labeled A) is added a small
volume V, of a standard analyte solution of concentration cs. To the second (labeled
B) is added the same volume V. of the solvent. The analytical signals of A and B
are measured and corrected for nonanalyte signals. The unknown sample concentra-
tion cx is calculated:
SbVC.
(S. - SJ Vx
Where SA and SB are the analytical signals (corrected for the blank) of solutions A
and B, respectively. V, and c, should be chosen so that SA is roughly twice SB on
the average. It is best if V, is made much less than Vx, and thus c, is much greater
than cx. If a concentration step is used, the additions are best made first and
carried through the entire procedure. For the results from this technique to be valid,
the following limitations must be taken into consideration:
1. The analytical curve must be linear.
2. The chemical form of the analyte added must respond the same as the analyte in
the sample.
3. The interference effect must be constant over the working range of concern.
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Appendix B
Revision 2
Date: 2/87
Page 14 of 16
4. The signal must be corrected for any additive interference.
11 Calculation
11.1 Reagent blanks (7.5.2) should be subtracted from all samples. This is particularly
important for digested samples requiring large quantities of acids to complete the
digestion.
11.2 If dilutions were performed, the appropriate factor must be applied to sample values.
11.3 Data should be rounded to the thousandth place, and all results should be reported in
mg/L up to three significant figures.
12 Quality Control (Instrument)
12.1 Check the instrument standardization by analyzing appropriate quality control check
standards as follow:
12.1.1 Analyze an appropriate instrument check standard (7.6.1) containing the elements of
interest at a frequency of 10%. This check standard is used to determine instrument
drift. If agreement is not within ±5% of the expected values or within the estab-
lished control limits, whichever is lower, the analysis is out of control. The analysis
should be terminated, the problem corrected, and the instrument recalibrated. Analyze
the calibration blank (7.5.1) at a frequency of 10%. The result should be within the
established control limits of 2 standard deviations of the mean value. If not, repeat
the analysis two more times and average the three results. If the average is not
within the control limit, terminate the analysis, correct the problem, and recalibrate
the instrument.
12.1.2 To verify interelement and background correction factors, analyze the interference
check sample (7.6.2) at the beginning, end, and at periodic intervals throughout the
sample run. Results should fall within the established control limits of 1.5 times the
standard deviation of the mean value. If not, terminate the analysis, correct the
problem, and recalibrate the instrument.
12.1.3 A quality control sample (7.6.3) obtained from an outside source must first be used
for the initial verification of the calibration standards. A fresh dilution of this sample
shall be analyzed every week thereafter to monitor the instrument stability. If the
results are not within ±5% of the true value listed for the control sample, prepare a
new calibration standard and recalibrate the instrument. If this does not correct the
problem, prepare a new stock standard and a new calibration standard and repeat
the calibration.
13 Precision and Accuracy
13.1 In an EPA round-robin phase 1 study, seven laboratories applied the ICP technique to
acid-distilled water matrices that had been dosed with various metal concentrates. Table
B-4 lists the true value, the mean reported value, and the mean % relative standard
deviation.
-------
Table B-4. ICP Precision and Accuracy Data
Appendix B
Revision 2
Date: 2/87
Page 15 of 16
Element
Sample 1
Mean
True Reported Mean
Value Value Percent
pg/L RSD
Sample 2
Mean
True Reported Mean
Value Value Percent
/jg/L RSD
Sample 3
Mean
True Reported Mean
Value Value Percent
pg/L fjg/L RSD
Be
Mn
V
As
Cr
Cu
Fe
Al
Cd
Co
Ni
Pb
Zn
Se
750
350
750
200
150
250
600
700
50
500
250
250
200
40
733
345
749
208
149
235
594
696
48
512
245
236
201
32
6.2
2.7
1.8
7.5
3.8
5.1
3.0
5.6
12
10
5.8
16
5.6
21.9
20
15
70
22
10
11
20
60
2.5
20
30
24
16
6
20
15
69
19
10
11
19
62
2.9
20
28
30
19
8.5
9.8
6.7
2.9
23
18
40
15
33
16
4.1
11
32
45
42
180
100
170
60
50
70
180
160
14
120
60
80
80
10
176
99
169
63
50
67
178
161
13
108
55
80
82
8.5
5.2
3.3
1.1
17
3.3
7.9
6.0
13
16
21
14
14
9.4
8.3
Not all elements were analyzed by all laboratories.
14 References
14.1 Winge, R.K., V.J. Peterson, and VA Fassel, Inductively Coupled Plasma-Atomic Emission
Spectroscopy: Prominent Lines, EPA/600/479-017.
14.2 Winefordner, J.D., "Trace Analysis: Spectroscopic Methods for Elements," Chemical
Analysis Vol. 46 pp. 41-42.
14.3 Handbook for Analytical Quality Control in Water and Wastewater Laboratories,
EPA/600/4-79-019.
14.4 Garbarino, J.R., and Taylor, H.E., "An Inductively-Coupled Plasma Atomic Emission
Spectrometric Method for Routine Water Quality Testing," Applied Spectroscopy 33
No. 3(1979).
14.5 Methods for Chemical Analysis of Water and Wastes," EPA/600/4-79-020.
14.6 Annual Book of ASTM Standards, Part 31.
14.7 Carcinogens - Working With Carcinogens, Department of Health, Education, and Welfare,
Public Health Service, Center for Disease Control, National Institute for Occupational
Safety and Health, Publication No. 77-206, Aug. 1977.
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Appendix B
Revision 2
Date: 2/87
Page 16 of 16
14.8 OSHA Safety and Health Standards, General Industry, (29CFR 1910), Occupational Safety
and Health Administration, OSHA 2206, (Revised, January 1976).
14.9 Safety in Academic Chemistry Laboratories, American Chemical Society Publication,
Committee on Chemical Safety, 3rd Edition, 1979.
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Appendix C
Revision 2
Date: 12/86
Page 1 of 62
Appendix C
Forms for Reporting Analytical Laboratory Data
The following forms are used for recording raw data and results form the analytical
procedures detailed in Section 3 through 16.
An index of data forms is presented as Table 2-5. Form 102 is a shipping form that is used
to confirm sample shipment and receipt. Forms 103a and 103b summarize pH, moisture, and
particle size analysis results. Forms 109 through 114 contain quality control data. The 200-series
forms summarize data that are corrected for both blanks and dilutions. Raw data are recorded on
forms 115, 116, 303b, 306, and 308.
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Appendix C
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Page 2 of 62
NATIONAL ACID DEPOSITION SOIL SURVEY (NADSS)
SHIPPING FORM 102
DATE RECEIVED
BY DATA MGT.
IT "IT ~H~ ~B~ '
Prep Lab ID Date Received
Batch ]
Analytl
Sample
Number
01
OZ
03
04
05
06
07
08
09
10
11
1Z
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Z7
28
29
3D
31
32
33
34
35
36
37
38
39
40
41
42
D D M M M Y Y
D Date Shipped
cal Lab ID
Sample
(Identify By Check)
Shipped Received
Soil Type
(Identify By Check)
Organic Mineral
signature of Preparation Laboratory nan
Cements :
Inorganic
Carbon
t - Yes
N - No
ROCk
Fragments
Shipped
Check 1f Yes
iger:
Hnlte - SMO Canary - Analytical Pink - Analytical sola - Analytical
with copy to sno nth copy to EHSL-LV Lab
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Appendix C
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Page 3 of 62
SUMMARY OF pH AND MOISTURE DATA
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 103a
Analytical Lab ID Lab Manager's Signature
Batch ID Date Forn Completed
Prep Lab Mane Date Batch Received
Remarks
Sample
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
IB
19
ZO
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
pH
In H20
pH
In 0.01M
CaCl2
PH
In 0.002M
CaClj
Moisture.
Height
1
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Appendix C
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Page 4 of 62
PARTICLE SIZE ANALYSIS DATA
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 103b
Analytical Lab 10 Lab Manager's Signature
Batch ID __^^______________ Oat« T°rm Completed
Prep Lab Name Date Batch Received
Remarks ___^_
Particle Size Analysis, Height I
Size Class and Particle Diameter (mm)
Sample
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
ZO
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36 ""
37
38
39
40
41
42
Sand
(2.0-
0.05)
Silt
(0.05-
0.002)
Clay
(<0.002)
Sand
Very
Coarse
(2.0-
1.0)
Coarse
(1.0-
0.5)
Medium
(0.5-
0.25)
Fine
(0.25-
0.1)
Very Fine
(0.1-
0.05)
511 1
Coarse
(0.05-
0.02)
Fine
(0.02-
0.002)
-------
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 109a
QUALITY CONTROL: DETECTION LIMITS
Appendix C
Revision 2
Date: 12/86
Page 5 of 62
LAB NAME
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Reporting Contract-Required
Units Detection Limit
Instrumental
Detection Date Determined
Limit (DD MMM YY)
Total S wt. %
Total N wt. %
Total C wt. %
Inorganic C wt. %
CEC (FIA) meq/100 g
CEC (titration) meq/100 g
Exchangeable Acidity:
BaCl2-TEA meq/100 g
KC1 meq/100 g
KC1-A13+ meq/100 g
0.010%
0.010%
0.010%
0.010%
0.140 mg N/L
0.010 meq NH4+*
0.40 meq*
0.25 meq*
0.10 mg/L
*For titrations, the instrumental detection limit is a calculated value based
upon a minimum titration.
-------
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 109b
QUALITY CONTROL: DETECTION LIMITS
BATCH ID
Appendix C
Revision 2
Date: 12/86
Page 6 of 62
LAB MANAGER'S SIGNATURE
Calculated Contract-Required Instrumental
Reporting Instrumental Detection Date Determined
Parameter Units Detection Limit Limit (DD MMM YY)
NH/iOAc Extract
Ca2+
Mg2+
K+
Na+
NH4C1 Extract:
Ca2+
Mg2+
K+
Na+
0.002 M CaCl2
Ca2+
Mg2+
K+
Na+
Fe3+
A13+
meq/100 g
meq/100 g
meq/100 g
meq/100 g
meq/100 g
meq/100 g
meq/100 g
meq/100 g
Extract:
meq/100 g
meq/100 g
meq/100 g
meq/100 g
meq/100 g
meq/100 g
0.050 mg/L
0.020 mg/L
0.020 mg/L
0.020 mg/L
0.050 mg/L
0.020 mg/L
0.020 mg/L
0.020 mg/L
— *
0.020 mg/L
0.020 mg/L
0.020 mg/L
0.050 mg/L
0.050 mg/L
'Report the standard deviation of 10 non-consecutive blank analyses.
-------
Appendix C
Revision 2
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Page 7 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 109c
QUALITY CONTROL: DETECTION LIMITS
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Calculated Contract-Required
Reporting Instrumental
Units Detection Limit
Instrumental
Detection Date Determined
Limit (DD MMM YY) .
Adsorption mg S/L
S0|- (H20
extract)
NOj (H20
extract)
soj- (PO$-
extract)
mg S/Kg
mg N/Kg
mg S/Kg
Pyrophosphate Extract;
wt. %
wt. %
A13+
Acid-Oxalate Extract;
wt. %
wt. %
A13+
Citrate-Dithionite Extract:
Fe3+
Al3+
wt. %
wt. %
0.10 mg SO|"/L
0.1 mg SO|"/L
0.10 mg N05/L
0.10 mg SOj"/L
0.50 mg/L
0.50 mg/L
0.50 mg/L
0.50 mg/L
0.50 mg/L
0.50 mg/L
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Appendix C
Revision 2
Date: 12/86
Page 8 of 62
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM UOt
QUALITY CONTROL: MATRIX SPIKES
LAB NAME ___________
LAB MANAGER'S SIMATUW
BATCH ID
Eitractant
Parameter
1.0 N NH«OAc
Ca.
•«/L
First Matrix
Spike Simple ID:
Sample Result
Spfte Result
Spike Added
S Recovery
Second Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
S Recovery
TnlnnfttrTr
Spike Sample 10:
Sample Result
Spike Result
Spike Added
S Recovery
««.
•I/I
K.
•I/I
N*.
•9/L
1.0 M NH4C1
Ca.
•9/L
H9.
•9/L
K.
•9/L
Na.
•9/L
0.002 M CaCl2
Ca.
•9/L
"9.
•9/L
K.
•9/L
Na,
•9/L
Fe.
•g/L
Al.
•9/L
NONE
CEC
NH4«,_
•CEC units are Instruwnt
dlstlllatlon/tltratlon.
•nd -fthod dependent: Fill in «g N/L for flow Injection analysis or men 'or
-------
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM HOb
QUALITY CONTROL: MATRIX SPIKES
LAB MANAGER'S SIGNATURE
LAB NAME
BATCH ID
Appendix C
Revision 2
Date: 12/86
Page 9 of 62
Extractant
Parameter
Pyrophosphate
Fe,
mg/L
Al,
mg/L
Acid-
Oxalate
Fe,
mg/L
Al,
mg/L
C1 trate-
Dithionite
Fe,
mg/L
Al,
mg/L
KC1
Al,
mg/L
First Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
Second Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
Third Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
-------
Appendix C
Revision 2
Date: 12/86
Page 10 of 62
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM llObb
QUALITY CONTROL: MATRIX SPIKES
LAB MANAGER'S SIGNATURE
LAB NAME
BATCH ID
Extractant
Parameter
Deionized
H20
NO;
mg/L
so?-,
mg/L
500 mg P/L
so?-,
mg/L
First Matrix
Spike Sample ID
Sample Result
Spike Result
Spike Added
% Recovery
Second Matrix
Spike Sample ID
Sample Result
Spike Result
Spike Added
% Recovery
Third Matrix
Spike Sample ID
Sample Result
Spike Result
Spike Added
% Recovery
-------
Appendix C
Revision 2
Date: 12/86
Page 11 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM llOc
QUALITY CONTROL: MATRIX SPIKES
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Total S,
Weight %
Total N,
Weight %
Total C,
Weight %
Inorganic C,
Weight %
<2 mm J2-20 mm
First Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
Second Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
Third Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
-------
Appendix C
Revision 2
Date: 12/86
Page 12 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM llOd
QUALITY CONTROL: MATRIX SPIKES
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Sulfate remaining in solution, mg S/L
Initial solution concentration, mg S/L
0
2
4
8
16
32
First Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
Second Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
Third Matrix
Spike Sample ID:
Sample Result
Spike Result
Spike Added
% Recovery
-------
Appendix C
Revision 2
Date: 12/86
Page 13 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM Ilia
QUALITY CONTROL: REPLICATES
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Triplicate
Sample ID:
First Replicate
Result
Second Replicate
Result
Third Replicate
Result
Average
Standard Deviation
% RSD
PH
in H20
NA
PH
in 0.01 M
CaCl2
NA
PH
in 0.002 M
CaCl2
NA
Specific
Surface,
m2/g
NA
-------
Appendix C
Revision 2
Date: 12/86
Page 14 of 62
LAB NAME
DIRECT/DELAYED RESPOKSE PROJECT (DDRP) SOIL SURVEY
FORM lllb
QUALITY CONTROL: REPLICATES
BATCH ID
LAB MANAGER'S SIGNATURE
Particle Size Analysis. Height X
Size Class and Particle Diameter (mm)
Parameter
Sand
(2.0-
0.05)
Silt
(0.05-
0.002)
Clay
(<0.002)
Sand
Very
Coarse
(2.0-
1.0)
Coarse
(1.0-
0.5)
Medium
(0.5-
0.25)
Fine
(0.25-
0.1)
Very
Fine
(0.1-
0.05)
Silt
Coarse
(0.05-
0.02)
Fine
(0.02-
0.002)
Duplicate
Sample ID:
Sample
Result
Duplicate
Results
I RSD
Second Duplicate
Sample ID:
Sample
Result
Duplicate
Result
1 RSD
Third Duplicate
Sample ID:
Sample
Result
Duplicate
Result
I RSD
-------
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM lllc
QUALITY CONTROL: REPLICATES
BATCH ID
LAB MANAGER'S SIGNATURE
Appendix C
Revision 2
Date: 12/86
Page 15 of 62
Extractant
Parameter
1.0 M NH*OAC
ca,
me q/ 100 g
Mg,
me q/ 100 g
K.
me q/ 100 g
Na,
me q/ 100 g
CEC,
me q/ 100 g
Duplicate
Sample ID:
Sample Result
Duplicate
Result
% RSD
Second Duplicate
Sample ID:
Sample Result
Duplicate
Result
% RSD
Third Duplicate
Sample ID:
Sample Result
Duplicate
Result
% RSD
-------
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM Hid
QUALITY CONTROL: REPLICATES
BATCH ID
LAB MANAGER'S SIGNATURE
Appendix C
Revision 2
Date: 12/86
Page 16 of 62
Extractant
Parameter
1.0 M NH4C1
Ca,
meq/100 g
Mg,
meq/100 g
K,
meq/100 g
Na,
meq/100 g
CEC,
meq/100 g
Duplicate
Sample ID:
Sample Result
Duplicate
Result
% RSD
Second Duplicate
Sample ID:
Sample Result
Duplicate
Result
% RSD
Third Duplicate
Sample ID:
Sample Result
Duplicate
Result
% RSD
-------
Appendix C
Revision 2
Date: 12/86
Page 17 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM llle
QUALITY CONTROL: REPLICATES
BATCH ID
LAB MANAGER'S SIGNATURE
Extractant
Parameter
0.002 M C3C12
Ca,
meq/100 g
Mg,
meq/100 g
K,
meq/100 g
Na,
meq/100 g
Fe,
meq/100 g
Al,
meq/100 g
Duplicate
Sample ID:
Sample
Result
Duplicate
Result
% RSD
Second
Duplicate
Sample ID:
Sample
Result
Duplicate
Result
% RSD
Third
Duplicate
Sample ID:
Sample
Result
Duplicate
Result
% RSD
-------
Appendix C
Revision 2
Date: 12/86
Page 18 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM lllf
QUALITY CONTROL: REPLICATES
BATCH ID
LAB MANAGER'S SIGNATURE
Extract
Parameter
Pyrophosphate
Fe
Weight Z
Al.
Weight %
Acid-uxaiate
Fe,
Weight %
Al,
Weight %
Citrate-Dithionite
Fe,
Weight %
Al,
Weight %
Duplicate
Sample ID:
Sample Result
Duplicate
Result
Z RSD
Second
Duplicate
Sample ID:
Sample Result
Duplicate
Result
% RSD
Third
Duplicate
Sample ID:
Sample Result
Duplicate
Result
% RSD
-------
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 11lg
QUALITY CONTROL: REPLICATES
Appendix C
Revision 2
Date: 12/86
Page 19 of 62
LAB NAME
BATCH ID
LAB MANAGER'S SIGNATURE
Extract
Extractabie Nitrate.
mg N/kg
H£0
Extractable Sulfate.
mg S/kg
H20
P04
Exchangeable Acidity,
neq/100 g
BaClj
KC1
Extractable Al .
•eq/100 g
KC1
Duplicate
Sample ID:
Sample Result
Duplicate
Result
t RSD
Second
Duplicate
Sample ID:
Sample Result
Duplicate
Result
1 RSD
Third
Duplicate
Sample ID:
Sample Result
Duplicate
Result
I RSD
-------
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM lllh
QUALITY CONTROL: REPLICATES
Appendix C
Revision 2
Date: 12/86
Page 20 of 62
LAB NAME
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Sulfate Remaining in Solution, mg 5/L
Initial Solution Concentration, mg S/L
0
2
4
8
16
32
Duplicate
Sample ID:
Sample
Result
Duplicate
Result
I RSD
Second Duplicate
Sample ID: . H „
Sample
Result
Duplicate
Result
% RSD
.' '"f ' :
••'t 4.
Third Duplicate , ,,.:.>
Sample ID: r "Sv
Sampl e
Result
Duplicate
Result
Z RSD
-------
Appendix C
Revision 2
Date: 12/86
Page 21 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 1111
QUALITY CONTROL: REPLICATES
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Total
s,
Weight Z
Total
N,
Weight %
Total
C,
Weight %
inorganic C,
Weight %
<2 mm I 2-20 mm
Duplicate
Sample ID:
Sampl e
Result
Duplicate
Result
% RSD
Second Duplicate
Sample ID: ;
Sampl e
Result
Duplicate
Result
% RSD
~*~%
- •'&
,?/•"
r^f;
-'. '. • * ' * jf\
•.,;< .,-.-,
Third Duplicate
Sample ID:
Sampl e
Result
Duplicate
Result
% RSD
-------
Appendix C
Revision 2
Date: 12/86
Page 22 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 112a
QUALITY CONTROL: BLANKS AND QCCS
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Reagent Blank*
DL Theoretical
QCCS Measured
Low QCCS
True Value
Low QCCS
Upper Limit
Low QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Upper Limit
High QCCS
Lower Limit
Initial
Continuing
Continuing
Final
PH
in H20
NA
NA
PH
in 0.01M
CaCl2
NA
NA
PH
in 0.002M
CaCl£
NA
NA
^Reagent blank is the solution being added to the soil
-------
Appendix C
Revision 2
Date: 12/86
Page 23 of 62
LAB KAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 112b
QUALITY CONTROL: BLANKS AND QCCS
BATCH ID
LAB MANAGER'S SIGNATURE
Particle Size Analysis, Weight 1
Size Class and Particle Diameter (mm)
Parameter
Reagent
Blank
DL QCCS
Theoretical
Measured
Low QCCS
True Value
Low QCCS
Upper Li mil
Low QCCS
Lower Limii
Initial
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Upper Limit
High QCCS
Lower Limii
Initial
Continuing
Continuing
^inal
Sand
(2.0-
0.05}
NA
NA
NA
Silt
(0.05-
0.002)
NA
NA
NA
Clay
(<0.002)
NA
NA
Sand
Very
Coarse
(2.0-
1.0)
NA
NA
NA
Coarse
(1.0-
0.5)
NA
NA
NA
Medium
(0.5-
0.25)
NA
NA
NA
Fine
(0.25-
0.1)
NA
NA
NA
Very
Fine
(0.1-
0.05)
NA
NA
NA
Silt
Coarse
(0.05-
0.02)
NA
NA
NA
Fine
(0.02-
0.002)
NA
NA
NA
-------
Appendix C
Revision 2
Date: 12/86
Page 24 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 112c
QUALITY CONTROL: BLANKS AND QCCS
BATCH ID
LAB MANAGER'S SIGNATURE
Extractant
Parameter
Calibration
Blank
Reagent Blank 1
Reagent Blank 2
Reagent Blank 3
DL Theoretical
QCCS Measured
Low QCCS
True Value
Low QCCS
Upper Limit
Low QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Upper Limit
High QCCS
Lower Limit
Initial
Continuing
Continuing
Final
1.0 M NH4OAc
Ca,
mg/L
Mg,
mg/L
K,
mg/L
Na,
mg/L
CEC,
*
1.0 M NH4C1
Ca,
mg/L
Mg,
mg/L
K,
mg/L
Na,
mg/L
CEC,
*
*CEC reporting units are instrument and method dependent. Fill in mg N/L for
flow injection analysis or meq for distillation/titration.
-------
Appendix C
Revision 2
Date: 12/86
Page 25 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 112d
QUALITY CONTROL: BLANKS AND QCCS
BATCH ID LAB MANAGER'S SIGNATURE
Extractant
Parameter
Calibration
Blank
Reagent Blank*
DL (Theoretical
QCCSJMeasured
Low (icCS
True Value
Low QCCS
Upper Limit
Low QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Upper Limit
High QCCS
Lower Limit
Initial
Continuing
Continuing
Final
0.002 M CaCl2
Ca,
mg/L
Mg,
mg/L
K,
mg/L
Na,
mg/L
Fe,
mg/L
Al,
mg/L
*Analyze 0.002 M CaCl2 solution that has been extracted through filter pulp.
-------
Appendix C
Revision 2
Date: 12/86
Page 26 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM U2e
QUALITY CONTROL: BLANKS AND QCCS
BATCH ID
LAB MANAGER'S SIGNATURE
Extractant
Parameter
Calibration
Blank
Reagent Blank
DL Theoretical
QCCS Measured
Low O.CCS
True Value
Low QCCS
Upper Limit
Low QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Upper Limit
High QCCS
Lower Limit
Initial
Continuing
Continuing
Final
Pyrophosphate
Fe,
mg/L
Al,
mg/L
Acid-Oxalate
Fe,
mg/L
Al,
mg/L
Citrate-Dithionite
Fe,
mg/L
Al,
mg/L
-------
Appendix C
Revision 2
Date: 12/86
Page 27 of 62
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 112f
QUALITY COKTROL: BLANKS AND QCCS
LAB NAME
BATCH ID
LAB NANAGER'S SIGNATURE
Parameter
Extractant
Calibration
Blank
Reagent Blank l*
Reagent Blank 2
Reagent Blank 3
DL (Theoretical
QCCS (Measured
Low QCCS
True Value
Low QCCS
Upper Limit
Low QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Upper Limit
High QCCS
Lower Limit
Initial
Continuing
Continuing
Final
Cxtractable Nitrate.
mg/L
H20
NA
NA
Extractable SuHate,
•g/L
KzO
NA
NA
roj-
NA
NA
Exchangeable Acidity.
meg
Bad 2
NA
NA
NA
KC1
NA
NA
NA
Extr actable Al.
«g/L
KC1
•Reagent blank is the extracting solution.
-------
Appendix C
Revision 2
Date: 12/86
Page 28 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 112g
QUALITY CONTROL: BLANKS AND QCCS
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Calibration
Blank
Reagent Blank
DL Theoretical
QCCS Measured
Low QCCS
True Value
Low QCCS
Upper Limit
Low QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Upper Limit
High QCCS
Lower Limit
Initial
Continuing
Continuing
Final
Total
s,
Weight %
NA
Total
N,
Weight %
K
Factor
MV/ug
NA
NA
Total
c,
Weight %
K
Factor
uV/M9
NA
NA
Inorganic C,
Weight Z
<2 mm
2-20 mm
-------
Appendix C
Revision 2
Date: 12/86
Page 29 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM 112h
QUALITY CONTROL: BLANKS AND QCCS
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Low QCCS
True Value
Low QCCS
Upper Limit
Low QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Final
Specific
Surface, m^/g
(at equilibrium)
•Measurements may be taken less frequen
day actually performed.
Day*
0
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
28
Weight of LGME In mg
Blank 1
Blank 2
Blank 3
ly than daily, but record the results on the
-------
Appendix C
Revision 2
Date: 12/86
Page 30 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 1121
QUALITY CONTROL: BLANKS AND QCCS
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Reagent Blank
LOW QCCS
True Value
Low QCCS
Upper Limit
Low QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS
Upper Limit
High QCCS
Lower Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Continuing
Final
Sulfate remaining in solution, mg S/L
Initial so
0
2
N/A
ution concentration, mg S/L
4
N/A
8
N/A
16
N/A
32
N/A
-------
Appendix C
Revision 2
Date: 12/86
Page 31 of 62
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 113
QUALITY CONTROL: ION CHROMATOGRAPHY RESOLUTION TEST
LAB NAME __
BATCH ID
LAB MANAGER'S SIGNATURE BAIL OK ANALYSIS ~~~
MM/DD/YR
1C Make and Model:
Concentration Peak Area Peak Height
(mg/L) (integrator units) (cm)
Column Back Pressure (at max. of stroke): psi
Flow Rate: nt/min
Column Model: Date of Purchase:_
Column Manufacturer:
Column Serial No:
Precolumn 1n system Yes No
*100 x 2(tr2-tr1)/(H1+W2) N03 - P04
Percentage Resolution: 100 x 2(tr3-tr2)/(w2+H3) P04 - S04
100 x 2(tr3-tri)/(w1+H3) N03 - S04
reater than 601.
The resolution must be greater
Test Chromatogram:
(FACSIMILE)
•Calculations may change 1f order of elutlon 1s different from test chrotnatogram.
-------
Appendix C
Revision 2
Date: 12/86
Page 32 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 114a
QUALITY CONTROL: STANDARD ADDITIONS
BATCH ID
LAB MANAGER'S SIGNATURE
Extract
Parameter
1.0 M NH4OAc
Ca,
mg/L
Mg,
mg/L
K,
mg/L
Na,
mg/L
1.0 M NH4C1
Ca,
mg/L
Mg,
mg/L
K,
mg/L
Na,
mg/L
Original
Sample ID:
Single
Response
Spike Added
Concen-
tration
Sampl e
Spike 1
Response
Spike 2
Concen-
tration
Sampl e
Spike 2
Response
Sample Con-
centration
for Original
Sampl e
(calc.)
-------
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 1Mb
QUALITY CONTROL: STANDARD ADDITIONS
BATCH ID LAB MANAGER'S SIGNATURE
Extract
Parameter
0.002 M CaCl2
Ca.
mg/L
Mg.
mg/L
K.
mg/L
Na.
mg/L
Fe.
mg/L
A1.
mg/L
Pyrophosphate
Fe.
mg/L
Al.
mg/L
Acld-Oxalate
Fe,
mg/L
Al.
••g/L
Citrate-
Dithlonlte
Fe.
mg/L
Al.
mg/L
Original
Sample ID:
Single
Response
Spike Added
Concentration
Sample
Spike 1
Response
Spike 2
Concentration
Sample
Spike 2
Response
Sample
Concentration
for Original
Sample (calc.)
Q> B) (D T}
•8 » £*
w _^ 5' Q_
0
-*o>
CO
ro
-------
Appendix C
Revision 2
Date: 12/86
Page 34 of 62
LAB NAME
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 114c
QUALITY CONTROL: STANDARD ADDITIONS
BATCH ID
LAB MANAGER'S SIGNATURE
Extract
Parameter
"2°
S04~
mg7L
P0^~
S04~
»g/L
KCl
Al
ng/L
None
SO?'
•g/L
Solid
Total
s.
wt I
Total
N.
wt S
Total
C,
wt I
Inorganic C,
wtt
<2mn
2-20mm
Original
Sample ID:
Single
Response
Spike Added
Concentra-
tion
Sampl e
Spike 1
Response
Spike 2
Concentra-
tion
Sampl e
Spike 2
Response
Sample
Concentratio
for Original
Sample
(calc.)
i
-------
Appendix C
Revision 2
Date: 12/86
Page 35 of 62
AIR DRY SAMPLE HEIGHT IN GRAMS
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM U5a
Lab Name
Batch ID
Lab Manager's Signature
Sample
Number
01
02
03
04
05
06
"07 '
os
09
10
11 "
' 12
13
14
— 15
IE
17
IS
•' 19
™ 20
21
22
23
24
25
26
1 27
26
29
30
31
32
33
34
35
3S
37
36
39
40
41
42
Rep 1"
Rep 2
Rep 31
Moisture1
Dup 1
A1r
Oven
Dup Z
A1r
UA
" VA
H»
Oven
NA
NA
NA
Particle Size
Analysis'1
Cations
NHlOAc
NK4C1
•Moisture is performed in dupl cate; place one sample weight in eacn column. nr»i column
1s air-dry weight, second column Is oven-dry weight.
^Replicates are recorded here; the sample weight recorded by the sample number Is repeated
as Rep 1.
cNot all methods require three replicates.
dflven-dry weight after organic matter removal.
-------
Appendix C
Revision 2
Date: 12/86
Page 36 of 62
AIR DRY SAMPLE WEIGHT IN GRAMS
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM 115b
Lab Name
Bitch ID
Lab Manager's Signature
Sampl e
Nunfcer
01
02
03
04
05
06
07
OB
09
10
11
12
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Rep 1 *
Rep 2
Rep 3**
*Replicat
Exchangeable Cations
In 0.002 M CaCl2
Exchangeable Acidity
Bad 2
es are recorded here; the sample weight recordec
KC1
by the sample
nurtier 1s repeated as Rep 1.
••Not all «ethods require three replicates.
-------
Appendix C
Revision 2
Date: 12/86
Page 37 of 62
Lab Kane
DIRF.CT/DLLAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM U5c
QUALITY CfWROl: AIS DRV SAMPLE WEIGHT IN GRAMS
Batch ID
Lib Manager's Signature
Sampl e
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
4?
Rep 1*
Rep 2
Rep 3**
ExtrtctsDls ft ina Al
Pyrophospftate j Ox*l»te
,
i
|
Cltrate-
Dlthionite
j
!
|
!
'
1
... ,.,, j
i ' '
I
"T " •"" "
j
i
1
| i
1 "'" "1
!
j
H20 Extractable
to|" and NOj
PO?* Extractable
SOi"
•Replicates are recorded h?re; the staple welnht recorded by the saaple nuaber Is repeated
as Rep 1 .
••Not all Methods require tnree replicates.
-------
Appendix C
Revision 2
Date: 12/86
Page 38 of 62
AIR DRY SAMPLE HEIGHT IN GRAMS
DIRECT/DELAYED RESPONSE PROJECT (ODRP) SOIL SURVEY
FORM
Lab Name
Batch ID
Lab Nanager's Signature
Sample
Nintier
)1
)2
13
)4
)5
16
)7
)8
)9
10
11
12
13
14
15
16
[7
18
19
20
21
22" '
23
24
25
26
27
26
59
30' '-
31
32
33 '
34
35
36 '
37
38' "
39" "
40
41
42
Rep I4
Rep 2
Rep 3"
Sulfate Adsorption Isotherm
Initial Solution Concentration
0
2
4
8
•q S/L
16
32
*RepH ales are re orded here the sample neight recoraeo By tne sanpie
number U repeated as Rep 1.
••Mot all •sthods require three replicates.
-------
Appendix C
Revision 2
Date: 12/86
Page 39 of 62
Lab Name
DIRECT/DELAYED RESPONSE PROJICT (DDkP) SU1L SURVEY
FORM 11 be
QUALITY CONTROL: AIR DR,T SAMPLE WtltiHT
bitch ID
Lab Manager's Signature
Sample
Number
01
02
03
04
05
OS
07
06
04
10
H
12
13
14
15
It
17
ie
15
20
21
22
23
24
25
26
27
2B
25
30
31
35
33
34
35
34
37
38
39
4G
41
4J
Rep J&
fcep 2
fcep 3C
Total S.
mg
Total N,
mg
Specific
Surface,"
9
Total C.
mg
Inorganic C.
me
<2 mni
2-20 mm
1
1
p.li. - orv weioht.
TnUr UIJ wctyl'fc.
^Replicates are recorded here; the sample weight recorded by the sample number
1s repeated as Rep 1.
CNOI all methods require three replicates.
-------
Appendix C
Revision 2
Date: 12/86
Page 40 of 62
EXCHANGEABLE BASIC CATIONS In NH40»c
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT (DORP! SOIL SURVEY
FORM U6«
Ub Nine
Bitch ID
lab Hanager's
Sample
Number
Bl
'02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
Z2
23
24
Z5
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Exchangeable Basic CUIoni 1n N^OAc
Solution
Recovered
1n
Syringe (ui
Aliquot Valuw (nD*
Ca
Mj
K
Na
Total Dl'utlon Voljote (»L)*
U
H9
<
Na
i "i
1 _
1
'.
..™_
""._n~~".~
i j i i
i
(_
t~ -•
..._...
L k
- .
L... 1
~T " "T •" ^
L" "t__
" T
Solution Conce' tratlon (rq/L)
Ca
"9
K
Na
BUnk
D-Bl«nk
D-BUnk
D-BUnk
D-Blink"
D-Blank
D-Blank
Total Volune
(n Sa^ile (nil
•Enter U If no dilution Is MC
Aliquot Voluw
1n Dilution (nLI
Total Volume
of Dilution (•!.)
UTTuTf on-Blank
Concentrations (ag/L)
U
"9
K
Ml
t.
-------
Appendix C
Revision 2
Date: 12/86
Page 41 of 62
EXCHANGEABLE BASIC CATIONS IN NH«C1
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELATED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 116b
Lib Name
Mtch ID
Lib Manager's Signature
Simple
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
26
29
30
31
32
33
34
35
36
37
38
35
10
41
42
Exchangeable Basic Citlons 1n NKjCl
Solution
Recovered
1n
Syringe (X.
AHauot Volume (nLl*
C*
Mg
K
Nl
Totll Dilution Volume (mLl*
Ci
"9
K
Nl
Solution Concentntlon (mg/L)
Cl
"9
K
Nl
Blink
D-Blink
"D-Blink
D-Blank"
D-Blank
D-Blank
•B-Blank"
'Enter u1 \
Total Volume
1n Sample (fl)
Aliquot Volume
1n Dilution («L)
Total Volume
of Dilution (mi)
Dilution Blank
Concentrations (»g/L)
Ct
«9
K
Nl
f no dilution It made.
-------
Appendix C
Revision 2
Date: 12/86
Page 42 of 62
CATION EXCHANGE CAPACITY
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES; TITER AND NORMALITY
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 116c
Lab Name
Batch ID
Lab Manager's Signature
TUrant used: NHjOAc HHlC1
Sample
Number
TJ5
~07
~D5
"IB
4
"15
""30
~32
3i
~yt
~i5
~3E
~IB
"35
TO
TT
~TJ
Total
Volume In
Sample (ml)
Cation Exchange Capacity (FIA)
Volume (mL)*
NHjOAc
NH4C1
Total Dilution
VolUM (XL)*
NH40AC
NH4C1
solution
Cone. BO N/L)
NH40AC
HH4C1
Cation Exchange
Capacity (TUratlon)
NH4OAc
THer
(Volume
1n BL)
Nornallty
of
TUrant
NH4C1
"Tite'r
(Volume
In up
Normality
of
Tltrant
Blank
D-B1 ank
D-B1 ank
D-Blank
Cation Exchange Capacity (FIA)
Total
Volume 1n
Sample (mL)
Aliquot
Volume
(mL)
Dilution
Volume
(«U
Dilution
Cone. (•*? N/L)
NHtOAc
Kh^Cl
-------
Appendix C
Revision 2
Date: 12/86
Page 43 of 62
KC1-EXCHANGEABLE ACIDITY AND EXTRACTABLE ALUMINUM
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES; TITER AND NORMALITY
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM 116CC
Lab Name
Batch ID
Lab Manager's Signature
Sampl e
Number
01
02
03
04
05
06
07
OB
09
10
11
12
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Solution
Recovered
In Syringe
<*•>
KCI-Extractable Al
Aliquot
Volume
(at)*
Total Dilution
Voluae
-------
Appendix C
Revision 2
Date: 12/86
Page 44 of 62
EXCHANGEABLE BASIC CATIONS IN CaClj
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM 1160
Lib Nuw
Batch ID
Lab Manager's Signature
Sample
Nunber
01
02
03
04
05
06
07
08
09
10
11
1Z
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
•35 "'•
~3T
37
3B
•35 •-
40
41
42
Total
Volume In
Sanple (*.)•
A11C
C*
uot Volune (nL)D
"9
K
Ma
Exchangeable Baric Cations 1n C»C12
Total Dilution Voluw
-------
Appendix C
Revision 2
Date: 12/86
Page 45 of 62
EXTRACT ABLE Fe AND Al IN CaCl2
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM 116*
Lab Name
Batch 10
Lab Manager's Signature
Sample
Number
01
02
03
04
05
06
07
06
09
10
11
12
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
33
39
40
41
42
Extractable Fe and Al In Cad?
Total
Volume in
Sanple
<*.)•
Aliquot
VoluM (BL)t>
Fe
Al
Total Dilution
Volume («L)b
Fe
Al
Solut
Cane.
Fe
:lon
•q/L)
Al
Soil Type
Mineral (M)
or
Organic (0)
Extraction
Rat1oc
Blank
D-BUnk
D-BUnk
D-Bl«nk
D-Blank
D-Bl«nk
D-BUnk
Extractable Fe and Al In CaClj
Total
Volume In
Sanple (»L>
•Volume added for ex1
Aliquot
Volume
(mL)
Dilution
Volume
(•L)
Dilution
Cone. tag/D
Fe
Al
faction.
btnter u 1f no dilution Is Mde.
cSo11 to solution ratio 1s expressed as l:x; enter
the value of x.
-------
Appendix C
Revision 2
Date: 12/86
Page 46 of 62
DURACTABLE Fe AND Al IN PYRDPHOSPHATE
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT IODRP) SOIL SURVEY
FORM U6M
Lib Nine
Lib Miniger's Slgniture
Bitch ID
Simple
Number
~C9
~~n
~~IZ
1 3
~IS
~T£
^
35
36
37
38
39
40
41
42
Cxtrictibl* Fc ind Al 1n Pyrophosphite
Totil
Volume 1n
Simple (HI*
Aliquot
Volume (*.)">
Fe
Al
Totil Dilution
Voluw (ri.)0
Fe
Al
Solution
Cone. (ag/L)
Fe
Al
Blink
D-Bl»nk
I>-Bl«nk
D-Blank
D-Bl«nk
D-Bl»nk
D-Bl«nk
[xtrictible Fe ind Al In Pyrophotphite
Totil
Volume 1n
Simple (rt.)
Aliquot
Volume
(•L)
Dilution
Volume
(ml)
Dilution
Cone. (»g/L)
Fe
Al
•Volume laded for extrictlon.
bEnter U If no dilution 1s Bide.
-------
Appendix C
Revision 2
Date: 12/86
Page 47 of 62
EXTRACTABLE Fe AND Al IN ACID-OXALATE
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM 116f
Lab Name
Batch 10
Lab Manager's Signature
Saaple
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Blink
D-Bl»nk
D-Blank
D-Bl«nk
D- Blank
D-Blank
D-Blank
Extractable Fe and Al In Acld-Oxalate
Total
Volume
In Sample
(•LI*
Aliquot
Volune (»t)b
Fe
Al
Total Dilution
Volume (ntlO
Fe
Al
Extractable Fe and Al In Acld-Oxalate
Total
Volume In
Sample (it)
Aliquot
Volume
(ml)
Dilution Dilution
Volute Cone. (mg/L)
(*-)
Fe
Al
•Volume added for extraction.
bEnter U If no dilution 1s Bade.
Solution
Cone. (mg/L)
Fe
Al
-------
Appendix C
Revision 2
Date: 12/86
Page 48 of 62
EXTRACTABLE Fe AND Al IN CITRATE-DITHIONITE
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 116ff
Lib Hime
Bitch ID
Lib Miniger's Sljniture
Simple
Hunter
01
02
b3
04
05
5$
07
08
09
10
11
12
13
1*
15
16
17
18
19
20
Zl
22
23
24
25
26
?1
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Extractive Fe ind Al 1n C1trite-D1th1on1te
Total
Volume
1n Simple
(nL)«
Aliquot
Volume (mL)b
Fe
Al
Totil Dilution
Volume (fiL)b
Fe
Al
Blink
D-Blank
D-Blank
D-Blank
0-Blank
D-Bl«nk
D-BUnk
Extrictible Fe and Al 1n C1tnte-D1th1on1te
Totil
Volume 1n
Sample (nL)
Aliquot
Volume
(ml)
D11ut1(
Volume
(mL)
in Dilution
Cone. (mg/L)
Fe
Al
Volume added for extraction.
''Enter U 1f no dilution Is aide.
Solution
Cone. (mg/L)
Fe
Al
-------
Appendix C
Revision 2
Date: 12/86
Page 49 of 62
WATER EXTRACTABLE SULFATE AND NITRATE
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY
FORM 116g
Lab Na
Batch ID
Lab Manager's Signature
Swple
N inter
01
02
03
0*
05
06
07
OH
09
10
11
1Z
13
14
15
16
17
IB
19
20
Zl
ZZ
23
24
Z5
26
Z7
ZB
29
30
31
3Z
33
34
35
36
37
38
39
40
41
42
HjO Extractable Nitrate
Total
Volume
In Simple
(«L)«
Aliquot
Volume
(«.)<>
Total
Dilution
Volute
(•L)°
Solution
Concentration
(•9/L)
H20 Extractable Sulfate
Aliquot
Volume
(•L)b
Total
Dilution
Volune
(rt.)6
Solution
Concentration
(«9/L)
Blank
D-Bl«nk
D-Bl»nk
D-BUnk
Dilution Blank
Total Volume Aliquot Volune Total Volume Concentration!
In Simple lit) In Dilution (it) of Dilution («U ,
NO] SOJ~
Volume added for extraction.
'Enter U If no dilution Is Bade.
-------
Appendix C
Revision 2
Date: 12/86
Page 50 of 62
PHOSPHATE ETTMCTABLE SULFATE
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM 11699
Ltb Nam
"Batch 10
Ltb Manager's Signature
Sample
Ninfier
01
02
03
04
05
06
07
08
09
10
11
1Z
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Blank
D-Bltnk
D-Blank
D-Blank
•Volunr a
bEnter U
P0j~ Extractive Sulfate
Total
Voluw
In Saaple
<*.)*
Total Volime
1n Sample
(•L)
Aliquot
Volume
(«.)"
Total
Dilution
Voluw (nL)b
Solution
Concentration
(a?/L)
Aliquot Voluw Total VoluM Dilution Blank
1n Dilution of Dilution Concentration
(•L) (*.) (iig/Ll
ded for entractlon.
If no dilution It Bade.
-------
Appendix C
Revision 2
Date: 12/86
Page 51 of 62
SULFATE ADSORPTION ISOTHERMS
DILUTION FACTORS AND DILUTION REAGENT BLANK VALUES
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY
FORM 116h
Lab Name
Bitch ID
Lab Manager's Signature
Sample
Number
01
0?
'03
ru "
05
06
07
OB "
09"
"TO
11
12
13
14
~I5
16
IT
IB
19
20
21
'?2
23
24
25
2fi "
27
28
29
'30'11™"
31
32
33 ""
34
35
36"
| 38 " |
1 39
41
'42' "
Sulfatc Adsorption Uothena
Total
Volume
In Sample
(*.)»
Aliquot
Volume (mL)b
0
2
4
8
16
32
Total
Dilution Volume (mL)D
0
2
4
B
16
32
Solution
Concentration (mg/L)
0
2
4
8
|
16
32
•Volume added for adsorption.
bEnter U If no dilution Is made.
-------
Appendix C
Revision 2
Date: 12/86
Page 52 of 62
SUMMARY OF EXCHANGEABLE CATIONS IN NtUOAc
CORRECTED FOR BLANKS AND DILUTIONS
OIRECT/DaAYEO RESPONSE PROJECT (DORP) SOIL SURVEY REPORT FORM 204a
Analytical Lab ID
Batch ID
Prep lab Nane
Date For* Completed
Date Batch Received
Lab Manager's Signature
Remarks
Sample
Nufeer
01
02
03
0«
05
06
07
08
09
10
11
1Z
13
14
5
6
7
8
9
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Exchangeable Cations In NtUOAc.
•eq/lOOg
Ca
"9
K
Na
-------
Appendix C
Revision 2
Date: 12/86
Page 53 of 62
SUMMARY OF EXCHANGEABLE CATIONS IN NH4C1
CORRECTED FOR BLANKS AND DILUTIONS
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 204b
Analytical Lab ID
Batch ID
Prep Lab Nue
Date Fora Completed
Date Batch Received
Lab Manager's Signature
Remarks
Sample
Nunber
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Z6
Z7
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Exchangeable Cations In NHjCI.
•eq/lOOg
Ca
Mg
K
Na
-------
Appendix C
Revision 2
Date: 12/86
Page 54 of 62
SUMMARY OF EXCHANGEABLE CATIONS IN 0.002 M CaCl»
CORRECTED FOR BLANKS AND DILUTIONS
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 204c
Analytical Lab ID
Batch ID
Prep Lab Naw
Date For* Completed
Date Batch Received
Lab Manager's Signature
Retards
Sample
Nunber
01
02
03
04
05
06
07
08
10
11
z
' i
4
15
16
17
18
19
ZO
— n
2Z
"~73
Z«
-25
- v
28
-25 '
30
-31"
-3T" ""
-33"
"3T- "
35
_ 3g.
37
15
"T5~"
-IB
-II" '
42
•Reported
Exchangeable Cations 1n 0.002 M CaClz.
•eq/lOOg
Ca«
Ng
K
Na
Fe
Al
ata nay De negative.
-------
Appendix C
Revision 2
Date: 12/86
Page 55 of 62
SUMMARY OF CATION EXCHANGE CAPACITY (CEC)
CORRECTED FOR BLANKS AND DILUTIONS
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 204d
Analytical Lab ID
Batch ID
Prep Lab Name
Lab Manager's Signature
Remarks
Date Form Completed
Date Batch Received
Sample
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
CEC,
meq/lOOg
NH4OAc
NH4C1
CEC,
meq/lOOg
NH4OAc
22
23
24
2i)
26
2/
28
29
3U
31
32
33
34
35
36
3/
38
39
40
41
42
NH4C1
-------
Appendix C
Revision 2
Date: 12/86
Page 56 of 62
SUMMARY OF EXTRACTABLE IRON AND ALUMINUM DATA
CORRECTED FOR BLANKS AND DILUTIONS
DIRECT/DELAYED RESPONSE PROJECT (ODRP) SOIL SURVEY REPORT FORM 205
Analytical Lab
Batch ID
Prep Lab Name
Remarks
ID
Lab Manager's Signature
Date Form Completed
Date Batch Received
Sample
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
16
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Pyrophosphate
Extra- table.
Height I
Fe
Al
Acld-
Extri
Kelt
Fe
Oxalate
ctable,
ht J
Al
Cltrate-Ditfuonlte
Extr actable,
Height I
Fe
Al
-------
Appendix C
Revision 2
Date: 12/86
Page 57 of 62
SUMMARY OF EXTRACTABLE SULFATE, EXCHANGEABLE ACIDITY. AND
EXTRACTABLE ALUMINUM DATA. CORRECTED FOR BLANKS AND DILUTIONS
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 206
Analytical Lab ID
Batch ID
Prep Lab Name
Remarks
Lab Manager's Signature
Date Form Completed
Date Batch Received
Sample
Number
Extract
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
IS
HW™
20
"71
22
23
24
25
26
27
••28
29
30
31
32
ir~
34
35
-3?
-37..-. ...,
38
39
TC
41
42
Extractable
Nitrate
*g N/kg
HjO
Extractable Sulfate.
•9 S/kg
HjO
POf
Exchangeable Acidity.
•eq/lOOg
Bad 2
KC1
Extractable
A1. wq/lOOg
KC1
-------
Appendix C
Revision 2
Date: 12/86
Page 58 of 62
SUMMARY OF SULFATE-ADSORPTION ISOTHERM DATA
CORRECTED FOR BLANKS* AND DILUTIONS
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 207
Analytical Lab ID
Batch ID
Prep Lab Name
Remarks
Lab Manager's Signature
Date Form Completed
Date Batch Received
Sample
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Sulfate Remaining in solution, mg S/L
Initial solution Concentration, me
0
2
4
8
5/ L
16
32
'Blanks are double-del oniied water.
-------
Appendix C
Revision 2
Date: 12/86
Page 59 of 62
SUMMARY OF TOTAL C, N. S. SPECIFIC SURFACE, AND INORGANIC CARBON DATA
CORRECTED FOR BLANKS AND DILUTIONS
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 208
Analytical Lab ID
Batch ID
Prep Lab Name
Remarks
Lab Manager's Signature
Date Form Completed
Date Batch Received
Sample
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
Z6
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Total
s.
Height X
Total
N.
Height I
Specific
Surface.
m*/g
Total
C,
Height X
Inorg!
He1
<2 mm
_
m1c C,
iht X
2-20 mm
-------
Appendix C
Revision 2
Date: 12/86
Page 60 of 62
Lab ID
Batch ID
Prep Lab Maine
Remarks
PARTICLE SIZE ANALYSIS RAW DATA
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY REPORT FORM 303b
Lab Manager's Signature
___^__________ Date Form Completed .
Date Batch Received '
Cylinder volume (ml)
PI pet Volume (mL)
weight of Fraction, grams
Size Class and Particle Diameter (mm)
Sand
Sample
Number
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
IB
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
Sand
(2.0-
0.05)
Clay and
Fine S1lt
(<0.02)
Clay
(<0.002)
Very
Coarse
(2.0-
1.0)
Coarse
(1.0-
0.5)
Medium
(0.5-
0.25)
Fine
(0.25-
0.1)
Very Fine
(0.1-
0.05)
-------
Appendix C
Revision 2
Date: 12/86
Page 61 of 62
SUMMARY OF B»C12 - EXCHANGEABLE ACIDITY RAH DATA
DIRECT/DELAYED RESPONSE PROJECT -(DORP) SOIL SURVEY REPORT FORM 306
Analytical Lab ID
Batch ID
Prep Lab Name
Remarks
Lab Manager's Signature
Date Form Completed _
Date Batch Received
Sample
Number
Extract
01
OZ
03
04
05
06
07
08
09
10
11
12
13
1*
15
16
17
18
19
20
21
22
"23
24
25
Z6
~~57
28
Z9
—30
31
32
33
3*
~35"
36
"37
• 38
~39
11 40
41
42
Bid 2 - Exchangeable Acidity
T1ter
(Volume
In H)
Normality
of TUrant
-------
Appendix C
Revision 2
Date: 12/86
Page 62 of 62
SUHKARY OF TOTAL C. N. S. SPECIFIC SURFACE. AND INORGANIC CARBON RAW DATA
DIRECT/DELAYED RESPONSE PROJECT (DDRP) REPORT FORM 306
Analytical Lab ID
Batch ID
Prep Lab Name
Remarks
Lab Manager's Signature
Date Font Couple ted
Date Batch Received
Sample
Number
01
02
03
04
05
06
07
OB
09
ID
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
'26 "
27
2B
29
30
31
32
33
34
35
36
37
38
39
40
'41 "
42
Total
s.
K9
Total
M.
W
Specific Surface.
•g EGME
added
retained
Total
C.
MS
Inorganic C.
pg
<2 M
2-20 mm
-------
Appendix D
Revision 2
Date: 12/86
Page 1 of 8
Appendix D
Forms for Reporting Mineralogical Laboratory Data
The following forms are used for recording data from the mineralogical procedures detailed
in sections 17 through 19.
-------
Appendix D
Revision 2
Date: 12/86
Page 2 of 8
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY FORM 400
Data from Randomly Oriented Powder Mounts
Analytical Lab ID:
Analyst:
Batch No.:
Date Received:
Date Completed:
Lab Manager's Signature:
Sample Number:
Size Fraction: <2-mm <0.002-mm
(circle one)
*2e
S SBSC"
ssxxa
d(A)
[ = 3 = 33 = 3 =
I/I,
!3ss.sss:33
Minerals (in order
of highest to
least abundance)
888888X88888888888:
1
2
3
4
5
6
7
8
9
Mineral
Name
'3S333333S3!
EBB8888888S
%
E333:
»•*•«••»••«•*•
JCPDS
Card
Number
5333333S8S
: = = = = = = = = =
• fi*^ wis a i
hkl
• B3S333
:SS333S
• SiSi^SiKSS^SS^S^iES
Integrated
Area
5333333333333:
E33S3333333S3S
Major Peaks
1
•
d(A)
I/I
2
•
d(A)
I/I
3
o
d(A)
I/I
m ~ •• «• S S 5
RIR
ESBSSSS
: = = = = = :
5SS3SS333B33333
Half-Height
Peak Width
:assss8sa888S8B
:BBSsssBssassaa
Confirming
Peak
e
d(A)
I/I
Degree
of
Match
XSS>SSSSa:B888B8S838S38SS8a8S8SSSBSBSSSSSBSSBSSS8SSSS8SSSB
t jtsBSsaa=»=sss=========
-------
Appendix D
Revision 2
Date: 12/86
Page 3 of 8
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY FORM 401
Data from Oriented Pi pet Mounts
Analytical Lab ID:
Analyst:
Batch No.:
Date Received: _
Date Completed:
Lab Manager's Signature:
Treatment: (circle one)
Mg - sat.
K - sat.
A D
A D
GLY
110'C 350'C 550'C
"20
d(A)
sasaaasaasaaaBaasaaasBa
I/I
Mineral
Name
JCPDS
Card
Number
hkl
Response to
Treatment
B3t
Weight from Section 17.10.5
g freeze-dried <0.002-mm material.
-------
Appendix D
Revision 2
Date: 12/86
Page 4 of 8
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY FORM 402a
Chemical Composition of Minerals by Wavelength-dispersive XRF
Analytical Lab ID:
Analyst:
Batch No.:
Date Received:
Date Analyzed:
Lab Manager's Signature:
Sample No.:
Elements
Major Oxide
Sodium Na?0
Potassium KpO
Rubidium Rb?0
Magnesium MgO
Calcium CaO
Strontium SrO
Aluminum Al?03
Silicon Si 62
Phosphorus P20$
Iron* ^6203
Manganese Mn02
Titanium Ti02
TOTAL
Concen'
Elemental ,
wt%
NA
tration
Oxide,
wtZ
2o
error
NA
I/Kb)
NA
Detection
Limit
NA
*The iron value represents both the +2 and +3 states of iron,
Comments:
-------
Appendix D
Revision 2
Date: 12/86
Page 5 of 8
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY FORM 402b
Chemical Composition of Minerals by Wavelength-Dispersive XRF
Analytical Lab ID:
Analyst:
Batch No.:
Date Received:
Date Analyzed:
Lab Manager's Signature:
Sample No.:
Minor and Trace
Elements
Sul fur S
Chloride Cl
Barium Ba
Lead Pb
Nickel Ni
Copper Cu
Cobalt Co
Chromi urn Cr
Zfnc Zn
Uranium U
Thorium Th
Zirconium Zr
Niobium Nb
Cerium Ce
Concentr
Elemental ,
(wtZ or ppm)
•ation
Oxide,
(wt% or ppm)
2a
error
I/Kb)
Detection
Limit
-------
Appendix D
Revision 2
Date: 12/86
Page 6 of 8
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY FORM 403
Pertinent Geometry and Instrument Settings Specific to the System
Analytical Lab ID:
SEM Machine Name: EDXRF Machine Name:_
Operator: Date Completed:
Lab Manager's Signature:
1. X-ray detector to specimen fixed angle and azimuth
2. X-ray detector to specimen distance
3. X-ray detector active area
4. X-ray detector window
5. Specimen tilt angle and tilt azimuth
6. Specimen to SEM pole piece working distance (adjusted on the electron beam
axis to the main constant for every spectral collection).
7. SEM operating voltage:
8. SEM beam current (±10%):_
9. SEM spot size:
10. SEM scan rate (preferred as fast as possible):_
11. Specimen area fluoresced: ; volume excited:_
12. Magnification: ; full frame or partial field:_
13. Spectral acquisition time (dead-time corrected):
14. Spectrometer pulse shaping time constant:_
electron volts/channel: "
15. Average absorbed current:_
16. Average input count rate:_
-------
Appendix D
Revision 2
Date: 12/86
Page 7 of 8
DIRECT/DELAYED RESPONSE PROJECT (DDRP) SOIL SURVEY FORM 404
Comments on Observations, Photographs, and Areas of Analysis
Analytical Lab ID: Batch No:
Analyst: Date Received:
Date Completed:
Lab Manager's Signature:
-------
Appendix D
Revision 2
Date: 12/86
Page 8 of 8
DIRECT/DELAYED RESPONSE PROJECT (DORP) SOIL SURVEY FORM 405
SEM Photograph and Chemical Composition of Minerals
Analytical Lab ID: Batch No:
Analyst: Date Received:
Date Completed:
Lab Manager's Signature:
Clay Mineral: yes no(circle one)
Light Mineral: yes no (circle one)
Heavy Mineral: yes no (circle one) If yes, include:
Wt % Heavy Minerals Wt % Light Minerals
Sample Number: Mineral Name:
(Attach Photograph Here)
Magnification:
Composition: (Attach spectrum to the back of this sheet)
-------
Appendix E
Revision 2
Date: 12/86
Page 1 of 2
Appendix E
Glossary
Air-dried soil
Aluminum potential (KJ
Base saturation percentage
Batch
Capacity-protected systems
DDI water
Delayed response systems
Direct response systems
Endogenous level
Instrumental detection limit
- Soil that has reached equilibrium with the air; the moisture
content does not change by more than 5 percent in a 40-
g sample over a 24-hour period.
- 3 pH - pAI.
- Extent to which the adsorption complex of a soil saturated
with exchangeable cations other than hydrogen; expressed
as a percentage of the total cation exchange capacity.
- A group of as many as 42 samples including 1 preparation
duplicate, at least 2 audit samples, and as many as 39
routine samples and field duplicates.
- Watersheds in which surface waters will not become
acidic for centuries to millennia.
- Water which meets ASTM Type II reagent grade specifica-
tions; prepared by double distillation, double deionization,
or a combination of distillation and deionization; having a
conductivity of less than 1.0 ^mho/cm at 298° K (28°C).
- Watersheds in which surface waters will become acidic in
the time frame of a few mean water residence times to
several decades (10 to 100 years).
- Watersheds with surface waters that either are presently
acidic (alkalinity <0) or will become acidic within a few (3
to 4) mean water residence times.
- Naturally occurring concentration of analyte within the
sample.
- Three times the standard deviation of ten nonconsecutive
replicate calibration blank analyses run on separate days.
If a signal is not obtained for a blank analysis, then the
instrumental detection limit is defined as 3 times the
standard deviation of 10 nonconsecutive replicate analyses
of a standard whose concentration is 4 times the lesser
of the actual detection limit or the required detection limit.
K-factor
Lime potential
- The number of pV/fjg for acetanilide standard for carbon
and nitrogen determinations.
- pH - 1/2 pCa.
-------
Appendix E
Revision 2
Date: 12/86
Page 2 of 2
Mean water residence time
Mineral soil
Organic soil
Oven-dried (OD) soil
Sesquioxides
Set
Soil
Maximum amount of time for complete replacement of all
the water within the permeable strata of the watershed.
Soil that contains greater than 80 percent mineral matter.
Soil that contains greater than 20 percent organic matter.
Soil that has been dried for 24 hours at the prescribed
temperature in a convection oven: 105 °C for mineral soils,
60 °C for organic soils.
Generally considered to be iron (Fe2OJ and aluminum
(Al-Pa) oxides. More specifically, sesquioxides are combi-
nations of these two minerals in a one-to-two ratio.
A group of samples that were sampled by an individual
crew on one day.
Unconsolidated mineral and organic material on the
immediate surface of the earth that serves as a natural
medium for the growth of land plants.
U.S. GOVERNMENT PRINTING OFFICE 1990/748-159/00449
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