xvEPA
United States
Environmental Protection
Agency
Environmental Monitoring
Systems Laboratory
P.O. Box 15027
Las Vegas NV 89114-5027
EPA/600/8-87/005
January. 1987
Pre-lssuance Copy
Research and Development
National Surface
Water Survey
Stream Survey (Pilot,
Middle-Atlantic Phase I,
Southeast Screening,
and Middle-Atlantic
Episode Pilot)
Analytical Methods Manual
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NATIONAL SURFACE WATER SURVEY
STREAM SURVEY (PILOT, MIDDLE-ATLANTIC PHASE I,
SOUTHEAST SCREENING, AND MIDDLE-ATLANTIC EPISODE PILOT)
ANALYTICAL METHODS MANUAL
by
D. C. Hillman, S. H. Pia,
and S. J. Simon
Lockheed-Engineering and Management Services Company, Inc.
Las Vegas, Nevada 89114
Contract No. 68-03-3249
Project Officer
R. D. Schonbrod
Exposure Assessment Research Division
Environmental Monitoring Systems Laboratory
Las Vegas, Nevada 89114
ENVIRONMENTAL MONITORING SYSTEMS LABORATORY
OFFICE OF RESEARCH AND DEVELOPMENT
U. S. ENVIRONMENTAL PROTECTION AGENCY
LAS VEGAS, NEVADA 89114
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NOTICE
This document is a preliminary draft. It has not been formally released
by the U.S. Environmental Protection Agency and should not at this stage be
construed to represent Agency policy. It is being circulated for comments on
its technical merit and policy implications.
The mention of trade names or commercial products in this manual is for
illustration purposes, and does not constitute endorsement or recommendation
for use.
ii
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ABSTRACT
The National Surface Water Survey of the National Acid Precipitation
Assessment Program is a three-phase project to evaluate the current water
chemistry of lakes and streams, determine the status of fisheries and other
biotic resources, and select regionally representative surface waters for a
long-term monitoring program to study changes in aquatic resources.
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 compar-
able. For these reasons, the same reliable, detailed analytical methodology
must be available to and used by all analysts participating in the study.
This manual provides details of the analytical methods and internal qual-
ity control used to process and analyze samples for the National Stream Survey
(NSS). The determinations and methods described are the following:
Parameter
1. Base-Neutralizing Capacity
2. Acid-Neutralizing Capacity
3. Aluminum, total
4. Aluminum, total extractable
5. Aluminum, Nonexchangeable
Pyrocatechol Violet (PCV)
Reactive and Total PCV Reactive
6. Ammonium, dissolved
7. Calcium, dissolved
8. Chloride, dissolved
9. Fluoride, total dissolved
10. Inorganic carbon, dissolved
11. Iron, dissolved
12. Magnesium, dissolved
13. Manganese, dissolved
14. Nitrate, dissolved
15. Organic carbon, dissolved
16. pH
17. Phosphorus, total dissolved
18. Potassium, dissolved
Method
Titration with Gran analysis
Titration with Gran analysis
202.2 AAS (furnace)
Extraction with 8-hydroxyquinoline
into MIBK followed by AAS (furnace)
Automated Colorimetric Pyrocatechol
Violet (PCV)
Automated colorimetry (phenate)
AAS (flame) or ICPES
Ion chromatography
Ion-selective electrode and meter
Instrument (acidification, C02
generation, IR detection)
AAS (flame) or ICPES
AAS (flame) or ICPES
AAS (flame) or ICPES
Ion chromatography
Instrument (uv-promoted oxidation,
CO? generation, IR detection)
pH electrode and meter
Automated colorimetry
(Molybdate blue)
AAS (flame)
iii
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Parameter Method
19. Silica, dissolved Automated colorimetry
(molybdate blue)
20. Sodium, dissolved AAS (flame)
21. Sulfate, dissolved Ion chromatography
22. Specific conductance Conductivity cell and meter
23. True color Comparison to platinum-cobalt
color standards
24. Turbidity Instrument (nephelometer)
iv
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ACKNOWLEDGMENT
Contributions provided by the following individuals were essential to
the completion of this methods manual and are gratefully acknowledged: Mark
Peden (Illinois State Water Survey), Kevin Cabbie, Lynn Creel man, Sevda
Drouse, D. Mericus, Janice Engels (Lockheed Engineering and Management Services
Company, Inc.), James Kramer (McMaster University), John Lawrence (National
Water Research Institute), Bruce LaZerte (Ontario Ministry of the Environment),
John Nims (State of Maine, Department of Environmental Protection), Charles
Driscoll and Gary Schafron (Syracuse University), J. Messer (U.S. EPA), Howard
May (U.S. Geological Survey), Peter Campbell (University of Quebec), Richard
Wright (University of Virginia), David Brakke (Western Washington University),
and R. Kent Schreiber (U.S. Dept. of the Interior).
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Section T of C
Revision 2
Date: 11/86
Page 1 of 9
TABLE OF CONTENTS
Section Page Revision
1.0 INTRODUCTION 1 of 6 2
1.1 Background of the National Stream Survey. 1 of 6 2
1.2 Physical Parameters and Analytes Measured 3 of 6 2
1.2.1 Base-Neutralizing Capacity (BNC) . . 3 of 6 2
1.2.2 Acid-Neutralizing Capacity (ANC) . . 3 of 6 2
1.2.3 Aluminum, Total Extractable 3 of 6 2
1.2.4 Aluminum, Total 5 of 6 2
1.2.5 Aluminum, Nonexchangeable Pyrocatechol
Violet (PCV) and Total PCV Reactive 5 of 6 2
1.2.6 Dissolved Inorganic Carbon 5 of 6 2
1.2.7 Dissolved Ions (Na, K, Ca, Mg, Fe,
Mn, NH4, F, Cl, $04, N03 5 of 6 2
1.2.8 Dissolved Organic Carbon 5 of 6 2
1.2.9 Dissolved Silica (Si02) 5 of 6 2
1.2.10 pH 5 of 6 2
1.2.11 Specific Conductance 6 of 6 2
1.2.12 Total Dissolved Phosphorus 6 of 6 2
1.2.13 True Color 6 of 6 2
1.2.14 Turbidity 6 of 6 2
1.3 References 6 of 6 2
2.0 FIELD OPERATIONS 1 of 45 2
2.1 Personnel 1 of 45 2
2.2 Daily Operations 1 of 45 2
2.2.1 Activities Before Sample Arrival . . 1 of 45 2
2.2.2 Activities Following Sample Arrival. 1 of 45 2
2.3 Determination of DIC 12 of 45 2
2.3.1 Scope and Application 12 of 45 2
2.3.2 Summary of Method 15 of 45 2
2.3.3 Interferences 15 of 45 2
2.3.4 Safety 15 of 45 2
2.3.5 Apparatus and Equipment 15 of 45 2
2.3.6 Reagents and Consumable Materials. . 15 of 45 2
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Section T of C
Revision 2
Date: 11/86
Page 2 of 9
TABLE OF CONTENTS (Continued)
Section Page Revision
2.3.7 Sample Collection, Preservation,
and Storage 16 of 45 2
2.3.8 Calibration and Standardization. .. 16 of 45 2
2.3.9 Quality Control 16 of 45 2
2.3.10 Procedure 18 of 45 2
2.3.11 Calculations 19 of 45 2
2.3.12 Reporting 19 of 45 2
2.4 Determination of pH 19 of 45 2
2.4.1 Scope and Application 19 of 45 2
2.4.2 Summary of Method 19 of 45 2
2.4.3 Interferences 19 of 45 2
2.4.4 Safety . 19 of 45 2
2.4.5 Apparatus and Equipment 19 of 45 2
2.4.6 Reagents and Consumable Materials. . 22 of 45 2
2.4.7 Sample Collection, Preservation,
and Storage 22 of 45 2
2.4.8 Calibration and Standardization. .. 22 of 45 2
2.4.9 Quality Control 23 of 45 2
2.4.10 Procedure 23 of 45 2
2.4.11 Calculations 25 of 45 2
2.4.12 Reporting 25 of 45 2
2.5 Determination of Turbidity 25 of 45 2
2.5.1 Scope and Application 25 of 45 2
2.5.2 Summary of Method 25 of 45 2
2.5.3 Interferences 25 of 45 2
2.5.4 Safety 25 of 45 2
2.5.5 Apparatus and Equipment 25 of 45 2
2.5.6 Reagents and Consumable Materials. . 26 of 45 2
2.5.7 Sample Collection, Preservation,
and Storage 26 of 45 2
2.5.8 Calibration and Standardization. .. 26 of 45 2
2.5.9 Quality Control 26 of 45 2
2.5.10 Procedure 26 of 45 2
2.5.11 Calculations 27 of 45 2
2.5.12 Reporting 27 of 45 2
2.6 Determination of True Color 27 of 45 2
2.6.1 Scope and Application 27 of 45 2
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Section T of C
Revision 2
Date: 11/86
Page 3 of 9
TABLE OF CONTENTS (Continued)
Section Page Revision
2.6.2 Summary of Method 29 of 45 2
2.6.3 Interferences 29 of 45 2
2.6.4 Safety 29 of 45 2
2.6.5 Apparatus and Equipment 29 of 45 2
2.6.6 Reagents and Consumable Materials. . 29 of 45 2
2.6.7 Sample Collection, Preservation,
and Storage 29 of 45 2
2.6.8 Calibration and Standardization. .. 29 of 45 2
2.6.9 Quality Control 29 of 45 2
2.6.10 Procedure 29 of 45 2
2.6.11 Calculations 30 of 45 2
2.6.12 Reporting 30 of 45 2
2.7 Determination of Nonexchangeable Pyrocatechol
Violet (PCV) Reactive and Total PCV
Reactive Aluminum 30 of 45 2
2.7.1 Scope and Application 30 of 45 2
2.7.2 Summary of Method 30 of 45 2
2.7.3 Definitions 31 of 45 2
2.7.4 Interferences 31 of 45 2
2.7.5 Safety 31 of 45 2
2.7.6 Apparatus and Equipment 31 of 45 2
2.7.7 Reagents and Consumable Materials. . 32 of 45 2
2.7.8 Sample Collection, Preservation, and
Storage 34 of 45 2
2.7.9 Calibration and Standardization. .. 34 of 45 2
2.7.10 Quality Control 35 of 45 2
2.7.11 Procedure 35 of 45 2
2.7.12 Calculations 38 of 45 2
2.7.13 Precision and Accuracy 38 of 45 2
2.8 Aliquot Preparation 38 of 45 2
2.8.1 Summary 38 of 45 2
2.8.2 Safety 40 of 45 2
2.8.3 Apparatus and Equipment 40 of 45 2
2.8.4 Reagents and Consumable Materials. . 40 of 45 2
2.8.5 Procedure 41 of 45 2
2.9 References 44 of 45 2
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Section T of C
Revision 2
Date: 11/86
Page 4 of 9
TABLE OF CONTENTS (Continued)
Section Page Revision
3.0 ANALYTICAL LABORATORY OPERATIONS 1 of 17 2
3.1 Summary of Operations 1 of 17 2
3.2 Sample Receipt and Handling 1 of 17 2
3.3 Sample Analysis 1 of 17 2
3.4 Internal Quality Control Requirements ... 1 of 17 2
3.4.1 Method Quality Control . 5 of 17 2
3.4.2 Overall Internal Quality Control . . 10 of 17 2
3.5 Data Reporting 14 of 17 2
3.6 References 14 of 17 2
4.0 DETERMINATION OF BASE-NEUTRALIZING CAPACITY,
ACID-NEUTRALIZING CAPACITY, AND pH 1 of 27 2
4.1 Scope and Application 1 of 27 2
4.2 Summary of Method 1 of 27 2
4.3 Interferences 1 of 27 2
4.4 Safety 1 of 27 2
4.5 Apparatus and Equipment 2 of 27 2
4.6 Reagents and Consumable Materials 2 of 27 2
4.7 Sample Collection, Preservation, and
Storage 3 of 27 2
4.8 Calibration and Standardization 3 of 27 2
4.9 Quality Control 14 of 27 2
4.10 Procedure 17 of 27 2
4.11 Calculations 20 of 27 2
4.12 References 26 of 27 2
5.0 DETERMINATION OF AMMONIUM 1 of 7 2
5.1 Scope and Application 1 of 7 2
5.2 Summary of Method 1 of 7 2
5.3 Interferences 1 of 7 2
5.4 Safety 1 of 7 2
5.5 Apparatus and Equipment 1 of 7 2
5.6 Reagents and Consumable Materials 2 of 7 2
5.7 Sample Collection, Preservation, and
Storage 3 of 7 2
5.8 Calibration and Standardization 3 of 7 2
5.9 Quality Control 3 of 7 2
5.10 Procedure 4 of 7 2
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Section T of C
Revision 2
Date: 11/86
Page 5 of 9
TABLE OF CONTENTS (Continued)
Section Page Revision
5.11 Calculations 4 of 7 2
5.12 Precision and Accuracy 4 of 7 2
5.13 References 5 of 7 2
6.0 DETERMINATION OF CHLORIDE, NITRATE, AND SULFATE
BY ION CHROMATOGRAPHY 1 of 6 2
6.1 Scope and Application 1 of 6 2
6.2 Summary of Method 1 of 6 2
6.3 Interferences 2 of 6 2
6.4 Safety 2 of 6 2
6.5 Apparatus and Equipment 2 of 6 2
6.6 Reagents and Consumable Materials 3 of 6 2
6.7 Sample Collection, Preservation, and
Storage 4 of 6 2
6.8 Calibration and Standardization 4 of 6 2
6.9 Quality Control 4 of 6 2
6.10 Procedure 5 of 6 2
6.11 Calculations 6 of 6 2
6.12 Precision and Accuracy 6 of 6 2
6.13 References 6 of 6 2
7.0 DETERMINATION OF DISSOLVED ORGANIC CARBON AND
DISSOLVED INORGANIC CARBON 1 of 8 2
7.1 Scope and Application 1 of 8 2
7.2 Summary of Method 1 of 8 2
7.3 Interferences 1 of 8 2
7.4 Safety 1 of 8 2
7.5 Apparatus and Equipment 1 of 8 2
7.6 Reagents and Consumable Materials 2 of 8 2
7.7 Sample Collection, Preservation, and
Storage 4 of 8 2
7.8 Calibration and Standardization 4 of 8 2
7.9 Quality Control 6 of 8 2
7.10 Procedure 6 of 8 2
7.11 Calculations 7 of 8 2
7.12 Precision and Accuracy 7 of 8 2
7.13 References 7 of 8 2
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Section T of C
Revision 2
Date: 11/86
Page 6 of 9
TABLE OF CONTENTS (Continued)
Section Page Revision
8.0 DETERMINATION OF TOTAL DISSOLVED FLUORIDE BY
ION-SELECTIVE ELECTRODE 1 of 6 2
8.1 Scope and Application 1 of 6 2
8.2 Summary of Method 1 of 6 2
8.3 Interferences 1 of 6 2
8.4 Safety. 1 of 6 2
8.5 Apparatus and Equipment 2 of 6 2
8.6 Reagents and Consumable Materials 2 of 6 2
8.7 Sample Collection, Preservation, and
Storage 3 of 6 2
8.8 Calibration and Standardization 3 of 6 2
8.9 Quality Control 4 of 6 2
8.10 Procedure 4 of 6 2
8.11 Calculations 5 of 6 2
8.12 Precision and Accuracy 5 of 6 2
8.13 References 5 of 6 2
9.0 DETERMINATION OF TOTAL DISSOLVED PHOSPHORUS. . . 1 of 8 2
9.1 Scope and Application 1 of 8 2
9.2 Summary of Method 1 of 8 2
9.3 Interferences 1 of 8 2
9.4 Safety 2 of 8 2
9.5 Apparatus and Equipment 2 of 8 2
9.6 Reagents and Consumable Materials 2 of 8 2
9.7 Sample Collection, Preservation, and
Storage 4 of 8 2
9.8 Calibration and Standardization 4 of 8 2
9.9 Quality Control 4 of 8 2
9.10 Procedure 5 of 8 2
9.11 Calculations 5 of 8 2
9.12 Precision and Accuracy 5 of 8 2
9.13 References 7 of 8 2
10.0 DETERMINATION OF DISSOLVED SILICA 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 and Equipment 1 of 7 2
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Section T of C
Revision 2
Date: 11/86
Page 7 of 9
TABLE OF CONTENTS (Continued)
Section Page Revision
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 5 of 7 2
10.10 Procedure 5 of 7 2
10.11 Calculations 5 of 7 2
10.12 References 5 of 7 2
11.0 DETERMINATION OF SPECIFIC CONDUCTANCE 1 of 4 2
11.1 Scope and Application 1 of 4 2
11.2 Summary of Method 1 of 4 2
11.3 Interferences 1 of 4 2
11.4 Safety. 1 of 4 2
11.5 Apparatus and Equipment 1 of 4 2
11.6 Reagents and Consumable Materials 2 of 4 2
11.7 Sample Collection, Preservation, and
Storage 2 of 4 2
11.8 Calibration and Standardization 2 of 4 2
11.9 Quality Control 3 of 4 2
11.10 Procedure 3 of 4 2
11.11 Calculations 3 of 4 2
11.12 Precision and Accuracy 4 of 4 2
11.13 References 4 of 4 2
12.0 DETERMINATION OF METALS (Al, Ca, Fe, K, Mg, Mn,
Na) BY ATOMIC ABSORPTION SPECTROSCOPY 1 of 23 2
12.1 Scope and Application 1 of 23 2
12.2 Summary of Method 1 of 23 2
12.3 Definitions 3 of 23 2
12.4 Interferences 3 of 23 2
12.5 Safety 5 of 23 2
12.6 Apparatus and Equipment 5 of 23 2
12.7 Reagents and Consumable Materials 6 of 23 2
12.8 Sample Collection, Preservation, and
Storage 7 of 23 2
12.9 Calibration and Standardization 7 of 23 2
12.10 Quality Control 8 of 23 2
12.11 Procedure 8 of 23 2
12.12 Calculations 22 of 23 2
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Section T of
Revision 2
Date: 11/86
Page 8 of 9
TABLE OF CONTENTS (Continued)
Section Page Revision
12.13 References 23 of 23 2
13.0 DETERMINATION OF DISSOLVED METALS (Ca, Fe, Mg, Mn)
BY INDUCTIVELY COUPLED PLASMA EMISSION
SPECTROSCOPY 1 of 10 2
13.1 Scope and Application 1 of 10 2
13.2 Summary of Method 1 of 10 2
13.3 Interferences 2 of 10 2
13.4 Safety 6 of 10 2
13.5 Apparatus and Equipment 6 of 10 2
13.6 Reagents and Consumable Materials 6 of 10 2
13.7 Sample Handling, Preservation, and Storage. 7 of 10 2
13.8 Calibration and Standardization 8 of 10 2
13.9 Quality Control 8 of 10 2
13.10 Procedure 8 of 10 2
13.11 Calculations 8 of 10 2
13.12 Precision and Accuracy 10 of 10 2
13.13 References 10 of 10 2
APPENDICES
A CLEANING OF PLASTICWARE 1 of 2 2
A-1.0 Sample Containers 1 of 2 2
A-l.l Cleaning of Plasticware 1 of 2 2
B BLANK DATA FORMS 1 of 16 2
C EXAMPLES OF CALCULATIONS REQUIRED FOR ANC
AND BNC DETERMINATIONS 1 of 24 2
C-1.0 HC1 Standardization (Section 4.8.1). ... 1 of 24 2
C-2.0 NaOH Standardization (Section 4.8.2) ... 4 of 24 2
C-2.1 Initial NaOH Standardization with KHP
(Section 4.8.2.1) 4 of 24 2
C-2.2 Standardization Check (Section 4.8.2.2). . 6 of 24 2
C-2.3 Routine NaOH Standardization with
Standardized HC1 (Section 4.8.2.3) . . . 8 of 24 2
C-3.0 Electrode Calibration (Section 4.8.3). .. 11 of 24 2
C-4.0 Blank Analysis - ANC Determination
(Section 4.9.2) 14 of 24 2
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Section T of C
Revision 2
Date: 11/86
Page 9 of 9
TABLE OF CONTENTS (Continued)
Section Page Revision
C-5.0 Sample Analysis 16 of 24 2
C-5.1 Titration Data 16 of 24 2
C-5.2 Initial Estimate of YI, (Section 4.11.1). 17 of 24 2
C-5.3 Initial Estimate of V2, ANC, BNC, and C
(Section 4.11.3.1) 17 of 24 2
C-5.4 Refined Estimates of Y! and Y£ 19 of 24 2
C-5.5 New Estimates of ANC, BNC, and C 21 of 24 2
C-5.6 Comparison of Latest Two Estimates of
Total Carbonate 21 of 24 2
C-6.0 Quality Control Calculations 23 of 24 2
C-6.1 Comparison of Calculated ANC and Measured
ANC (Section 4.9.6) 23 of 24 2
C-6.2 Comparison of Calculated and Measured
BNC (Section 4.9.7) 23 of 24 2
C-6.3 Comparison of Calculated Total Carbonate
and Measured Total Carbonate
(Section 4.9.8) 24 of 24 2
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Section Figures
Revision 2
Date: 11/86
Page 1 of 1
FIGURES
Figure Page Revision
1.1 Organizational diagram of the National Surface Water
Survey and the years during which field activities
are to be initiated 2 of 6 2
2.1 Flow scheme of daily mobile processing laboratory
activities 6 of 45 2
2.2 Field sample label 8 of 45 2
2.3 Aliquot and Audit Sample Labels 9 of 45 2
2.4 NSWS Form 5 - Batch/QC Field Data 10 of 45 2
2.5 NSWS Form 3 - Shipping 13 of 45 2
2.6 Data flow scheme 14 of 45 2
2.7 Flow scheme for DIG determination 17 of 45 2
2.8 Schematic of pH measurement system 20 of 45 2
2.9 pH sample chamber 21 of 45 2
2.10 Flow scheme for pH determinations 24 of 45 2
2.11 Flow scheme for turbidity determinations 28 of 45 2
2.12 Channel one schematic for total PCV reactive Al ... 36 of 45 2
2.13 Channel two schematic for nonexchangeable PCV
reactive Al 37 of 45 2
5.1 Ammonia manifold AA I 6 of 7 2
5.2 Ammonia manifold AA II 7 of 7 2
9.1 Total dissolved phosphorus manifold 6 of 8 2
10.1 Silica manifold 7 of 7 2
12.1 Standard Addition Plot 9 of 23 2
C-l Plot of Fib versus V for HC1 standardization 3 of 24 2
C-2 Plot of F3b versus V for initial NaOH standardization
with KHP 5 of 24 2
C-3 Plot of FI versus V for standardization check-
titration of NaOH with HC1 7 of 24 2
C-4 Plot of FI versus V for routine NaOH standardization. 10 of 24 2
C-5 Plot of pH versus pH* for electrode calibration ... 13 of 24 2
C-6 Plot of FI versus V for ANC determination of
blank 15 of 24 2
C-7 Plot of Fia versus Va for initial determination of Vi 18 of 24 2
C-8 Plot of FIC versus Va for Vi determination. ..... 20 of 24 2
C-9 Plot of F£C versus V^ for ^2 determination 22 of 24 2
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Section Tables
Revision 2
Date: 11/86
Page 1 of 1
TABLES
Table Page Revision
1.1 Required Minimum Analytical Detection Limits, Expected
Ranges, and Intralab Relative Precision 4 of 6 2
2.1 Mobile Processing Laboratory Equipment List 2 of 45 2
2.2 List of Sample Codes 11 of 45 2
2.3 Aliquot Descriptions 39 of 45 2
3.1 List of Aliquots, Containers, Preservatives, and
Corresponding Parameters to be Measured 2 of 17 2
3.2 List of Holding Times 3 of 17 2
3.3 List of Parameters and Corresponding Measurement Methods . 4 of 17 2
3.4 Summary of Internal Method Quality Control Checks 6 of 17 2
3.5 Maximum Control Limits for Quality Control Samples .... 7 of 17 2
3.6 Factors to Convert mg/L to ueq/L 11 of 17 2
3.7 Chemical Reanalysis Criteria 12 of 17 2
3.8 Conductance Factors of Ions 13 of 17 2
3.9 List of Data Forms 15 of 17 2
3.10 National Surface Water Survey Data Qualifiers 16 of 17 2
4.1 List of Calculation Procedures for Combinations of
Initial YI and pH* 21 of 27 2
4.2 List of Frequently Used Equations and Constants 22 of 27 2
6.1 Suggested Concentration of Dilute Calibration Standards. 4 of 6 2
6.2 Typical 1C Operating Conditions 5 of 6 2
6.3 Single-Operator Accuracy and Precision 6 of 6 2
9.1 Percent Recovery of Total P in the Presence of SiOg. ... 1 of 8 2
9.2 Precision and Accuracy of the Method for Natural Water
Samples 7 of 8 2
9.3 Precision and Accuracy of the Method for Analyst-
Prepared Standards 7 of 8 2
12.1 Atomic Absorption Concentration Ranges 2 of 23 2
13.1 Recommended Wavelengths and Estimated Instrumental
Detection Limits 2 of 10 2
13.2 Analyte Concentration Equivalents (mg/L) Arising from
Interferents at the 100 mg/L level 4 of 10 2
13.3 Interferent and Analyte Elemental Concentrations Used
for Interference Measurements in Table 13.2 5 of 10 2
13.4 Inductively Coupled Plasma Precision and Accuracy Data . . 9 of 10 2
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Section 1.0
Revision 2
Date: 11/86
Page 1 of 6
1.0 INTRODUCTION
The National Surface Water Survey (NSWS) is part of the National Acid
Precipitation Assessment Program (NAPAP). One of the responsibilities of
NAPAP is to assess the extent and severity to which aquatic resources
within the U.S. are at risk because of effects of acid deposition.
The NSWS was initiated at the request of the Administrator of EPA when it
became apparent that existing data could not be used to quantitatively
assess the present chemical and biological status of surface waters of the
U.S. Extrapolation of existing data, largely compiled through individual
studies, to the regional or national scale was limited because studies
were often biased in terms of site selection. Additionally, many previous
studies were incomplete with respect to the chemical variables of
interest, inconsistent relative to sampling/analytical methodologies, or
highly variable in terms of data quality.
1.1 Background of the National Stream Survey
The NSWS is divided into two major components (Figure 1.1), the National
Lake Survey (NLS) and the National Stream Survey (NSS), each of which has
three phases. This document pertains to Phase I of the NSS (NSS-I) and a
Phase I pilot survey that was conducted as a trial prior to the full NSS-I
sampling effort.
The NSS-I involves a synoptic chemical survey of streams in the Eastern
U.S. and was designed to alleviate uncertainty in making regional
assessments based on existing data by:
(1) providing data from a subset of streams which are characteristic
of the overall population of streams within a region;
(2) using standardized methods in collection of chemical data;
(3) measuring a complete set of variables thought to influence or
be influenced by surface-water acidification;
(4) providing data which can be used to statistically investigate
relationships among chemical variables on a regional basis; and
(5) providing reliable estimates of the chemical status of streams
within a region of interest.
The U.S. Environmental Protection Agency (EPA) requires that data collec-
tion 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. The goals of the EPA in designing the NSS-I were to clearly
identify NSS-I objectives; identify intended uses and users of the data;
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Section 1.0
Revision 2
Date: 11/86
Page 2 of 6
NATIONAL SURFACE WATER SURVEY (NSWS)
NATIONAL LAKE SURVEY (NLS)
NATIONAL STREAM SURVEY (NSS)
PHASE I
Synoptic Chemistry
Eastern Survey (1984)
PHASE I
Synoptic Chemistry
Western Survey (1985)
PHASE I
Pilot Survey
(1985)
Phase II
Temporal
Variability
(1986)
Phase II
Biological
Resources
(1986)
Phase I Synoptic Survey
(1986)
Phase III Long-Term Monitoring
(1987)
Phase II
Temporal
Variability
(1987)
Phase II
Biological
Resources
(1987)
Phase III Long-Term Monitoring
(1987)
Figure 1.1. Organizational diagram of the National Surface Water Survey
and the years during which field activities are to be initiated.
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Section 1.0
Revision 2
Date: 11/86
Page 3 of 6
develop an overall conceptual and practical approach to meeting the objec-
tives; develop an appropriate survey design; identify the quality of data
needed; develop analytical protocols and quality assurance/quality control
(QA/QC) procedures; test the approach through a "pilot" or feasibility
study; and revise and modify the approach and methodology as needed.
By using these criteria as guidelines, NSS-I was designed to provide statis-
tically comparable data which could be extrapolated with a known degree of
confidence to a regional or national scale. The conceptual approach to
the survey emphasized that the data would not be used to ascribe observed
effects to acidic deposition phenomena. Rather, the intent of the survey
was to provide information for the development of correlative, not cause-
and-effect, relationships through large-scale monitoring activities.
The Quality Assurance Plan (Drouse et al., 1986) provides details of the
extensive external and internal QA and QC activities for the Phase-I
Pilot and NSS-I.
This manual provides details of the analytical methods and internal QC
used to process and analyze the stream samples. Details of the actual
sampling and on-site stream analyses are provided in the field operations
manual (Hagley et al., 1986).
1.2 Physical Parameters and Analytes Measured
The constituents and parameters to be measured, along with a rationale for
each, are listed below. Table 1.1 lists the required detection limits,
relative precision goals, and expected ranges.
1.2.1 Base-Neutralizing Capacity (BNC)
BNC is the BNC of a sample due to dissolved C02, hydro-
nium, and hydroxide. In conjunction with ANC, this measurement
is useful in refining calculations for both ANC and BNC. (An
iterative calculation procedure is performed. During each
iteration, improved values for ANC and BNC are generated).
1.2.2 Acid-Neutralizing Capacity (ANC)
ANC is a measure of all bases in a sample and is an indication
of buffering capacity. Negative ANC is an indication of mineral
BNC (mineral BNC = - ANC).
1.2.3 Aluminum, Total Extractable
Total extractable aluminum is an estimate of dissolved aluminum
and includes most mononuclear aluminum species. Aluminum is
considered to be highly toxic especially to fish. Knowing its
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TABLE 1.1. REQUIRED MINIMUM ANALYTICAL DETECTION LIMITS, EXPECTED RANGES,
AND INTRALAB RELATIVE PRECISION
Parameter3
Units
Required
Detection Expected
Limit Range
Relative
Intralab
Precision Goal
BNC
ANC
Al, Total
Extractable
peq/L
ueq/L
mg/L
5 10-150 10
5 -100-1000 10
0.005 0.005-1.0 10(A1>0.01),20(A1<0.01)
Al Total mg/L
Al, Nonexchangeable mg/L
and Total PCV Reactive
Ca mg/L
0.005 0.005-1.0 10(A1>0.01),20(A1<0.01)
Cl
DIC
DOC
F, Total dissolved
Fe
K
Mg
Mn
Na
NH4
N03
P, Total dissolved
pH, Field
pH, Lab
Si02
S04
Specific Conductance
True Color
Turbidity
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
mg/L
pH units
pH units
mg/L
mg/L
uS/cm
PCU units6
NTU
0.010
0.01
0.01
0.05
0.1
0.005
0.01
0.01
0.01
0.01
0.01
0.01
0.005
0.002
0.05
0.05
d
0
0.010-0.800 10(A1>0.01),20(A1<0.01)
0.5-
0.2-
0.1-
0.1-
0.01-
0.01-
0.1-
0.1-
0.01-
0.5-
0.01-
0.01-
0.005-
3-
3-
i-20
10
20
50
0.2
5
1
7
5
7
2
5
5
10
5(DOO5),10(DOC<5)
5
10
5
5
10
5
5
10
0.07 10(P>0.01),20(P<0.01)
-8 ±0.1C
-8 ±0.05C
2-25
1-
5-
0-
20 5
1000 1
200 ±5C
2-15
10
Dissolved ions and metals are being determined except where noted.
bUnless otherwise noted, this is the relative precision at concentrations
above 10 times instrumental detection limits.
cAbsolute precision goal is in terms of applicable units.
dBlank must be <0.9 uS/cm.
ePCU = platinum-cobalt units.
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concentration is important in assessing the biological environ-
ment of a stream.
1.2.4 Aluminum, Total
Total aluminum is an estimate of the potential aluminum pool
available to the biological environment.
1.2.5 Aluminum, Nonexchangeable Pyrocatechol Violet (PCV) and Total
PCV Reactive
Exchangeable PCV reactive aluminum, measured as the difference
between total reactive and nonexchangeable reactive, is that
fraction of soluble aluminum species biologically available and
considered toxic to fish. It is therefore important to know the
relative amount of the exchangeable species to assess the
biological environment of a stream.
1.2.6 Dissolved Inorganic Carbon
The field determination of dissolved inorganic carbon (DIC) is
necessary in determining the degree of dissolved C02 saturation
in a stream. Both the field and lab determinations of DIC (com-
bined with pH) are useful in QA/QC calculations.
1.2.7 Dissolved Ions (Na, K, Ca, Mg, Fe, Mn, NH4, F, Cl, S04, N03)
These are determined in order to chemically characterize the
stream especially for mass ion balance and buffering capacity.
Fluoride is also important as an aluminum chelator.
1.2.8 Dissolved Organic Carbon
Dissolved organic carbon (DOC) determination is necessary to
establish a relationship with color and to estimate the
concentration of organic acids. Also, DOC is important as
a natural chelator of aluminum.
1.2.9 Dissolved Silica (Si02)
The absence or existence of dissolved silica is an important
factor controlling diatom blooms, and it assists in identifying
trophic status. It is also an indication of mineral weathering.
1.2.10 pH
pH is a general and direct indication of free hydrogen ion
concentration.
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1.2.11 Specific Conductance
The conductance of stream water is a general indication of its
ionic strength and is related to buffering capacity.
1.2.12 Total Dissolved Phosphorus
This is an indicator of potentially available nutrients for
phytoplankton productivity and overall trophic status.
1.2.13 True Color
True color, measured in PCU (platinum-cobalt units), is an indi-
cator of organic acids and DOC. Substances which impart color
may also be important natural chelators of aluminum.
1.2.14 Turbidity
Turbidity is a measure of suspended material in a water column
and is measured in nephelometric turbidity units (NTU).
1.3 References
Drouse, S. K., D. C. Hillman, L. W. Creelman, and S. J. Simon, 1986.
National Surface Water Survey - Stream Survey (Pilot, Middle-Atlantic
Phase I, Southeast Screening, and Middle-Atlantic Episode Pilot)
Quality Assurance Plan.
Hagley, C. A., C. M. Knapp, C. L. Mayer, and F. A. Morris, 1986. The
National Surface Water Survey Stream Survey (Pilot, Middle-Atlantic
Phase I, Southeast Screening, and Middle-Atlantic Episode Pilot)
Field Training and Operations Manual.
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2.0 FIELD OPERATIONS t
Field operations are based at fully equipped mobile processing labora-
tories (MPL) in Las Vegas (for the pilot study the MPL were in the field)
A list of equipment contained in the MPL is given in Table 2.1. Stream
samples, collected by sampling crews, are sent by Federal Express to the
MPL for preliminary analysis, processing, and shipment to analytical
laboratories for more detailed analysis.
The activities of the MPL crew are described in this section. Sampling
crew activities are described elsewhere (Hagley et al., 1986).
2.1 Personnel
The MPL is staffed by a crew consisting of a coordinator, supervisor,
chemist, and analysts. Coordinators are responsible for the overall
operation of the MPL including coordination with the sampling crews,
sample tracking and logistics, data forms, and safety. The supervisor
with the assistance of the chemist and analysts is responsible for MPL
measurements and sample processing.
2.2 Daily Operations
The MPL operates each day that samples arrive. The daily MPL activities
are outlined in Figure 2.1 and are divided into activities that are
conducted before sample arrival (Section 2.2.1) and activities that are
conducted following sample arrival (Section 2.2.2).
2.2.1 Activities Before Sample Arrival
Prior to sample arrival, the reagents for determining DIG, pH, and PCV
Al, and for preparing aliquot 2 (total extractable Al) are prepared as
described in sections 2.3, 2.4, 2.7, and 2.8, respectively. Also, the
carbon analyzer, pH meter, nephelometer, and the flow injection analyzer
(FIA) are calibrated as described in sections 2.3, 2.4, 2.5, and 2.7,
respectively.
2.2.2 Activities Following Sample Arrival
After samples are delivered by the carrier, the steps outlined in
Figure 2.1 are performed. The first step, performed by the coordinator,
involves organizing the samples into a batch. The next six steps
(aliquot preparation and pH, DIG, color, PCV Al and turbidity determina-
tions) are performed simultaneously by the supervisor and analysts.
Finally, after all measurements and processing are finished, the data
forms are completed, the samples are packed, and the forms and samples
are shipped to their destinations. These steps are detailed in sections
2.2.2.1 through 2.2.2.4.
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TABLE 2.1. MOBILE PRQCESSING LABORATORY EQUIPMENT LIST
Mobile Lab Equipped with
a. Electrical and water inputs
b. Water outlet
c. Source of water meeting ASTM Type I specifications (such as Barnstead
NANOpure/ROpure 40 or Millipore Milli-RO/Super-Q System)
d. Heating/cooling system
e. Freezer
f. Laminar-flow hood delivering class 100 air
g. Solvent storage cabinet
h. Standard laboratory countertops and sink
i. Analytical balance and plastic weighing boats
2. Centrifuge (capable of holding four 50-mL tubes)
3. Clean 4-L Cubitainers
4. Clean Nalgene Amber Wide-Mouth Bottles
a. 500-mL (Nalgene No. 2106-0016)
b. 250-mL (Nalgene No. 2106-0008)
c. 125-mL (Nalgene No. 2106-0004)
5. Total Extractable Aluminum Supplies
a. Clean 50-mL graduated centrifuge tubes
with sealing caps (Fisher No. 05-538-55A)
b. 10-mL polypropylene test tubes (Elkay No.
000-2024-001
c. Plug Tite sealing caps (Elkay No. 127-0019-200)
d. HPLC-grade methyl isobutyl ketone (MIBK)
e. Sodium acetate (Alfa ultrapure)
f. 8-hydroxyquinoline (99+ percent purity)
g. NfyOH (30 percent - Baker Instra-Analyzed grade)
h. Clean 1-L, 500-mL, and 100-mL volumetric flasks
i. Glacial acetic acid (Baker Instra-Analyzed grade)
j. Hydrochloric acid (12 M - Baker Instra-Analyzed grade)
k. Phenol-red indicator solution (0.04 percent w/v -
American Scientific Products 5720)
1. 2.00-mL Repipet dispenser
m. 3.00-mL Repipet dispenser top for 1-gallon bottle
n. 5.00-mL Repipet dispenser
o. 100-mL reagent bottle with dropper (Nalgene 2411-0060)
p. Polystyrene graduated cylinders
(25-, 100-, 250-mL sizes)
- 1
- 30/day
- 30/day
- 60/day
- 90/day
- 30/day
- 30/day
- 30/day
- 180 mL/day
- 80 g/month
- 30 g/month
- 750 mL/month
- 5 of each
- 100 mL/month
- 500 mL/month
- 1 L
- 21 station
- 21 station
- 2/station
- 2/station
- 2 each/station
(continued)
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TABLE 2.1. (Continued)
Section 2.0
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Page 3 of 45
6. Color Determination Kit (Hach Model CO-1)
7. Color Kit Spare Supplies
a. Color disc (Hach No. 2092-00)
b. Color viewing tube (Hach No. 1730-00)
c. Hollow polyethylene stoppers (Hach No. 14480-74)
8. Filtration Apparatus and Supplies
a. Membrane filters, 0.45 urn, 47-mm diameter
(Gelman No. 60173) (package of 100)
b. Teflon or plastic forceps
c. Fisher filtrator - low form (Fisher 09-788)
d. Acrylic vacuum chambers (custom made)
e. Clean filter holder (Nalgene No. 310-4000)
f. Spare rubber stoppers (Fisher No. 09-788-2)
g. Vacuum pump with regulator (Mi Hi pore No. xx5500000)
9. Disposable Gloves (talc-free)
10. Preservation Supplies
a. Repipet Jr. (0.1 ml)
b. Indicating pH paper (Whatman Type CS No. 2626-990
range 1.8 - 3.8)
c. HN03 and H2$04 (Baker Ultrex grade or Seastar
Ultrapure grade)
11. Frozen Freeze Gel Packs - daily use (reuseable)
- shipping
12. Styrofoam-Lined Shipping Containers
13. Field Data Forms, Shipping Forms, Batch Forms, etc.
14. Color Blindness Test Kit
15. DIC Determination Supplies
a. Dohrman DC-80 carbon analyzer
b. 50-mL polypropylene syringes - station use
- field use
c. Mininert syringe valves - station use
- field use
- 2
2
10
10
- 7 pkg/week
- 5
- 3
- 6
- 12
- 6
- 1
- 2 pkg/week
- 2
- 6 packs/week
- 50 ml/week
- 25/day
- 30/40 sample
batch
- 4/day
- 1
1
50
I/sample
20
70
(continued)
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Page 4 of 45
TABLE 2.1. (Continued)
d. Zero-grade nitrogen gas
e. Anhydrous NagCC^ (ACS Primary Standard Grade)
f. Syringe membrane filters (Gelman Acrodisc
4218, 0.45 urn)
g. Spare carbon analyzer parts (nuts, ferrules,
tubing, etc.)
16. MPL pH Supplies
a. pH meter (Orion Model 611)
b. Orion Ross epoxy body combination pH electrode
c. Filling solution for Ross combination pH
electrode (pack of 6 bottles)
d. pH sample chamber
e. Certified 0.100 N H2S04
f. Ringstand (to hold pH apparatus) and clamps
g. NBS-traceable pH buffers (pH 4 and 7)
h. 50-mL disposable beakers
Turbidimeter (Monitek Model 21)
Turbidimeter Supplies
a. 5-, 10-, 20-, 50-, 100-, 200-NTU standards
b. Cuvettes
Class 100 Air Filtration Filters
Spare Water Treatment Cartridges
Coolers
Clean 20-L Cubitainers with Spigots
Digital Micropipets (5-40 uL, 40-200 uL, 200-1,000 uL,
1,000-5,000 uL)
Micropipet Metal-Free Pi pet Tips (in four sizes
corresponding to micropipet sizes in item 23)
17.
18,
19.
20.
21.
22.
23.
24.
25. Reagents for PCV Aluminum Procedure
a. Hydrochloric acid (Ultrex grade or equivalent)
b. 1,10-Phenanthroline
- 1 cylinder/
month
- 500 g
- I/sample
2
6
2
2
2 L
2
2 L of each/
month
200
- 1
1 L of each
10
6
6
4
5
1 of each
2 cases (1,000
tips/case)
of each size
(continued)
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Section 2.0
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Page 5 of 45
TABLE 2.1. (Continued)
c. Hydroxylammonium chloride
d. Pyrocatechol violet
e. Hexamethylenetetraamine
f. Ammonium hydroxide
g. Aluminum standard
h. Ion-exchange resin
i. Nucleopore polycarbonate filters
j. Syringe filter holder
k. Nitric acid (Ultrex grade or equivalent)
1. Polystyrene divinyl benzene beads
26. Flow injection analyzer (Lachat)
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Section 2.0
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Before Sample Arrival
1. Prepare reagents for
a) Total extractable Al
b) DIG
c) pH
d) PCV Al
2. Warm up and calibrate instruments
a) Turbidimeter
b) Carbon analyzer
c) pH meter
d) FIA
Samples
Following Sample Arrival
1. Insert required audit samples, assign
batch and ID numbers, start batch form
2. Determine DIG
3. Prepare aliquots
4. Measure pH
5. Measure turbidity
6. Determine true color
7. Determine aluminum species
8. Complete batch and shipping forms
9. Ship samples
10. Distribute data
Figure 2.1. Flow scheme of daily mobile processing laboratory activities.
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Section 2.0
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Page 7 of 45
2.2.2.1 Sample Identification and Batch OrganizationThree types of samples
(routine, duplicate, and blank) are collected and delivered to the
MPL. The sample type is indicated on the sample label (Figure 2.2).
The samples collected on a given day are organized into a batch
consisting of the routine, duplicate, and blank samples collected on
that day as well as audit samples (inserted daily at the MPL).
After organization, a unique batch ID number is assigned to each
batch and is recorded on the labels (and corresponding aliquot
labels) of all samples in the batch. Next, an ID number is randomly
assigned to each sample as follows:
Routine Samples - Five sample containers are filled at each stream,
namely, four syringes (for DIG, pH, PCV Al determination) and a cubi-
tainer. One ID number is assigned to all five containers and is
recorded on each container label.
Duplicate and Blank Samples - ID numbers are assigned in the same
manner as for the routine samples. (Note: There are no syringe
samples for the blank.)
Field Audit Samples - One 2-1 field audit sample (received each day
from a central source) is inserted into each day's batch of samples.
The field audit sample is assigned an ID number in the same manner
as a routine sample, and the number is recorded on the label (Figure
2.3a).
Lab Audit Samples - One lab audit sample (received from a central
source) is included in each day's batch. A single lab audit sample
consists of a set of seven aliquots. Each aliquot has a temporary
label (Figure 2.3b) listing the aliquot number, audit sample code,
preservative amount, and shipping date. The lab audit sample is then
assigned batch and sample ID numbers in the same manner as for a
routine sample. An aliquot label (Figure 2.3c) is attached to each
aliquot, and the batch and sample ID numbers are recorded on the
label as are the date and amount of preservative added.
After the batch and sample ID numbers have been assigned and recorded
on each sample label, the same information is recorded on Form 5,
Batch/QC Field Data (Figure 2.4). Codes necessary to complete the
form are given in Table 2.2.
NOTE 1: The ID numbers are randomly assigned to all samples in a
batch. Furthermore, ID numbers run consecutively from 1 to
the number of samples in the batch. Audit samples must not
always be assigned the same ID number.
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Section 2.0
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Page 8 of 45
STREAM ID
U/L
CREW
DATE SAMPLED
TIME SAMPLED
PROGRAM
|~| PHASE I
|~| SCREENING
I"""! EPISODE PILOT
SAMPLE TYPE
| ROUTINE
| DUPLICATE
I BLANK
EPISODE TYPE
BASE - EPISODE ONLY
BASE - EPISODE AND PHASE I
RISING
PEAK
FALLING
BATCH ID
SAMPLE ID
Revised l-8b
Figure 2.2. Field sample label.
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Section 2.0
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Page 9 of 45
FIELD AUDIT SAMPLE
Radian ID No.
Date
Shipped
Code
Batch
Date
Received
ID
a. Field Audit Sample
Label
LAB AUDIT SAMPLE
Aliquot No.
Date Shipped
Date Received
Code
Preservative Amount
b. Lab Audit Sample Label
Al 1 quot
Batch ID
Sample ID
Date Sampled
Preservative
Amount
Parameters
c. Aliquot Label
Note: The aliquot
no., preservative,
and parameters are
preprinted on the
seven aliquot
labels.
Figure 2.3. Aliquot and Audit Sample Labels.
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Section 2.0
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Page 10 of 45
NATIONAL SURFACE WATER SURVEY
BATCH/QC FIELD DATA FORM
DATE RECEIVED
BY DATA MOT
O FORM 2 LAKES
OR
O FORM 5 STREAMS
CUT* ouAumus «,» ««i AHI AVMUUU ron use ON THIS F
OUALOTtH
Figure 2.4. NSWS Form 5 - Batch/QC Field Data.
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Section 2.0
Revision 2
Date: 11/86
Page 11 of 45
TABLE 2.2. LIST OF SAMPLE CODES
Sample Type
Code
Description
Normal3
Audit
Episodic
R
D
B
TD
F L 1-001
EB
ER
EP
EF
Ml
M2
S
Routine Stream Sample
Duplicate Stream Sample
Field Blank Sample
Trailer Duplicate
Radian I.D. Number
Concentrate lot number
Concentration Level
L = low, N = Natural
Type of Audit Sample (F = FIELD, L = LAB)
Episodic sample, base hydrograph
Episodic sample, rising hydrograph
Episodic sample, peak hydrograph
Episodic sample, falling hydrograph
Initial Middle Atlantic Phase I Sample
Final Middle Atlantic Phase I Sample
Southeast Screening Sample
aNormal samples require a Stream ID.
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Section 2.0
Revision 2
Date: 11/86
Page 12 of 45
NOTE 2: Field audit samples are processed exactly like routine stream
samples. Lab audit samples receive no field treatment other
than labeling and shipping.
NOTE 3: Seven (eight for the Pilot Study) different aliquots are
prepared from each field sample (routine, duplicate, or
blank). Each aliquot is assigned the same batch and ID
number as the sample from which it is prepared.
NOTE 4: After Form 5 is completed, the temporary label on the lab
audit sample (seven aliquots) is removed and placed in the
lab audit logbook.
2.2.2.2 Determination of DIG, pH, Turbidity, True Color, and PCV AlThese
parameters are measured as described in sections 2.3, 2.4, 2.5, 2.6,
and 2.7, respectively.
2.2.2.3 Aliquot PreparationSeven aliquots (eight for the Stream Study
Pilot) are prepared from each sample, each with the same batch and
sample ID numbers. The details for preparing each aliquot are
provided in section 2.8.
2.2.2.4 Form Completion, Sample Shipment, and Data DistributionAfter a
batch has been completely processed, the supervisor records all
analytical data on Form 5 (Figure 2.4). The coordinator then reviews
and signs the form. Next, each aliquot is sealed in a plastic bag
and is packed in a Styrofoam-1ined shipping container along with
7 to 10 frozen freeze-gel packs (to maintain aliquots at 4°C). A
shipping form (Figure 2.5) is then completed and enclosed with each
container, and the containers are shipped by overnight delivery to
its destination. Finally, copies of Forms 1 (a form completed by the
sampling crew for each sample), 3, and 5 are sent to the locations
indicated in Figure 2.6.
2.3 Determination of PIC
2.3.1 Scope and Application
This method is applicable to the determination of DIC in natural surface
waters and is written specifically for the NSWS. DIC is determined in
NSWS mobile processing laboratories by using a Dohrman DC-80 Carbon
Analyzer. For this reason, the method has been written with the assump-
tion that the DC-80 is being used (Xertex - Dohrman Corp., 1984). The
method detection limit (MDL) for DIC determined from replicate analyses
of a calibration blank (approximately 0.1 mg/L DIC) is 0.1 mg/L DIC. A
1.00-mL sample volume was used to determine the MDL. The applicable
analyte concentration range is 0.1 to 50 mg/L DIC.
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Section 2.0
Revision 2
Date: 11/86
Page 13 of 45
ATONAL KMFACt WATER &KVEV
tAAPlE MANAOEMENT OFFICE
tJO. K» I
ALEXANDRIA.VA 11314
news
FORM 9
SHIPPING
RECEIVED PT __________
IF ^COMPLETE WMEWATeLY NOTlFTt
tAA»>LE MAMAGEMENT OFFICE
(703) SST-1490
FROM
CSTATON O)|
AMPVC
«
01
0<
09
04
OS
0«
07
oa
ot
10
1 1
It
13
14
19
It
IT
It
It
to
tl
tz
(3
*4
C9
St
IT
SB
t*
90
TO
(LAB)i
tATCM
10
OATt tAMPLEO
H.QUOTS SHWCD
CFOI 9TATON USE OM.V)
1
t
>
4
9
t
T
DATE IMFPEO DATE RECEIVED
Mt-tUNO. _______
AMU CONOITOi k^OM LAt MSCCVT
(FONL«tUSEOM.T>
OUAUFCXSi
VI AUOUOT tMWEO
Mi AUOuOTHBSMCDUETOOESTIIOYEOtMPLE
WHITE - FCLOOCFT
TCiiow-tMOOtrr
tO.0 - LA* OOFT FOX MCTtlM tO MO
Figure 2.5. NSWS Form 3 - Shipping.
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Section 2.0
Revision 2
Date: 11/86
Page 14 of 45
ANALYTICAL
LABORATORY
Form 3 (2 copies)
MOBILE
PROCESSING
LABORATORY
(keeps 1 copy
of Forms 1,
3, and 5)
Form 3 (1 copy).
SAMPLE
MANAGEMENT
OFFICE
Form 3
QA
MANAGER
(EMSL-Las Vegas)
Forms 1 and 5
DATA
BASE
(Oak Ridge)
Forms 1 and 5
Figure 2.6. Data flow scheme.
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Section 2.0
Revision 2
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Page 15 of 45
2.3.2 Summary of Method
Samples for DIG determination are collected and sealed at the stream
sites in syringes. At the MPL, a syringe filter is attached to the
syringe, and sample is filtered into the sample loop of the DC-80. The
sample is subsequently injected into a reaction chamber containing 5
percent phosphoric acid. The carbonates (DIG) in the sample react with
the acid to form C02 which is sparged from the reaction chamber with a
nitrogen gas carrier stream. The C02 in the carrier stream is then
detected and quantified (in terms of DIG) by an infrared (IR) C02
analyzer.
2.3.3 Interferences
No interferences are known.
2.3.4 Safety
The calibration standards, sample types, and most reagents used in
this method pose no hazard to the analyst. Protective clothing (lab
coat and gloves) and safety glasses must be used when handling
concentrated phosphoric acid.
The nitrogen cylinder must be secured in an upright position. The
line pressure must be kept below 40 psi.
2.3.5 Apparatus and Equipment
2.3.5.1 Dohrman DC-80 Carbon Analyzer equipped with High Sensitivity Sampler
(1.00-mL loop).
2.3.5.2 Reagent bottles for DIG standards (equipped with three-valve cap to
permit storage under a COg-free atmosphere, Rainin No. 45-3200).
2.3.5.3 0.45-um syringe filters (Cellulose nitrate).
2.3.5.4 60-mL plastic syringes.
2.3.5.5 Luer-Lok syringe valves.
2.3.6 Reagents and Consumable Materials
2.3.6.1 Nitrogen Gas (99.9 percent)C02-free.
2.3.6.2 Phosphoric Acid (5 percent v/v)Carefully add 50 ml concentrated
phosphoric acid (H^PO^ sp gr 1.71) to 500 ml water. Mix well
and dilute to 1,000 ml with water.
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Section 2.0
Revision 2
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Page 16 of 45
2.3.6.3 Stock DIG Quality Control Sample SolutionWeekly, open a fresh
ampule of anhydrous, primary standard grade sodium carbonate
and dissolve 8.825 g in water, then dilute to 1.000 L. Store at
4°C in a special reagent bottle under a C02~free atmosphere.
2.3.6.4 Stock DIG Calibration Standard SolutionBiweekly, open a fresh
ampule of anhydrous, primary standard grade N32C03 and dissolve
8.825 g in water, then dilute to 1.000 L. Store at 4°C in a
special reagent bottle under a C02~free atmosphere.
2.3.6.5 WaterWater used in all preparations must conform to ASTM specifica-
tions for Type I water (ASTM, 1984). Such water is obtained from the
Millipore Milli-Q water system.
2.3.7 Sample Collection, Preservation, and Storage
Samples are collected and sealed in 60-mL plastic syringes. They are
stored at 4°C until use.
2.3.8 Calibration and Standardization
2.3.8.1 Set up and operate the DC-80 according to the manufacturer's instruc-
tions.
2.3.8.2 Calibration Standard (10.00 mg/L DIC)Prepare the calibration
standard daily by diluting 5.000 ml of the stock DIC calibration
standard to 500.00 ml with fresh water. Store in a special reagent
bottle under a C02~free atmosphere.
2.3.8.3 Erase previous calibration. Load the sample loop with the 10.00-mg/L
DIC calibration standard by flushing with 7 to 10 ml solution.
Inject and start the analysis. When the analysis is complete, repeat
the process twice more.
2.3.8.4 Calibrate the analyzer by pushing the calibrate button. This com-
pletes the calibration. Sample results are output directly in mg/L
DIC.
2.3.9 Quality Control
QC procedures are outlined in Figure 2.7 and are described in sections
2.3.9.1 through 2.3.9.5.
2.3.9.1 Initial Calibration Verification and Linearity CheckImmediately
after calibration, analyze two QC samples to ensure the calibration
validity and linearity.
-------
Prepare calibration and QC standards.
I Perform Initial calibration!
(three 10-ng/L analyses). I
Hake Initial callb. linearity check
1. Analyze 2 mg/L QC sample
2. Analyze 20 g/L QC sample
YES/ Are Measured values
2.0 i 0.2 and 20.0 +_ O.S ng/L?
Record value 1n logbook,
and record value for 2.00
ng/L QC sample on Fom 5.
YES
Analyze calibration
blank. Is value <0.l
9/L7
Record value In logbook.
_L
Analyze up to 10 samples.'
NO X^Analyze 2.00 ag/L QC sample.^
measured value 2.0 + 0.21
Section 2.0
Revision 2
Date: 11/86
Page 17 of 45
Check Instrunent operation
and standard preparation.
Record sample result
and unacceptable QC
result on Form 5.
YES
Record QC result
and previous sanple
results on Fora 5.
Analyze one sanple per batch In duplicate.
^Reanalyze sample associated with unacceptable QC result.
Does enough volume
renaln of previous
samples for re anal-
ysis?
Figure 2.7. Flow scheme for DIC determination.
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Daily, prepare a 2.00-mg/L and a 20.00-mg/L DIG QC sample by diluting
1.000 and 10.00 ml of the stock DIG QC sample, respectively, to
500.00 mL with fresh water. Store each DIG QC sample in a special
. reagent bottle under a C02~free atmosphere.
Analyze the QC samples. The results must be 2.0 ± 0.2 and 20.0 ± 0.5
mg/L DIG. If the results do not fall within these ranges, a problem
exists in the calibration, standard preparation, or QC sample prepa-
ration. The problem must be resolved prior to sample analysis, and
the QC samples must be reanalyzed. Acceptable results must be
obtained before continuing.
2.3.9.2 Continuing Calibration VerificationTo check for calibration drift,
analyze the 2.00-mg/L DIC QC sample after every 10 samples and after
the last sample. The measured value must be 2.0 ± 0.2 mg/L DIC. If
it is not, repeat the calibration and reanalyze all samples analyzed
since the last acceptably analyzed QC sample.
2.3.9.3 Calibration Blank AnalysisAfter the initial calibration, analyze a
fresh calibration blank. It must contain less than 0.1 mg/L DIC. If
it does not, check the water system and repeat the calibration pro-
cedure (including preparation of standards).
2.3.9.4 Duplicate AnalysisTo determine the analytical precision, analyze
one sample per batch in duplicate.
2.3.9.5 Detection Limit DeterminationDetermine the detection limit by
analyzing 20 blank samples. The detection limit is defined as three
times the standard deviation.
2.3.10 Procedure
2.3.10.1 Check that the DC-80 is equilibrated and that a stable baseline has been
achieved.
2.3.10.2 Prepare calibration standard and calibrate the analyzer.
2.3.10.3 Perform the necessary QC analyses. Proceed with sample analysis if
acceptable results are obtained.
2.3.10.4 Place a syringe valve on the sample syringe and filter 7 to 10 mL of
sample directly into the sample loop. Inject the sample and start
the analysis. Discard the syringe filter after a single use.
2.3.10.5 Thirty seconds after injection, switch the valve to the load position
and load the next sample. The analysis time for a single sample is
3 to 4 minutes.
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2.3.10.6 At the end of the day, rinse the sample loop with water. Keep the
power to the IR analyzer on at all times.
2.3.11 Calculations
No calculations are necessary. Sample results are output on the printer
directly in mg/L DIG.
2.3.12 Reporting
Record the batch and sample ID numbers directly on the printer output.
Similarly identify QC samples. Attach the printout to the logbook.
Record the sample and QC data on Form 2.
2.4 Determination of pH
2.4.1 Scope and Application
This method is applicable to the determination of pH in surface waters
of low ionic strength and is written specifically for the NSWS. For the
NSWS, pH is determined in the MPL using an Orion Model 611 pH meter and
an Orion Ross combination pH electrode. As a result, the method has
been written assuming that the Orion meter and electrode are used (Orion,
1983). The applicable pH range is 3 to 11.
2.4.2 Summary of Method
Samples for pH determination are collected and sealed in syringes at the
stream site. At the field station, pH is measured in a closed system to
prevent atmospheric exposure. The measurement is performed by attaching
the sample syringe to the pH sample chamber (Figures 2.8 and 2.9), by
injecting sample, and by determining pH by using a pH meter and electrode.
2.4.3 Interferences
No interferences are known.
2.4.4 Safety
The calibration standards, sample types, and most reagents used in
this method pose no hazard to the analyst. Protective clothing (lab
coat and gloves) and safety glasses must be used when handling
sulfuric acid.
2.4.5 Apparatus and Equipment
2.4.5.1 Orion Model 611 pH meter
-------
Figure 2.8. Schematic of pH measurement system.
O O 3O (/>
Q> Qi CD CD
n> - c+
..(/>_/.
ro -« o
o o 3
»- 3
OK-' ro
-h . ro
oo o
-t* (f>
tn
-------
Section 2.0
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Page 21 of 45
INLET
Figure 2.9. pH sample chamber.
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2.4.5.2 Orion Ross combination pH electrode
2.4.5.3 pH sample chamber
2.4.5.4 60-mL plastic syringes
2.4.5.5 Luer-Lok syringe valves
2.4.6 Reagents and Consumable Materials
2.4.6.1 pH Calibration Buffers (pH 4 and 7)--Commercially available pH
calibration buffers (NBS- traceable) at pH values of 4 and 7.
2.4.6.2 Potassium Chloride (3 M) Dissolve 75 g KC1 in 1 L of water.
2.4.6.3 Stock pH Quality Control Sample Solution (0.100N h^SO^-- Commercially
available certified standard sulfuric acid at a concentration of
0.100N.
2.4.6.4 WaterWater used in all preparations must conform to ASTM speci-
fications for Type I water ASTM D 1193 (ASTM, 1984). It is obtained
from the Millipore Milli-Q water system.
2.4.7 Sample Collection, Preservation, and Storage
Samples are collected and sealed in 60-mL plastic syringes. They are
stored at 4°C until used.
2.4.8 Calibration and Standardization
2.4.8.1 Weekly, calibrate the temperature function of the pH meter and
electrode using a two-point calibration (4°C and room temperature)
following the instructions.
2.4.8.2 Daily, calibrate the pH function of the pH meter and electrode using
a two-point calibration (pH 7 and 4) following the instructions.
2.4.8.3 Copiously rinse the electrode with water. Immerse in 20 ml pH 7
buffer and stir for 30 to 60 seconds. Discard and replace with an
additional 40 ml pH 7 buffer. While the solution is gently stirred,
measure and record the pH.
2.4.8.4 Repeat the preceding step using the pH 4 buffer.
2.4.8.5 Compare the pH values obtained for the pH 7 and 4 buffers to their
certified values. If either observed value differs from the certified
value by more than ±0.02 pH units, repeat the electrode calibration.
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If acceptable results cannot be obtained, replace the electrode.
2.4.9 Quality Control
QC procedures are outlined in Figure 2.10 and are as follows:
2.4.9.1 pH QC Check SampleDaily, prepare a pH QC check sample (pH QCCS)
by diluting 1.000 ml of the 0.100N H2S04 to 1.000 L with water.
2.4.9.2 Initial pH QC CheckImmediately after calibration, analyze the pH
QCCS by using the procedure described in section 2.4.8. The observed
pH must be 4.0 ± 0.1 pH unit. If it is not, repeat the calibration
process, then repeat the measurement on a fresh pH QCCS. If an
acceptable result is still not obtained, consult the troubleshooting
guide which is provided by the manufacturer for the meter and elec-
trode. Samples must not be analyzed until an acceptable value for
the pH QCCS is obtained.
2.4.9.3 Continuing pH QC CheckIn order to check for calibration drift,
the pH QCCS sample is analyzed after every five samples and after the
last sample. The measured valve must be 4.0 ± 0.1 pH unit. If it is
not, recalibrate the electrode and meter and reanalyze all samples
analyzed since the last acceptably analyzed pH QCCS.
2.4.9.4 Duplicate AnalysisTo determine the analytical precision, analyze
one sample per batch in duplicate.
2.4.10 Procedure
2.4.10.1 Calibrate the pH meter and electrode.
2.4.10.2 Perform the required QC analysis. Proceed with sample analyses if
acceptable results are obtained.
2.4.10.3 Clamp a pH sample chamber to a ringstand. Rinse thoroughly with
water.
2.4.10.4 Equilibrate the sample syringes to room temperature.
2.4.10.5 Attach a sample syringe to the sample chamber. Fill the chamber with
sample. Rinse the electrode in the top of the chamber for 15 to 30
seconds. Drain the chamber and repeat. Refill the chamber with
sample and loosely insert the electrode. Flush with 5 to 10 ml
sample to expel air bubbles, then lightly seal the chamber. Measure
and record the sample pH and temperature. Monitor the pH reading.
Record the reading when it stabilizes (± 0.01 pH unit/minute, usually
about 1 to 5 minutes). Slowly inject 5 ml sample over a 60-second
period. Measure the pH and record when stable. Repeat the 5-mL
injections until successive pH readings are within 0.03 pH units.
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Section 2.0
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Perform initial
calibration.
Is QCCS
within 0.1 pH unit?
No
YES
Record on Form 5.
Measure pH
of 5 samples.3
Record on Form 5.
Yes
Record
on
Form 5.
Jes
Is QCCS within 0.1 pH unit?
Record QCCS value
on Form 5 and note
sample ID numbers
associated with
unacceptable QCCS.
No
\
Does enough volume
of previously analyzed \
stream samples remain )
for reanalysis? /
No
I
aMeasure 1 sample per batch in duplicate (same syringe).
bPrevious samples must be reanalyzed after unacceptable QCCS is obtained.
Figure 2.10. Flow scheme for pH determinations.
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2.4.10.6 Rinse the sample chamber and electrode copiously with water between
samples.
2.4.10.7 At the end of the day, store the electrode in 3 M KC1.
2.4.11 Calculations
No calculations are required.
2.4.12 Reporting
Record the raw data in the pH logbook, and record the final sample pH
value on Form 5. Also record the initial and continuing QC results on
Form 5.
2.5 Determination of Turbidity
2.5.1 Scope and Application
This method is applicable to the determination of turbidity in natural
surface waters and is written specifically for the NSWS. Turbidity is
determined in the MPL by using a Monitek Model 21 nephelometer. As a
result, the method has been written with the assumption that the Monitek
nephelometer is used (Monitek, 1977). The applicable turbidity range is
0 to 200 NTU.
2.5.2 Summary of Method
Samples are collected at the stream site in Cubitainers. At the MPL
the sample turbidity is measured directly in NTU by using a calibrated
nephelometer.
2.5.3 Interferences
Air bubbles in the sample cuvette interfere with the determination
and cause a positive bias.
2.5.4 Safety
2.5.4.1 The calibration standards and sample types pose no hazard to the
analyst.
2.5.5 Apparatus and Equipment
2.5.5.1 Monitek Model 21 nephelometer and sample cuvettes
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2.5.6 Reagents and Consumable Materials
2.5.6.1 Turbidity Calibration Standard (10 NTU)Commercially available
certified turbidity standard.
2.5.6.2 Turbidity Quality Control Samples (1.7, 5, 20, 50, 100, and 200
NTU)Commercially available certified turbidity standards.
2.5.7 Sample Collection, Preservation, and Storage
Stream samples are collected in plastic Cubitainers and are stored at
4°C until use.
2.5.8 Calibration and Standardization
2.5.8.1 Turn on the nephelometer power and lamp. Allow to warm up for 15 to
30 minutes.
2.5.8.2 Set the nephelometer range switch to 20. Zero the instrument with
the zero knob.
2.5.8.3 Place the 10.0-NTU calibration standard in the instrument. Calibrate
by setting the reading to 10.0 with the calibrate knob.
2.5.9 Quality Control
QC procedures are outlined in Figure 2.11 and are as follows:
2.5.9.1 Initial Calibration Verification and Linearity CheckImmediately
after calibration, analyze the 1.7-, 5.0-, and 20.0-NTU QC samples
to ensure the calibration validity and linearity. The measured
values must be 1.7 ± 0.3, 5.0 ± 0.5, and 20.0 ± 1.0. If the measured
values are unacceptable, the calibration must be repeated. Ensure
that the instrument is warmed up and that the cuvettes are clean.
Acceptable results must be obtained prior to sample analysis.
2.5.9.2 Continuing Calibration CheckAfter every eight samples and after the
last sample, reanalyze the 5.0-NTU QC sample. The measured value must
be 5.0 ± 0.5 NTU. If it is not, recalibrate the instrument and re-
analyze all samples analyzed since the last acceptably analyzed QC
sample.
2.5.9.3 Duplicate AnalysisIn order to determine the analytical precision,
analyze one sample per batch in duplicate.
2.5.10 Procedure
2.5.10.1 Warm up the nephelometer.
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2.5.10.2 Calibrate the nephelometer.
2.5.10.3 Analyze the QC samples. Proceed with the following sample analysis
if acceptable results are obtained.
2.5.10.4 Allow the sample Cubitainer to reach room temperature. Gently swirl
sample Cubitainers to mix and distribute any particles which may have
settled out during sample transport. Care must be taken to avoid
agitation-induced air bubbles which interfere with the measurement.
Rinse the nephelometer cuvette with two 5-mL portions of sample, then
fill (approximately 25 ml sample). Wipe the cuvette with a Kimwipe,
insert the cuvette into the nephelometer, and measure the turbidity
on range 20. (Note: Fingerprints, bubbles, smudges, etc., must be
avoided because they will affect the accuracy of the system.) The
turbidity of a sample is not expected to exceed 20 NTU; however, if
this occurs, the sample must be analyzed on range 200. In this case,
a QC sample with a turbidity greater than the sample must be analyzed
(50, 100, or 200-NTU QC samples are available). Acceptable results
for the QC samples are 50 ± 2.5, 100 ± 5, and 200 ± 10, respectively.
If an acceptable QC value is not obtained, the turbidimeter must be
recalibrated on range 200 by using a 100-NTU QC standard, and the
sample must be reanalyzed. If the sample turbidity exceeds 200 NTU,
the sample must be diluted 1:10 with filtered sample and must be
reanalyzed on range 200 as stated above. The turbidity of the
original sample is calculated by multiplying the turbidity of the
dilute sample by the dilution factor.
2.5.10.5 Rinse cuvette thoroughly with water between samples.
2.5.11 Calculations
No calculations are required.
2.5.12 Reporting
Record the sample and QC data in the turbidity logbook and on Form 5.
Report only the QC data for the 5.0-NTU QC sample on Form 5.
2.6 Determination of True Color
2.6.1 Scope and Application
This method is applicable to the determination of true color in natural
surface waters and is written specifically for the NSWS. True color is
determined in the MPL by using a Hach Color Determination Kit. As a
result, the method has been written with the assumption that the Hach
Color Determination Kit is used. The applicable color range is 0 to 200
PCU.
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Section 2.0
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YES
Perform initial
calibration.
Range: 20
Cal. Std.: 10 NTU
T
Make calibration linearity
check
1. Analyze 1.7-NTU QC sample
2. Analyze 5-NTU QC sample.
3. Analyze 20-NTU QC sample.
Are measured values
1.7 + 0.3, 5.0 + 0.5,
20.0 + 1.0?
Record values in logbook,
and record value for 5-
NTU standard on Form 5.
V
Analyze up to 8 samples3
Record results in logbook,
Record QC result and
previous sample
results on Form 5.
NO
Check instrument operation,
standard concentrations,
etc.
Samples associated with
unacceptable QC
must be reanalyzed
when acceptable
QC is obtained.
YES / Analyze 5-NTU QC sample.
Is measured value 5 + 0.5 NTU?
NO
\
aAnalyze one sample per batch in duplicate.
Figure 2.11. Flow scheme for turbidity determinations.
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2.6.2 Summary of Method
Samples are collected at the stream site in Cubitainers. At the MPL,
the true color is determined after centrifuging a sample and after
comparing its color to APHA PCU color standards.
2.6.3 Interferences
No interferences are known.
2.6.4 Safety
The sample types pose no hazard to the analyst.
2.6.5 Apparatus and Equipment
2.6.5.1 Hach Model CO-1 Color Determination Kit with sample cuvette.
2.6.6 Reagents and Consumable Materials
2.6.6.1 WaterWater used to rinse cuvettes must conform to ASTM specifica-
tions for Type I water ASTM D 1193 (ASTM, 1984). It is obtained from
the Millipore Milli-Q water system.
2.6.7 Sample Collection, Preservation, and Storage
Streams samples are collected in plastic Cubitainers and are stored at
4°C until use.
2.6.8 Calibration and Standardization
The color kit contains permanent color standards. No calibration is
necessary.
2.6.9 Quality Control
Duplicate AnalysisTo determine the analytical precision, analyze one
sample per batch in duplicate.
2.6.10 Procedure
2.6.10.1 Allow the samples to reach room temperature.
2.6.10.2 Centrifuge a 50-mL sample to remove turbidity. Rinse a sample cuvette
with three 5-mL portions of centrifuged sample. Fill the cuvette
with sample and cap it. Determine the color by using the color kit
and by following the instructions provided by the manufacturer.
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2.6.10.3 Rinse the sample cuvette thoroughly with water between samples.
2.6.11 Calculations
No calculations are necessary.
2.6.12 Reporting
Record the sample data in the color logbook and on Form 5.
2.7 Determination of Nonexchangeable Pyrocatechol Violet (PCV) Reactive and
Total PCV Reactive A1uminu₯
2.7.1 Scope and Application
This method is applicable to the determination of total reactive and
nonexchangeable reactive aluminum species in natural surface waters.
Detection Limits (MDLs) are to be determined. The method is presently
in the developmental stage, and only limited data are available on its
application. A similar manual method was found to have a detection
limit of 3.0 ug Al/L (Dougan and Wilson, 1974). Rogeberg and Henriksen,
1985, reported a minimum detection limit of 10 ug Al/L when use was made
of an automated segmented flow system similar to the one in the present
study. This MDL is identical to that reported for an automated flow
injection analyzer. The method is applicable for determining the various
Al species over the concentration range 0.01 to 0.80 mg Al/L.
This method does not distinguish various inorganic monomeric aluminum
species from each other nor does it distinguish the various neutral
organic complexes of aluminum from each other. Furthermore, the defini-
tions of total monomeric and nonlabile monomeric organic aluminum are
operationally based upon commonly accepted usage. Actually, some charged,
organically complexed aluminum may be measured as inorganic aluminum,
and some strongly complexed aluminum may not be measured in either
fraction.
2.7.2 Summary of Method
Samples are collected in syringes. The aluminum species in each sample
are subsequently determined by flow injection analysis (FIA). Samples
are loaded into the FIA system manually, directly from the syringe, and
are then injected. The sample, carried by a deionized flow stream, is
mixed with hydroxylammonium/l,10-phenanthroline solution to eliminate
iron interference. The sample is next reacted with a pyrocatechol
violet solution. The pH of the solution is then adjusted to pH 6.1 with
buffer. The Al is subsequently quantitated by measuring the absorbance
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of the PCV-A1 complex at 580 nm. The Al so measured is termed total PCV
reactive Al.
Another portion of sample undergoes the same reaction sequence; how-
ever, it is first passed through a strong cation-exchange column prior
to reaction with PCV. The column removes inorganic monomeric Al. The
Al measured after the cation-exchange procedure is termed nonexchange-
able PCV reactive Al. Other organic complexes of aluminum are very
stable and do not react with PCV and are not measured. This fraction
is believed to be nontoxic to fish.
2.7.3 Definitions
Total PCV reactive aluminum (total monomeric aluminum) is defined as the
fraction of aluminum which reacts with pyrocatechol violet without
preliminary acidification. This includes aluminum in the free ionic
form and aluminum which is weakly complexed (compared to pyrocatechol
violet) by inorganic and organic ligands.
Nonexchangeable PCV reactive aluminum is operationally defined as the
fraction of total monomeric aluminum which is not removed by cation-
exchange resins but is reactive with PCV. This fraction includes weakly
complexed organo-alunvinum species (organic monomeric aluminum).
It is theoretically nontoxic and is subtracted from total reactive
aluminum to estimate the inorganic monomeric aluminum concentration
which is believed to be toxic to fish.
2.7.4 Interferences
Holding time and storage methods affect the aluminum speciation in water
samples. Samples should be analyzed as soon as possible after collection.
Samples should be stored at 4°C in the dark during transit. Changes in
temperature and pH may drastically alter aluminum speciation.
Iron (III) interferes with the determination of aluminum when use is made
of this method. The interference is eliminated by reducing Fe (III) to
Fe (II) with hydroxylammonium chloride and subsequently chelating with
1,10-phenanthroli ne.
2.7.5 Safety
The calibration standards and most chemical reagents encountered in this
method pose no hazard to the analyst when good laboratory practices are
followed. Protective clothing (safety glasses, gloves, lab coat) should
be worn when handling concentrated acids and bases.
2.7.6 Apparatus and Equipment
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2.7.6.1 Automated Dual Channel Flow-Injection Analyze)A microprocessor-
controlled system is used for automatic injection of samples, mixing
of the required chemicals for the pyrocatechol violet reaction, and
detection of the aluminum-catechol complex.
2.7.6.2 Cation-Exchange ColumnAn Amberlite IR 120 (14 to 50 mesh) exchange
resin is used to separate the organic monomeric aluminum from the
inorganic monomeric aluminum, by using a 100 mm x 3 mm ID Teflon column
with fritted Teflon inserts containing the resin.
2.7.6.3 Clean-Air Laminar-Flow Hood
2.7.6.4 Nucleopore/Polyearbonate Filters
2.7.6.5 Polystyrene Divinyl Benzene Beads (14 to 50 mesh)--
2.7.7 Reagents and Consumable Materials
2.7.7.1 WaterAll water used in preparing reagents and cleaning labware must
meet the specifications for Type I Reagent Water given in ASTM D 1193
(ASTM, 1984).
2.7.7.2 Stock Reagents
Ethanol - 95 percent (Reagent).
Hydrochloric acid (HC1) - concentrated (Baker Ultrex grade or
equivalent).
Sodium Chloride - crystal (ACS reagent grade).
Ammonium hydroxide (NH4OH) - concentrated (Baker Instra-Analyzed or
equivalent).
Nitric Acid - concentrated (Ultrex grade or equivalent).
0.1 M HC1 - slowly add 8.3 ml concentrated HC1 acid to 500 ml water
and dilute to 1.00 L mark.
Cleaning solution (0.1 N HC1 in 10 percent ethanol) - Slowly add 8.3 mL
concentrated HC1 to 500 ml D.I. water in a 1-L graduated cylinder.
Then add 100 mis ethanol and bring to a final volume of 1.00 L with
D.I. water. Prepare under fume hood.
10 percent nitric acid (1.6 N) - Slowly add 10 ml concentrated Ultrex
nitric acid to 50 ml of water. Dilute to 100 ml with water.
Sodium chloride solution (0.001 M Nad) - Dissolve 0.058 g sodium
chloride (ACS reagent grade) in water and dilute to 1.00 L.
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2.7.7.3 Working Reagents-
Reagent Rl (masking solution) - dissolve 7.6 g hydroxylammoniurn
chloride and 0.56 g 1,10-phenanthroline in 600 ml water and dilute to
1.000 L. Degas and store in clean polyethylene bottle.
Reagent R2 (pyrocatechol violet solution) - dissolve 0.375 g pyro-
catechol violet in 400 ml water. Let solution stand for about 5
minutes with occasional shaking, then dilute to 1.00 L. Store in
acid-washed, water-rinsed polyethylene bottle. Degas before use.
Reagent R3 (buffer) - dissolve 78 g hexamethylenetetraamine in 750 ml
water and dilute to 1 L. Mix well, degas, and transfer the solution
to a polyethylene bottle.
Ion-exchange resin - mix the sodium form of the Amber!ite IR 120 (14
to 52 mesh) resin with 1 percent of the corresponding hydrogen form.
Wash the resin twice with water and then with 0.001 M NaCl until the
supernatant is clear. Pack column daily with fresh Amberlite resin.
NOTE: Reagents Rl, R2, and R3 must be prepared daily.
2.7.7.4 Aluminum Calibration Standards--
Stock aluminum calibration solution (1,000 mg Al/L) - Commercially
available certified standard.
Dilute stock aluminum calibration solution (10 mg Al/L) - Add, using
a volumetric pipet, 10.0 mL of the 1,000 mg Al/L solution to 750 mL
water containing 1.0 mL 10 percent nitric acid in a 1.0 liter volumetric
flask, then dilute to the mark with water.
Dilute calibration standards - Daily, prepare the calibration stan-
dards listed in the table by diluting the appropriate volume of 10.0
mg Al/L standard solution to 100 mL. Dispense using volumetric pipets.
Low Calibration
High Calibration
Standard
Concen-
tration (mg/L)
0.0000
0.0250
0.1000
0.2000
0.3500
mL 10.0
mg Al/L
Required
0.000
0.250
1.000
2.000
3.500
Standard
Concen-
tration (mg/L)
0.3500
0.5000
0.7500
1.0000
mL 10.0
mg Al/L
Required
3.500
5.000
7.500
10.000
TOTE: Prepare the blank (0.000 mg Al/L) by adding tf.OZU ml 10 percent
nitric acid to 50 mL water in a 100-mL volumetric flask. Dilute
to 100 mL with water.
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2.7.7.5 Aluminum Quality Control Samples--
Stock aluminum QC solution (1,000 mg Al/L) - Commercially available
certified standard from a source independent of the calibration
standard.
Dilute QC stock aluminum solution (10 mg Al/L) - Prepare as in section
2.7.7.4.
Detection limit QC sample (0.020 mg Al/L) - Daily, add 0.0200 mL 1,000
mg Al/L QC solution to 100 mL water then dilute to 1.000 L.
Routine QC sample (0.0750 mg Al/L) - Daily, add 3.75 mL 10.00 mg Al/L
QC solution to 100 mL water then dilute to 500.00 mL.
2.7.7.6 Syringe Filters--
Acid-wash sufficient 25-mm Swin-Lok filter holders with 5 percent
nitric acid. Rinse thoroughly with water.
Using clean Teflon forceps, remove a 25-mm Nucleopore polycarbonate
filter from the package. Dip filter into beaker of water to prewet
the filter.
Place filter on the filter base. Place filter base with filter on
syringe attachment. Center o-ring on filter and place filter top on
o-ring. Compress o-ring by screwing exit port onto syringe attachment.
Attach a syringe containing 5 percent nitric acid onto the Luer-Lok
fitting. Inject 1 to 2 mL through the filter unit. Attach another
syringe containing water and inject three separate aliquots of 10 to
15 mL through the filter unit.
Repeat the above procedure to prepare adequate filter units for daily
batch analysis. Store acid-washed syringe filters in self-sealing
bags until needed.
2.7.8 Sample Collection, Preservation, and Storage
Samples are collected in 60-mL syringes with syringe lock valves to
prevent C02 degassing or adsorption.
Samples are stored at 4°C in the dark.
2.7.9 Calibration and Standardization
Channel 1 (Reactive Aluminum)--Analyze the low and high calibration
standards (including the 0.00 mg/L standard) before each shift. A
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calibration curve is generated by plotting standard response versus
standard concentration. Alternatively, the best fit line of response
versus concentration is calculated (by the data system of the FIA) by
linear regression.
Channel 2 (Nonexchangeable Reactive Aluminum)--Replace the ion-exchange
column in the FIA system channel 2 with a blank column containing poly-
styrene divinyl benzene resin beads (same mesh size as ion-exchange
resin). Analyze the low and high standards and generate a calibration
curve as in the Channel 1 calibration.
2.7.10 Quality Control
Internal Quality Control
MPL Duplicate - analyze one sample per batch in duplicate. The RSD for
duplicate results must be less than or equal to 10 percent. If it is
not, the reason for the poor precision must be found and eliminated
prior to continuing sample analysis.
Detection Limit Quality Control Check Sample - analyze the detection
limit QCCS immediately after calibration and prior to sample analysis.
The measured concentration must be within 20 percent of the actual
concentration. If not, the reason for the poor accuracy must be found
and eliminated prior to sample analysis.
Routine Quality Control Check Sample - analyze the routine QCCS after
the detection limit QCCS, after every fifth sample, and after the final
sample. The observed concentration should be within 10 percent of the
actual concentration. If this is not the case, the reason for the poor
accuracy must be found and eliminated before continuing sample analysis.
If necessary, the FIA must be recalibrated. All samples analyzed since
the last acceptable QCCS must be reanalyzed.
2.7.11 Procedure
2.7.11.1 System PreparationSet up both channels of the FIA system as
illustrated in Figures 2.12 and 2.13. Program the computer according
to instructions provided by the manufacturer.
2.7.11.2 Fill unused syringes with the calibration standards and QC samples.
2.7.11.3 Sample Analysis--
Standard and QC sample analysis (channel 1 - Reactive Al) - manually
load the sample injection loop and then inject to start the FIA
analysis.
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C.
R1.
R2.
R3.
ml/min SA^PLE
1.8
0.8
0.8
1.0
RC1 RC2 RC3
pH6.1
(waste)
Key:
CarrierDaionixed water (or 0.1 M HCI)
R1 Masking solution : Hydroxylammonium chloride
and 1.10 Phenanthroline chloride
R2 Color reagent: Pyrocatecholviolet
R3 Buffer solution : Hexamethylenetetramine and NaOH
RC1 Reaction coil, 10 cm (0.6 mm i.d.)
RC2 Reaction coil. 30 cm (0.5 mm i.d.)
RC3 Reaction coil. 60 cm (0.5 mm i.d.)
Figure 2.12. Channel one schematic for total PCV reactive Al.
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C.
R1.
R2.
R3.
Sample-
ml/min
1.8
0.8
0.8
1.0
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>Waste
CEC
RC1 RC2 RC3
pH6.1
(waste)
Carrier: Deionized water (or 0.1 M HCI)
R1 Masking solution : Hydroxylammonium chloride
and 1.10 Phenanthroline chloride
R2 Color reagent: Pyrocatecholviolet
R3 Buffer solution : Hexamethylenetetramine and NaOH
RC1 Reaction coil, 10 cm (0.6 mm i.d.)
RC2 Reaction coil. 30 cm (0.5 mm i.d.)
RC3 - Reaction coil. 60 em (0.6 mm i.d.)
CEC Cation exchange column
Figure 2.13. Channel two schematic for nonexchangeable PCV reactive Al.
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Standard and QC sample analysis (channel 2 - Nonexchangeable Al) -
manually load the sample injection loop, then inject to start the FIA
analysis.
Routine sample analysis - place a 0.4-um polycarbonate syringe filter
on the sample syringe. Eject 5.0 ml sample through the filter into a
waste container. Next, load the sample injection loop with filtered
sample and inject to start the FIA analysis.
2.7.11.4 Analyze the routine QC sample every five samples and after the last
sample. Results must be within the specifications listed in section
2.7.10.
2.7.11.5 If a sample concentration exceeds the calibrated range, inject a
smaller sample volume (consult the operating manual for details on
techniques to reduce sample volume).
2.7.11.6 Replace the ion-exchange cartridge after every 50 samples injected.
2.7.11.7 After a day's analysis, flush the FIA system with water for 5
minutes and then flush with air for 2 minutes.
2.7.12 Calculations
Calculate concentration by comparing the peak heights with the calibra-
tion curve. Report results as ug Al/L for both species of aluminum.
2.7.13 Precision and Accuracy
For surface water samples containing 10 to 350 ug Al/L, the average
standard deviation was ±3.1 ug Al/L.
Accuracy (recovery) was reported by Rogeberg and Henriksen, 1985, for
surface waters spiked with 150 and 580 ug Al/L. The recovery was found
to be to be 99 percent and 105 percent, respectively.
2.8 Aliquot Preparation
2.8.1 Summary
Stream samples are collected in 4-L Cubitainers. From each sample, the
aliquots are prepared. Each aliquot is processed in a different manner
according to which analytes will be determined in the aliquot.
A brief description of the aliquots is given in Table 2.3.
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TABLE 2.3. ALIQUOT DESCRIPTIONS
Aliquot
1
2
3
4
5
6a
7
8»
Container Description
250 mL
(acid-washed)
10 mL
(acid-washed)
250 mL
(not acid-washed)
125 mL
(acid-washed)
500 mL
(not acid-washed)
125 mL
(acid-washed)
125 mL
(acid-washed)
10 mL
Description
Filtered sample acidified with HN03 to
a pH <2
MIBK-Hydroxyquinoline extract
Filtered sample
Filtered sample acidified with ^$04
to a pH <2
Raw unfiltered sample
Filtered sample acidified with HoSO,
to a pH <2
Unfiltered sample acidified with HN03
to a pH <2
MIBK-Hydroxyquinoline extract
aUnfiltered for Pilot study.
bFor Streams Pilot only. See 2.8.5.5.
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2.8.2 Safety
The sample types and most reagents used in preparing aliquots pose
little hazard to the analyst. Protective clothing (lab coat and gloves)
and safety glasses must be used when handling concentrated sulfuric,
nitric, hydrochloric, and glacial acetic acids and concentrated ammonium
hydroxide. The use of hydrochloric and acetic acids and of ammonium
hydroxide should be restricted to the hood.
MIBK is a highly flammable organic solvent and must be kept away from
ignition sources. Also, MIBK vapor is irritating to the eyes, nose, and
throat. Exposure to the vapor may cause temporary irritation.
Liquid MIBK is also an irritant. If spilled on skin or in eyes, wash
affected area thoroughly with water until irritation stops. The use of
MIBK should be restricted to the hood. If it must be used outside of
the hood, organic vapor masks should be worn.
2.8.3 Apparatus and Equipment
Filtration ApparatusIncludes filter holder, vacuum chamber, and vacuum
pumps.
2.8.4 Reagents and Consumable Materials
2.8.4.1 Ammonium Hydroxide (1 M)Carefully add 20 ml concentrated ammonium
hydroxide (NH4OH, 5 M, Baker Instra-Analyzed grade or equivalent) to
80 ml water.
2.8.4.2 Glacial Acetic AcidBaker Instra-Analyzed grade or equivalent.
2.8.4.3 8-hydroxyquinoline Solution (10 g/L)--Dissolve 5 g 8-hydroxyquinoline
(99 percent plus purity) in 12.5 ml glacial acetic acid (HOAc, Baker
Instra-Analyzed grade or equivalent), then dilute to 500 ml with
water.
2.8.4.4 8-hydroxyquinoline/Sodium Acetate Reagent (HOx Reagent)Prepare
daily by mixing in order, 30 ml 1.0 M NaOAc, 150 ml water, and 30 mL
8-hydroxyquinoline solution.
2.8.4.5 Buffer Solution (pH 8.3)Carefully add 56 mL glacial acetic acid
(Baker Instra-Analyzed grade or equivalent) to 75 mL NH4OH (5 M,
Baker Instra-Analyzed grade or equivalent). Dilute to 250 mL with
water. Adjust the pH to 8.3 with NH4OH or HOAc (whichever is neces-
sary, testing the pH with indicating pH paper). Add an additional 16
mL NH4OH, then dilute to 500 mL with water.
2.8.4.6 Nitric Acid (HN03, 12 M, Baker Ultrex grade or equivalent).
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2.8.4.7 Phenol Red Indicator Solution (4 percent w/v).
2.8.4.8 Sodium Acetate (NaOAc, 1.0 M)Dissolve 8.20 g sodium acetate (Alfa
ultrapure grade or equivalent) in water, then dilute to 100 ml.
2.8.4.9 Sulfuric Acid (^$04, 18 M, Baker Ultrex grade or equivalent).
2.8.4.10 WaterWater used in all preparations must conform to ASTM specifica-
tions for Type I water ASTM D 1193 (ASTM, 1984). It is obtained from
the Mi Hi pore Milli-Q water system.
2.8.4.11 Aliquot BottlesClean aliquot bottles are required for the aliquots
prepared from each sample. The bottles are cleaned (by using the
procedure in Appendix A) and are supplied by an outside contractor.
2.8.4.12 Indicating pH Paper (Range 8 to 9 and 1 to 3)
2.8.4.13 Membrane Filters (0.45-nm pore size)
2.8.5 Procedure
Preparation of the aliquots is described in this section. All filtra-
tions and aliquot 2 preparation are performed in the laminar-flow clean
work station.
2.8.5.1 Preparation of Aliquots 1, 4, and 6 (Unfiltered for Pilot Study)
Complete aliquot labels for aliquots 1, 4, and 6 and attach to
containers. Assemble the filtration apparatus with a waste container
as a collection vessel. Thoroughly rinse the filter holder and
membrane filter in succession with 20 to 40 ml water, 20 ml 5 percent
HN03 (Baker Instra-Analyzed grade), and 40 to 50 ml water.
Rinse the filter holder and membrane with 10 to 15 mL of the sample
to be filtered.
Replace the waste container with the aliquot 1 container. Reapply
vacuum (vacuum pressure must not exceed 12 in. Hg), and filter 10 to
15 mL of sample. Remove the vacuum. Rinse the aliquot 1 container
with the 15 ml of filtered sample by slowly rotating the bottle so
that the sample touches all surfaces. Discard the rinse sample and
replace the container under the filter holder.
Filter sample into the container until full.
Transfer filtered sample into the aliquot 4 and 6 containers (pre-
viously labeled) after first rinsing the containers with 10 to 15 mL
filtered sample.
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Return the aliquot 1 container to the filtration apparatus and
collect additional filtered sample until the container is full.
If it is necessary to replace a membrane (because of clogging) before
adequate filtered sample has been obtained, rinse the new membrane
with 15 to 20 ml water, 10 to 15 ml 5 percent HN03, 40 to 50 mL
water, and 10 to 15 ml sample prior to collecting additional sample.
Between samples, remove the membrane and thoroughly rinse the filter
holder with water.
Preserve by adding concentrated HN03 to aliquot 1 and concentrated
H2S04 to aliquots 4 and 6 in 0.100-mL increments until the pH <2
(U.S. EPA, 1983). Check the pH by placing a drop of sample on
indicating pH paper, using a clean plastic pi pet tip. Record on the
aliquot label the volume of acid added.
Store aliquots 1, 4, and 6 at 4°C until ready to ship.
2.8.5.2 Preparation of Aliquot 2 - Total Extractable Aluminum
Obtain a filtered portion of sample from the analyst performing
filtrations.
Rinse a clean, plastic 50-mL graduated centrifuge tube with three
10-mL portions of the filtered sample, then fill to the 25.0-mL mark.
Add two to three drops phenol red indicator, 5.0 ml HOx reagent, and
2.0 ml NH4+/NH3 buffer. Shake for 5 seconds. This should adjust the
pH to 8.3, and the solution should turn red. If it does not turn red,
rapidly adjust the pH by dropwise addition of 1 M NfyOH until the
solution color changes to red. Add 10.0 ml MIBK, cap, and shake
vigorously for 10 seconds by using a rapid, end-to-end motion. (Note:
Successful extraction depends on good agitation.) This entire process
should take about 15 to 20 seconds. Open tube carefully after shaking
because pressure builds up.
Centrifuge the sample to hasten separation of the aqueous and organic
layers, then transfer the MIBK layer with a 5-mL micropipet to a
10-mL centrifuge tube. Securely cap tube.
Complete a label for aliquot 2 and attach label to the container.
Store the 10-mL tube containing aliquot 2 at 4°C in the dark until
ready to ship.
Discard the 50-mL centrifuge tube after a single use.
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2.8.5.3 Preparation of Aliquot 3Filtered sample for aliquot 3 is obtained
similarly to that for aliquots 1, 4, and 6, except that the filter
holder used to filter aliquot 3 is never allowed to come into contact
with nitric acid. This is CRUCIAL in preventing nitrate contamina-
tion. Previous experience indicates that even the most scrupulous
water rinses did not remove all traces of a nitric acid rinse.
Blanks still contained measurable nitrate.
Soak filter holders for 24 hours in deionized water prior to first
use.
Complete an aliquot 3 label and attach label to the aliquot bottle.
Assemble the filtration apparatus with a waste container as a
collection vessel. Thoroughly rinse the filter holder and membrane
filter with three 25-mL portions water, followed by 10 to 15 ml
sample to be filtered.
Replace the waste container with the aliquot 3 container and filter
an additional 15 ml sample. Remove the container and rinse by slowly
rotating the bottle so that the sample touches all surfaces. Discard
the rinse sample and replace the container under the filter holder.
Filter sample into the container until full.
If it is necessary to replace a membrane (because of clogging), rinse
the membrane with three 20-mL portions water followed by 15 ml sample
before collecting additional sample.
Store at 4°C until ready to ship.
Between samples, remove the membrane and thoroughly rinse the filter
holder with water.
2.8.5.4 Preparation of Aliquots 5 and 7Aliquots 5 and 7 are unfiltered
aliquots.
Complete aliquot 5 and 7 labels and attach to the appropriate aliquot
bottles. Transfer 15 to 20 ml sample to aliquot bottle and rinse by
slowly rotating bottle so that sample touches all surfaces. Discard
rinse.
Fill aliquot bottle with unfiltered sample. Fill aliquot 5 bottle so
that no headspace exists.
Preserve by adding concentrated HN03 to aliquot 7 in 0.100-mL incre-
ments until pH <2 (U.S. EPA, 1983). Check the pH by placing a drop
of sample on indicating pH paper, using a clean plastic pi pet tip.
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Record the volume of acid added on the aliquot label.
Store at 4°C until ready to ship.
2.8.5.5 Aliquot 8 Preparation (Extractable Organic Aluminum) Stream Pilot
Only-
Aliquot 8 is prepared as soon as possible. Furthermore, it is only
prepared for samples with an initial pH <6 (as determined from field
data). As with Aliquot 2, Aliquot 8 must be prepared in the laminar-
flow hood.
Prepare the resin column by pouring the resin slurry into a column
until there is a 10-mL resin bed. Top up the column with 3 x 10~4 M
Nad and connect the column to the peristaltic pump.
Pump 3 x 10~4 M Nad through the column and adjust the flow rate to
40.0 mL/min. Flush the column with 50 mL of the eluent. Check the
eluent pH. It must be 5.0 ± 0.5. If not, reprepare the resin slurry
and column.
Pump 50 ml of sample through the column, collecting the column
effluent in a waste container. Pump an additional 25 to 30 ml sample
through the column, collecting the effluent in a clean 50-mL centri-
fuge tube.
Adjust the volume in the tube to 25.0 ml. Extract the 25.0 ml by using
the same procedure as for Aliquot 2. Attach an Aliquot 8 label,
recording the necessary information. Store at 4°C until ready to
ship.
Flush the column with 50 ml of eluent. Check the effluent pH. It
must be 5.0 ± 0.5. If not, reprepare the column before processing
another sample.
NOTE: Keep resin covered with liquid. Avoid the introduction of air
into the column.
2.9 References
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water, D
1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
Dougan, W. K., and A. L. Wilson, 1974. The Absorptiometric Determination
of Aluminum in Water: A Comparison of Some Chromagenic Reagents and
the Development of an Improved Method. Analyst, v. 99, pp. 413-430.
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Hagley, C. A., C. M. Knapp, C. L. Mayer, and F. A. Morris, 1986. The
National Surface Water Survey Stream Survey (Pilot Middle-Atlantic
Phase I, Southeast Screening, and Middle-Atlantic Episode Pilot)
Field Training and Operations Manual.
Monitek, Inc., 1977. Model 21 Laboratory Nephelometer, Preliminary
Operating and Maintenance Instructions. Hayward, California.
Orion Research Incorporated, 1983. Instruction Manual - Model 611 pH/
mi Hi-volt manual. Orion, Cambridge, Massachusetts.
Rogeberg, E. J. S., and A. Henriksen, 1985. An Automatic Method for
Fractionation and Determination of Aluminum Species in Fresh-Waters,
Vatten, v. 41, pp. 48-53.
U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes. EPA-600/4-79-020. U.S. EPA,
Cincinnati, Ohio.
Xertex-Dohrman Corporation, 1984. DC-80 Automated Laboratory Total
Organic Carbon Analyzer Systems Manual, 6th ed. Xertex-Dohrman,
Santa Clara, California.
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3.0 ANALYTICAL LABORATORY OPERATIONS
3.1 Summary of Operations
Samples are shipped from the MPL to the contract analytical laboratories
for analysis. Each sample consists of seven (eight for Stream Pilot)
aliquots, each processed in a different manner depending on the analytes
for which the aliquot will be analyzed. A brief description of each
aliquot and of corresponding analytes are given in Table 3.1.
After receipt, the analytes in each sample are quantified. The analyses
must occur within the prescribed holding times (Table 3.2) or a penalty is
assessed against the lab. Strict QC requirements must be followed through-
out the analyses. Finally, the sample results must be reported in the
proper format, on a timely basis, for entry in the NSWS data base.
3.2 Sample Receipt and Handling
Samples are shipped to the contract laboratory by overnight delivery
service. Upon receipt, measure the temperature inside the shipping con-
tainer and record the temperature on the shipping form. Log in samples
and ensure that the samples listed on the shipping form have actually been
received. Note anything unusual (such as leaking samples) on the shipping
form.
Store sample aliquots 2, 3, 4, 5, and 6 in the dark at 4°C when not in
use. The samples must be stored at 4°C for 6 months or until notified by
the QA manager.
Clean all labware that comes into contact with the sample (such as
autosampler vials, beakers, etc.) as described in Appendix A.
3.3 Sample Analysis
The analytes to be determined in each sample and corresponding measurement
techniques are listed in Table 3.3, and the method protocols are provided
in sections 4 through 13. Each analyte must be determined within the
holding times listed in Table 3.2.
3.4 Internal Quality Control Requirements
QC is an integral part of sample analysis. Method QC requirements common
to all methods are detailed in this section. QC requirements specific to
a single method are detailed in the description for that method.
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TABLE 3.1. LIST OF ALIQUOTS, CONTAINERS, PRESERVATIVES,
AND CORRESPONDING PARAMETERS TO BE MEASURED
Aliquot3 Container
Preservative and
Description
Parameters
1 250 mL Filtered, pH <2 with HN03
2 10 mL MIBK-HQ extract
3 250 mL Filtered
4 125 mL Filtered, pH <2 with H2S04
5 500 mL Unfiltered
6b 125 mL Filtered, pH <2 with H2S04
7 125 mL Unfiltered, pH <2 with HN03
8C 10 mL MIBK-HQ extract
Ca, Mg, K, Na, Mn, Fe
Total extractable Al
Cl, F, $04, N03, Si02
DOC, NH4
pH, BNC, ANC, specific
conductance, DIC
Total dissolved P
Total Al
Extractable organic Al (ion
exchanged)
aAliquots 2, 3, 4, 5, and 6 must be stored at 4°C in the dark.
bUnfiltered for Pilot Study.
cAliquot 8 is used for the Pilot Study only.
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TABLE 3.2. LIST OF HOLDING TIMES
Maximum
Holding
Time Parameter
7 days N03,a pHb, Total extractable Al
14 days ANC, BNC, specific conductance, DIG, DOC
28 days Total P, NH4> Cl, S04, F, Si02
6 months0 Ca, Mg, K, Na, total Al, Mn, Fe
aAlthough the EPA (U.S. EPA, 1983) recommends that nitrate in unpreserved
samples (un-acidified) be determined within 48 hours of collection, evidence
exists (Peden, 1981 and APHA et al.. 1985) that nitrate is stable for 2 to 4
weeks if stored in the dark at 4°C.
b Although the EPA (U.S. EPA, 1983) recommends that pH be measured immediately
after sample collection, evidence exists (McQuaker et al., 1983) that it is
stable for up to 15 days if stored at 4°C and sealed from the atmosphere.
The pH is also measured in a sealed sample at the field station within 12
hours of sample collection.
CA1though the EPA (U.S. EPA, 1983) recommends a maximum 6-month holding time
for these metals, this study requires that all of the metals be determined
within 28 days. This is to ensure that significant changes do not occur and
to obtain data in a timely manner.
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TABLE 3.3. LIST OF PARAMETERS AND CORRESPONDING MEASUREMENT METHODS
Parameter
Method
1. BNC
2. ANC
3. Aluminum,
4. Aluminum,
total
total
extractable
5. Aluminum, Nonexchangeable and
Total PCV Reactive
6. Ammonium, dissolved
7. Calcium, dissolved
8. Chloride, dissolved
9. Fluoride, total dissolved
10. Inorganic carbon, dissolved
11. Iron, dissolved
12. Magnesium, dissolved
13. Manganese, dissolved
14. Nitrate, dissolved
15. Organic carbon, dissolved
16.
17.
PH
Phosphorus,
total dissolved
18. Potassium, dissolved
19. Silica, dissolved
20. Sodium, dissolved
21. Sulfate, dissolved
22. Specific conductance
Titration with Gran analysis
Titration with Gran analysis
202.2 AAS (furnace)
Extraction with 8-hydroxyquinoline
into MIBK followed by AAS (furnace)
Automated Colorimetric Pyrocatechol
Violet (PVC)
Automated colorimetry (phenate)
AAS (flame) or ICPES
Ion chromatography
Ion-selective electrode and meter
Instrument (acidification, C02
generation, IR detection)
AAS (flame) or ICPES
AAS (flame) or ICPES
AAS (flame) or ICPES
Ion chromatography
Instrument (uv-promoted oxidation,
C02 generation, IR detection)
pH electrode and meter
Automated colorimetry
(molybdate blue)
AAS (flame)
Automated colorimetry
(molybdate blue)
AAS (flame)
Ion chromatography
Conductivity cell and meter
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3.4.1 Method Quality Control
Each method contains specific QC steps which must be performed to
ensure data quality. Table 3.4 is a brief summary of the required
QC checks as well as control limits and corrective actions for QC
checks outside control limits. QC steps common to all (or most) of
the methods are detailed in sections 3.4.1.1 through 3.4.1.5, while
QC steps specific to a single method are detailed in the method
protocol.
3.4.1.1 Calibration Verification QC Check SampleAfter performing the cali-
bration step for a method, verify the calibration (to ensure proper
standard preparation, etc.) prior to sample analysis by analyzing a
calibration QC check sample (QCCS). The QCCS is a known sample
containing the analyte of interest at a concentration in the low- to
mid-calibration range. Furthermore, the QCCS must be independent of
the calibration standards.
For each batch of samples, analyze the calibration QCCS immediately
after calibration, after every 10 sample analyses, and after the
final sample analysis. Plot the measured analyte concentration in
the QCCS on a control chart and develop the 95 percent and 99 percent
confidence intervals. The 99 percent confidence interval must be
within the limits given in Table 3.5. (The limits in Table 3.5 may
be used as initial limits until enough data are obtained to generate
a control chart.) If the 99 percent confidence interval is not with-
in those limits, a problem exists with the experimental technique or
the QCCS itself.
The measured analyte concentration in the QCCS must be within the 99
percent confidence interval. An acceptable result must be obtained
prior to continuing sample determinations. If unacceptable results
are obtained, repeat the calibration step and reanalyze all samples
analyzed since the last acceptably analyzed QCCS.
3.4.1.2 Detection Limit Determination and VerificationDetermine the
detection limit weekly for all parameters (except pH and specific
conductance for which the term detection limit does not apply). For
the NSWS, the detection limit is defined as three times the standard
deviation of 10 nonconsecutive reagent or calibration blank analyses.
In the case where a signal is not obtained for a blank analysis (such
as in ion chromatographic analyses or autoanalyzer analyses), a low-
concentration standard (concentration about three to four times the
detection limit) is analyzed rather than a blank. Detection limits
must not exceed the values listed in Table 1.1. If a detection limit
is not met, refine the analytical technique and optimize any instru-
mentation variables until the detection limit is achieved.
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TABLE 3.4. SUMMARY OF INTERNAL METHOD QUALITY CONTROL CHECKS
****
Parameter or Method QC Check Control Units Corrective Action*
BMC. ANC, pH 1. Tltrtnt standardization cross- 1. Relative difference 60S. 6. Clean or replace separator
~ column. Recalibrate.
Assuming QC check is outside control limits.
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TABLE 3.5. MAXIMUM CONTROL LIMITS FOR QUALITY CONTROL SAMPLES
Maximum Control Limit for QC Sample (% Deviation from
Parameter Theoretical Concentration of QC Sample)
Al, total extractable ±20%
Al, total ±20?
Ca ±5?
Cl ±5%
DIC ±10%
DOC ±10%
F, total dissolved ±5%
Fe ±10%
K ±5%
Mg ±5%
Mn ±10%
Na ±5%
NH4 ±10%
N03 ±10%
P, total dissolved ±20%
Si02 ±5%
$04 ±5%
Specific conductance ±2%
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To verify the detection limit for the determination of metals and
total dissolved P daily, analyze a detection limit QCCS after cali-
bration and prior to sample analysis. The detection limit QCCS must
contain the analyte of interest at two to three times the detection
limit. The measured concentration must be within 20 percent of the
true concentration. If it is not, the detection limit is question-
able.
3.4.1.3 Blank AnalysisOnce per batch analyze a calibration blank as a
sample. The calibration blank is defined as a "0" mg/L standard
(contains only the matrix of the calibration standards). The measured
concentration of the calibration blank must be less than twice the
instrumental detection limit. If not, the blank is contaminated, or
the calibration is in error at the low end. Prior to sample analysis,
investigate and eliminate any contamination source and repeat the
calibration.
Prepare and analyze a reagent blank for the three methods which
require sample preparation (dissolved Si Op, total dissolved P, and
total Al). A reagent blank contains all the reagents (in the same
quantities) used in preparing a real sample for analysis. Process in
the same manner (digestions, etc.) as a real sample. The measured
concentration of the reagent blank must be less than twice the
required detection limit (Table 1.1). If it is not, the reagent
blank is contaminated. Investigate and eliminate the contamination
source. Prepare and analyze a new reagent blank and apply the same
criteria. Reanalyze all samples associated with the contaminated
blank when the contamination is eliminated. Contact the QA manager
if a contaminated reagent blank problem cannot be rectified.
Prepare one reagent blank with each set of samples processed at one
time. For example, if two sample batches are processed together,
only one reagent blank is necessary. Report the concentration of the
single reagent blank for both batches. On the other hand, if a
sample batch is split into groups that are processed at different
times, a reagent blank is necessary for each group. In this case,
report all reagent blank values for the batch. (Identify in a cover
letter which reagent blank values are associated with which samples.)
3.4.1.4 Duplicate Sample AnalysisPrepare and analyze one sample per batch
in duplicate. If possible, for duplicate analysis choose a sample
containing analyte at a concentration greater than five times the
detection limit. Calculate the relative standard deviation (RSD)
between duplicates. The duplicate precision (RSD) must not exceed
the value given in Table 1.1. If duplicate RSD values fall outside
the values given in Table 1.1, a problem exists (such as instrument
malfunction, calibration drift, etc.). After finding and resolving
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the problem, analyze a second sample in duplicate. Acceptable dupli-
cate sample results must be obtained prior to continuing sample
analysis.
S
ZRSD = x 100
x
- x)2\l/2
S =
n-1
3.4.1.5 Matrix Spike Analysis (Stream Pilot only)--Prepare one matrix spike
with each batch by spiking a portion of a sample with a known
quantity of analyte. The spike concentration must be the larger of
two times the endogenous level or ten times the required detection
limit. Also, the volume of the spike added must be negligible (less
than or equal to 0.001 of the sample aliquot volume). Calculate the
percent recovery of the spike as follows:
(measured measured \
:oncentration concentration]
of sample " of unspiked I
plus spike sample /
X 100
(actual concentration of spike added)
The spike recovery must be 100 ± 15 percent. If the recovery is not
acceptable, spike and analyze two additional, different samples. If
either recovery is unacceptable, analyze the entire batch by the
method of standard additions. The method of standard addition
involves analyzing the sample, sample plus a spike at about the
endogenous level, and sample plus a spike at about twice the endo-
genous level.
NOTE: Matrix spikes for graphite furnace atomic absorption spectroscopy
(GFAA) analyses may not be added directly in the furnace.
The concentration of the matrix spike must not exceed the instru-
ment linear dynamic range. For this reason, the matrix spike
concentration for furnace analyses must be chosen judiciously and
may be different than suggested above.
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Similarly, care must be taken to avoid exceeding the linear range
when performing standard additions for GFAA analyses. The
samples may be diluted, and the spike levels may be adjusted so
that the linear range is not exceeded.
3.4.2 Overall Internal Quality Control
Once each parameter in a sample has been determined, two procedures
exist for checking the correctness of analyses. These procedures are
outlined in sections 3.4.2.1 and 3.4.2.2.
3.4.2.1 Anion-Cation BalanceTheoretically, the acid neutralizing capacity
(ANC) of a sample equals the difference between the concentration
(eq/L) of cations and the anions in a sample (Kramer, 1982). In
practice, this is rarely true because of analytical variability and
because of ions that are present but not measured. For each sample,
calculate the percent ion difference UID) as follows:
ANC + Z anions - I cations
% Ion Difference = - x 100
TI
TI (Total ion strength) = Z anions + Z cations + ANC + 2 [H+]
Z anions = [Cl"] + [F~] + [N03~] + [S042~]
Z cations = [Na"1"] + [K+] + [Ca2+] + [Mg2+] + [NH4+]
ANC = [ALK]
[H+] = (10~PH) x 106 ueq/L
All concentrations are expressed as microequivalents/liter (ueq/L).
Table 3.6 lists factors for converting mg/L to ueq/L for each of the
parameters.
The %ID must not exceed the limits given in Table 3.7. An unaccept-
able value for %ID indicates the presence of unmeasured ions or an
analytical error in the sample analysis. For the surface waters
sampled, the ions included in the %ID calculation are expected to
account for 90 to 100 percent of the ions in a sample. Note that the
ANC term in the calculation accounts for protolyte ions that are not
specifically determined (such as organic acids and bases).
Examine the data from samples that do not meet the %l\) criteria for
possible causes of unacceptable %ID. Often, the cause is improper
data reporting (misplaced decimal point, incorrect data reduction,
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TABLE 3.6 FACTORS TO CONVERT mg/L TO ueq/L
SS«SSStZ«««««~~~~~« ~2£2'S2SS»!Z«SSZISS3S«««»«S
Factor
Ion (ueq/L per mg/L)
Ca2+
cr
F-
K+
Mg2+
Na+
NH4+
N03"
S042'
49.9
28.2
52.6
25.6
82.3
43.5
55.4
16.1
20.8
switched sample ID'S, etc.). After examining the data, redetermine
any parameter that is suspect. If an explanation for the poor IID
cannot be found and if the problem cannot be corrected, contact the QA
manager at EMSL-Las Vegas for further guidance.
3.4.2.2 Conductivity BalanceEstimate the specific conductance of a sample
by summing the equivalent conductances for each measured ion. Calcu-
late the equivalent conductance for each ion by multiplying the ion
concentration by the appropriate factor in Table 3.8. Calculate the
percent conductance difference (%CD) as follows:
calculated cond. - measured cond.
% Conductance Difference = x 100
measured conductance
The ZCD must not exceed the limits listed in Table 3.7. As with the
ZID calculation, an unacceptable value for %CD indicates either the
presence of unmeasured ions or an analytical error in the sample
analysis. For the surface waters sampled, the ions included in the
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TABLE 3.7. CHEMICAL REANALYSIS CRITERIA
A. Anion-Cation Balance
Maximum
Total Ion Strength (ueq/L) % Ion Differencea
<50 60
^50<100 30
_>100 15
B. Specific Conductance
Maximum
Measured Conductance (uS/cm) - % Conductance Difference5
<5 50
>5<30 30
>30 20
alf the absolute value of the percent difference exceeds these values,
the sample is reanalyzed. When reanalysis is indicated, the data for
each parameter are examined for possible analytical error. Any suspect
results are then redetertnined, and the above percent differences are
recalculated (Peden, 1981). If the differences are still unacceptable
or if no suspect data are identified, the QA manager should be contacted
for guidance.
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TABLE 3.8. CONDUCTANCE FACTORS OF IONS3
Ion
Specific
Conductance
(uS/cm at 25°C)
per mg/L
Ion
Specific
Conductance
at 25°C)
per mg/L
Ca2+
CT
co32-
H+
HC03-
Mg2+
2.60
2.14
2.82
3.5 x 105
(per mole/L)
0.715
3.82
[H+] moles/L = 10
pH = pH determine
Kw
[OH-] =
[H+]
5.080
Hffi ~ - n
ru+i
4.996
Na+ 2.13
NH4+ 4.13
S042' 1.54
N03" 1.15
K+ 1.84
OH" 1.92 x 105
(per mole/L)
-pH
d at V=0 of the BNC titration.
[DIC(mg/D] [H+] K1
2 + [H+] Kx + Kj K2
[DIC(mg/D] K:K2
ru"*"12 4. rH"*"~\v 4. \t v
Ln J ~ Ln Jl\i T |\i |^/j
1 it.
= 4.4463 x 10"7 K2 = 4.6881 x 10"11
aAPHA et al., 1985; Weast, 1972.
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%CD calculation are expected to account for 90 to 100 percent of the
ions in a sample. However, in contrast to the %ID calculation, there
is no term in the %CD calculation to account for protolytes not
specifically determined.
Examine the data from samples that do not meet the %CD criteria for
possible causes of the unacceptable %CD, such as improper data
reporting or analysis. The presence or absence of unmeasured pro-
tolytes can be tested by the procedures described in section 4. Note
that the absence of unmeasured protolytes is positive evidence that
the %CD exceeds the maximum difference because of analytical error.
Redetermine any parameter that is identified as suspect. If an
explanation for the poor %CD cannot be found and if the problem cannot
be corrected, contact the QA manager at EMSL-Las Vegas for further
guidance.
3.5 Data Reporting
. Record the results from each method on the data form indicated in Table
3.9 (blank data forms are included in Appendix B). Report results to the
number of decimal places in the actual detection limit. However, report
no more than four significant figures. Sample results from reanalyzed
samples (occasionally samples are reanalyzed for QC reasons) are annotated
by the letter R. Results obtained by standard additions are annotated by
the letter G. These and other data qualifiers are listed in Table 3.10.
After the forms are completed, the laboratory manager must sign them to
indicate that he has reviewed the data and that the samples were analyzed
exactly as described in this manual. All deviations from the manual
require the authorization of the QA manager prior to sample analysis.
3.6 References
American Public Health Association, American Water Works Association, and
Water Pollution Control Federation, 1985. Standard Methods for the
Examination of Water and Wastewater, 16th Ed. APHA, Washington, D.C.
Kramer, J. R., 1982. ANC and BNC. j£: R. A. Minear, L. H. Keith
(eds.), Water Analysis. Vol. 1. Inorganic Species, Part 1.
Academic Press, Orlando, Florida.
McQuaker, N. R., P. D. Kluckner, and D. K. Sandberg, 1983. Chemical
Analysis of Acid Precipitation: pH and BNC Determinations. Environ.
Sci. Technol., v. 17 n. 7, pp. 431-435.
Peden, M. E., 1981. Sampling, Analytical, and Quality Assurance Protocols
for the National Atmospheric Deposition Program. Paper presented at
October 1981 ASTM D-22 Symposium and Workshop on Sampling and
Analysis of Rain. ASTM, Philadelphia, Pennsylvania.
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TABLE 3.9. LIST OF DATA FORMS
Data Form Description
11 Summary of sample results
13 ANC and BNC results
14a QC data for ANC and BNC analysis
15a Specific conductance (measured and
calculated)
16a Anion-cation balance calculations
17 Ion chromatography resolution test form
18 QA (detection limits)
19 Sample holding times summary
20 Blank and QCCS results
21 Dilution factors
22 Duplicate results
aForm is not required but is recommended for internal lab use.
Copies of raw data must be submitted as requested by the QA manager. All
original raw data must be retained by the lab until notified otherwise.
Raw data include data system printouts, chromatograms, notebooks, QC
charts, standard preparation data, and all information pertinent to
sample analysis.
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TABLE 3.10. NATIONAL SURFACE WATER SURVEY DATA QUALIFIERS
Qualifier Indicates
F Result outside criteria with consent of QA manager
G A typical result; already reanalyzed and confirmed by the
laboratory manager
H Holding time exceeded criteria (Form 19 only)
J Result not available; insufficient sample volume shipped
K Result not available; entire aliquot not shipped
L Result not available; analytical interference
M Result not available; sample lost or destroyed by lab
N Not required
P Result outside criteria, but insufficient volume for
reanalysis
Q Result outside QA criteria
R Result from reanalysis
S Contamination suspected
T Leaking container
U Result not required by procedure
V Anion-cation balance outside criteria because of DOC
W % Difference UD) calculation (Form 14) outside criteria
because of high DOC.
Y Available for miscellaneous comments
Z Available for miscellaneous comments
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U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes. EPA-600/4-79-020. U.S. EPA,
Cincinnati, Ohio.
Weast, R. C. (ed.), 1972. CRC Handbook of Chemistry and Physics, 53rd Ed,
CRC Press, Cleveland, Ohio.
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4.0 DETERMINATION OF BASE-NEUTRALIZING CAPACITY, ACID-NEUTRALIZING CAPACITY,
AND pH
4.1 Scope and Application
This procedure is applicable to the determination of pH, ANC, and BNC in
weakly buffered natural waters of low ionic strength. The terms ANC and
BNC refer to the acid-neutralizing capacity (ANC) and base-neutralizing
capacity (BNC) of systems which are based on the carbonate ion system.
(The soluble reacting species are HoC03, HC03~, and C03Z~.) For calcula-
tion purposes, it is assumed that the streams in this survey are repre-
sented by a carbonate ion system; hence, the ANC and BNC definitions are
made in relation to the carbonate ion species (Kramer, 1982; Butler, 1982).
4.2 Summary of Method
Samples are titrated with standardized acid and base while monitoring and
recording the pH. The BNC and ANC are determined by analyzing the titra-
tion data by using a modified Gran analysis technique (Kramer, 1982; Butler,
1982; Kramer, 1984; Gran, 1952).
The Gran analysis technique defines the Gran functions F^ and ?2 based
upon the sample volume, the acid or base volume added, and the carbonate
dissociation constants. The Gran functions are calculated for several
data pairs of titrant volume added (either acid or base) and the resulting
pH. The data pairs are chosen so that they cross the ANC and BNC equiv-
alence points. When the Gran functions are plotted versus volume of
titrant added, the linear portion of each curve can be interpolated to the
equivalence point.
The pH is determined prior to the start of the titrations with the elec-
trode used during the titration. (U.S. EPA, 1983; McQuaker et al., 1983;
NBS, 1982).
The air-equilibrated pH is determined similarly after equilibrating the
sample with 300 ppm C0£ in air. Air equilibration is expected to nor-
malize pH values by factoring out the day-to-day and seasonal fluctuations
in dissolved C0£ concentrations.
4.3 Interferences
No interferences are known.
4.4 Safety
The standards, sample types, and most reagents pose little hazard to the
analyst. Protective clothing (lab coat and gloves) and safety glasses
must be used when handling concentrated acids and bases.
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Gas cylinders must be secured in an upright position.
4.5 Apparatus and Equipment
4.5.1 pH/mV Meter--A digital pH/mV meter capable of measuring pH to ±0.01 pH
unit, potential to ±1 mV, and temperature to ±0.5eC must be used. It
must also have automatic temperature compensation capability.
4.5.2 pH ElectrodesHigh-quality, low-sodium glass pH and reference elec-
trodes must be used. (Gel-type reference electrodes must not be used.)
A combination electrode is recommended (such as the Orion Ross combina-
tion pH electrode or equivalent), and the procedure is written assuming
one is used.
4.5.3 BuretA microburet capable of precisely and accurately delivering 10 to
50 piL must be used (relative error and standard deviation less than 1
percent).
4.5.4 Teflon Stir Bars
4.5.5 Variable Speed Magnetic Stirrer
4.5.6 Plastic Gas Dispersion Tube
NOTE: Glass dispersion tubes must not be used because they can add
ANC to a sample. Plastic dispersion tubes are available in most
fish-aquarium supply stores.
4.5.7 Titration SystemAlternatively to items 4.5.1 through 4.5.3, a commer-
cial titration instrument meeting the same specifications may be used.
4.6 Reagents and Consumable Materials
4.6.1 Carbon Dioxide Gas (300 ppm C02 in Air)Certified Standard Grade
4.6.2 Hydrochloric Acid Titrant (0.01N HCDAdd 0.8 ml concentrated hydro-
chloric acid (HC1, 12N, ACS reagent grade or equivalent) to 500 ml
water, then dilute to 1.00 L with water. Standardize as described in
section 4.8.1.
4.6.3 Nitrogen Gas (N2)C02-free
4.6.4 Potassium Chloride Solution (0.10 M KC1)Dissolve 7.5 g KC1 (Alfa
Ultrapure or equivalent) in water, then dilute to 1.00 L with water.
4.6.5 Potassium Hydrogen Phthalate (KHP)Dry 5 to 10 g KHP (ACS-certified
primary standard grade or equivalent) at 110°C for 2 hours, then store
in a desiccator.
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4.6.6 pH Calibration Buffers (pH 4, 7, and 10)NBS-traceable pH buffers at pH
values of 4, 7, and 10.
4.6.7 pH QC Samples (pH 4 and 10)--pH 4 QC sample - dilute 1.00 ml stand-
ardized 0.01N HC1 titrant to 100.00 ml with water. The theoretical pH
is calculated by:
i /NHC1\
pH = -log
\100 /
4.6.8 pH 10 QC sample - Dilute 1.00 ml of the standardized 0.01N NaOH
titrant to 100.00 ml with water. The theoretical pH is calculated by:
/NNaOH\
pH = 14 + log
\ 100
4.6.9 Sodium Carbonate (Na2C03)~Dry 5 to 10 g Na2C03 (ACS certified primary
standard grade or equivalent) at 110°C for 2 hours, then store in a
desiccator.
4.6.10 Sodium Hydroxide Stock Solution (50 percent w/v NaOH)--Dissolve 100 g
NaOH (ACS reagent grade or equivalent) in 100 ml water. After cooling
and allowing any precipitate to settle (may be hastened by centrifuga-
tion), transfer the supernatant to a polyethylene bottle. Store tightly
capped and avoid atmospheric exposure.
4.6.11 Sodium Hydroxide Titrant (0.01 N NaOH)--Dilute 0.6 to 0.7 mL 50 percent
NaOH to 1.0 L with water. Standardize as described in section 4.8.2.
4.6.12 WaterWater used to prepare reagents and standards must conform to ASTM
D 1193 specifications for Type I water (ASTM, 1984).
4.7 Sample Collection, Preservation, and Storage
The sample for which BNC, ANC, and pH is to be determined is delivered to
the lab in a 500-mL amber polyethylene bottle (aliquot 5). Store at 4°C
and minimize atmospheric exposure.
4.8 Calibration and Standardization
4.8.1 Standardization of HC1 Titrant
4.8.1.1 Weigh about 1 g anhydrous Na2C03 to the nearest 0.1 mg, dissolve in
water, then dilute to 1.000 L. Calculate the concentration by the
following equation.
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Wt. Na2C03 g 1
CO = --- " ' x
2 3 106.00 g 1 mole 1L
mole 2 eq
NOTE: This solution is to be freshly prepared just before use.
4.8.1.2 Calibrate the pH meter and electrode as recommended by the manu-
facturer.
4.8.1.3 Pipet 1.00 ml standard Na2C03 plus 40.00 ml COo-free deionized water
into a clean, dry titration vessel. Add a Teflon stir bar and stir
at a medium speed (no visible vortex).
4.8.1.4 Immerse the pH electrode and record the pH when a stable reading is
obtained.
4.8.1.5 Add a known volume of the HC1 titrant and record the pH when a
stable reading is obtained. Use the following table as a guide to
the volume of titrant that should be added in different pH ranges:
Maximum Volume Increment
pH of HC1 Titrant (ml)
>7.5 0.2
7.5-4 0.1
<4 0.2
Continue the titration until the pH <4. Obtain at least seven data
points in the range pH 4 to 7.
4.8.1.6 Calculate F^ for eacn data Pair (volume acid added, pH) with pH in
the range 4 to 7:
w
F1h = (V. + V) I = =-^ ) + - - [H+:
*-' *> / t* . » \ lrii+"iX.r*i4'ni* \» \» I r ij+T
Ln J
= (vs + v)
VP / r 11+ "! i/ , o v \/
ew / LnjNl*ti\li\o
si i i e.
(Vs + V) l[H*]2 + [H+]K1 +
I/ I/
Kl K2
= Gran function
Vs = Initial sample volume = 41.00 ml
V = Volume of HC1 added in ml
C = N Na2C03/(2 x dilution factor)
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[H"1"] = 10"pH
Kj = 4.4463 X 10~7
K2 = 4.6881 x 10~n
Kw = 1.01 x 10"14
4.8.1.7 Plot F^ versus V. Using the points on the linear portion of the
plot, perform a linear regression of F^ on V to obtain the coef-
ficients of the line:
Flb = a + bV
The correlation coefficient should exceed 0.999. If it does not,
reexamine the plot to make sure only points on the linear portion
are used in the linear regression.
4.8.1.8 Calculate the equivalence volume, Vj, by:
Y! = -a/b
then calculate the HC1 normality by:
N Na2C03 x V Na2C03
NHC1 =
4.8.1.9 Repeat the titration and calculation three times (steps 4.8.1.3
through 4.8.1.8). Calculate an average N^r/i a"d standard deviation.
The RSD must be less than 2 percent. If it is not, the entire
standardization must be repeated until it is less than 2 percent.
4.8.1.10 The concentration of every new batch of HC1 titrant must be cross
checked by using the procedure described in section 4.8.2.2.
4.8.1.11 Store in a clean polyethylene bottle. Although the HC1 titrant is
stable, it must be restandardized monthly (sections 4.8.1.1 through
4.8.1.9).
NOTE: An example of an HC1 standardization is given in Appendix
C-1.0.
4.8.2 Standardization of NaOH Titrant
Every batch of NaOH titrant is initially standardized against KHP
(section 4.8.2.1), and the standardization is cross-checked against
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standardized HC1 titrant (section 4.8.2.2). Thereafter, it is
restandardized daily against the HC1 titrant (section 4.8.2.3).
4.8.2.1 Initial NaOH standardization
Weigh about 0.2 g KHP to the nearest 0.1 mg, dissolve in water, then
dilute to 1.000 L. Calculate the normality of the solution by the
following equation.
wt. KHP g 1
204.22 g 1 L
eq
Calibrate the pH electrode and meter as recommended by the
manufacturer.
Purge the titration vessel with C02~free nitrogen, then pi pet 5.00
ml standard KHP solution and 20.00 ml C02~free water into the vessel.
Maintain a C02~free atmosphere above the sample throughout the
titration.
Add a Teflon stir bar and stir at a medium speed (no visible vortex).
Immerse the pH electrode and record the reading when it stabilizes.
Titrate with the 0.01N NaOH by using the increments specified in the
table below. Record the volume and pH (when stable) between addi-
tions. Continue the titration until the pH >10. Obtain at least
four data points in the pH range 5 to 7 and four data points in the
pH range 7 to 11.
Maximum Volume Increment of
pH NaOH Titrant (ml.)
<5 0.10
5 to 9 0.05
>9 0.2
Calculate F3& for each data pair (volume added, pH) with a pH 5 to
10.
VCC / [H+]Ki + 2 [H+]2 \ Kw
F3b = (Vs + V) S ' L !- r"+n
(Vs + V) \[H+]2 + [H+]K, + K! K9/ [H+]
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= Gran function
Vs = Initial sample volume = 25.00 ml
V = Volume of NaOH added (ml)
C = N KHP corrected for initial dilution = N KHP/5
[H+] = 10-PH
K! = 1.3 x 10~3
K2 = 3.9 x 10"6
Kw = 1.01 x 10"14
Plot P3b versus V. Using the points on the linear portion of the plot,
perform a linear regression of F3D on V to obtain the coefficients of
the line:
F3b = a + bV
The correlation coefficient should exceed 0.999. If it does not,
examine the plot to ensure that only points on the linear portion are
used in the linear regression.
Calculate the equivalence volume, 73, by:
V3 = -a/b
then calculate the NaOH normality by:
NKHP x VKHP
NNaOH =
Repeat the titration and calculation a total of three times.
Calculate an average N^on and standard deviation. The RSD must be
less than 2 percent. If not, the entire standardization must be
repeated until the RSD is less than 2 percent.
4.8.2.2 NaOH-HCl Standardization Cross-check
Purge a titration vessel with C02~free nitrogen, then pipet 0.500 ml
of 0.01N NaOH and 25.00 ml of COp-free water into the vessel.
Maintain a C02-free atmosphere above the sample.
Add a Teflon stir bar and stir at a medium speed.
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Immerse the pH electrode and record the reading when it stabilizes.
Titrate with the standardized 0.01N HC1 by using the increments
specified in the table below. Record the volume and pH (when stable)
between additions. Continue the titration until the pH is less than
3.5. Obtain at least seven data points in the pH range 4 to 10.
Maximum Volume Increment of
pH HC1 Titrant (ml)
>10 0.2
10 to 4 0.05
<4 0.2
Calculate Fj for each data pair (V, pH) with a pH 4 to 10.
. Kw
Fl = (vs + v)
FI = Gran function
Ys = Initial sample volume = 25.5 ml
V = Volume of HC1 added (ml)
Kw = 1.01 x 10'14
[H+] = 10-PH
Plot FI versus V. Using the points on the linear portion of the
plot, perform a linear regression of FI on V to obtain the coeffi-
cients of the line:
Fj = a + bV
The correlation coefficient should exceed 0.999. If not, reexamine
the plot to ensure that only points on the linear portion are used
in the linear regression.
Calculate the equivalence volume, Vj, by:
Vj = -a/b
then calculate the HC1 normality (designated as N'uri) by:
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NNaOH x vNaOH
VNaOH = 0-500
Calculate the absolute relative percent difference (RPD) between
and NHCI (normality determined in section 4.8.1) by:
RPD =
N*HC1 " NHC1
0.5
x 100
The absolute RPD must be less than 5 percent. If it is not, then a
problem exists in either the acid or the base standardization or both
(bad reagents, out-of-calibration burets, etc.). The problem must be
identified, and both procedures 4.8.1 and 4.8.2 repeated until the
RPD calculated above is less than 5 percent.
4.8.2.3 Daily NaOH Standardization
Calibrate the pH meter and electrode as recommended by the manu-
facturer.
Purge the titration vessel with COo-free nitrogen, then pipet 1.000
ml NaOH titrant plus 25.00 mL O^-free water into the vessel.
Maintain a C02~free nitrogen atmosphere above the sample. (Smaller
volumes of NaOH may be used. A known volume of C02-free water
should be added to bring solution to a convenient volume.)
Add a Teflon stir bar and stir at a medium speed.
Immerse the pH electrode and record the reading when it stabilizes.
Titrate with the standardized HC1 titrant by using the increments
specified in the table below. Record the volume and pH (when stable)
between additions. Continue the titration until the pH <4. Obtain
at least seven data points in the pH range 4 to 10.
PH
10 to 4
<4
Maximum Volume Increment of
HC1 Titrant (ml)
0.2
0.05
0.2
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Calculate Fj for each data pair (volume acid added, pH) with a pH
4 to 10:
F = (v + V) - [H+]
1 S
FI = Gran function
Vs = Initial sample volume = 26.00 ml
V = Volume of HC1 added
Kw = 1.01 x 10'14
[H*] = 10~PH
Plot F! versus V. Using the points on the linear portion of the
plot, perform a linear regression of Fj on V to obtain the coeffi-
cients of the line:
F! = a + bV
The correlation coefficient should exceed 0.999. If it does not,
reexamine the plot to make sure that only points on the linear
portion are used in the linear regression.
Calculate the equivalence volume, Vj, by:
Vx = -a/b
then calculate the NaOH normality by:
NHCI * vx
NNaOH
vNaOH
Repeat the titration and calculation twice more. Calculate an
average NNa0u and standard deviation. The RSD must be less than
2 percent. If it is not, the entire standardization must be repeated
until the RSD is less than 2 percent.
Because the NaOH titrant can readily deteriorate through exposure to
the air, every effort must be made to prevent its exposure to the air
at all times. Furthermore, it must be standardized daily or before
every major work shift. Store the NaOH titrant in a linear poly-
ethylene or Teflon container with a C02~free atmosphere, e.g.,
under C02~free air, nitrogen, or argon.
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NOTE: An example of NaOH standardization is given in Appendix C.
4.8.3 Calibration and Characterization of Electrodes
Separate electrodes must be used for the acid and base titrations. Each
new electrode pair must be rigorously evaluated for Nernstian response
by using the procedure described in section 4.8.3.1 prior to analyzing
samples. After the initial electrode evaluation, the electrodes are
calibrated daily by using the procedure in section 4.8.3.2.
4.8.3.1 Rigorous Calibration ProcedureThis procedure calibrates and evaluates
the Nernstian response of an electrode. Also, it familiarizes the
analyst with the characteristic response time of the electrode.
Following the instructions of the manufacturer, calibrate the electrode
and meter used for acid titrations with pH 7 and 4 buffer solutions
and calibrate the electrode used for base titrations with pH 7 and 10
buffer solutions.
Prepare a blank solution by pipetting 50.00 ml C02-free water and
0.50 ml 0.10M KC1 into a titration vessel.
Add a Teflon stir bar and stir at a medium speed by using a magnetic
stirrer.
Titrate the blank with standardized 0.01N HC1 by using the increments
specified in the table below. Continue the titration until the pH
is 3.3 to 3.5. Record the pH between each addition, noting the time
required for stabilization. Obtain at least seven data points that
have a pH less than 4.
Maximum Volume Increment of
pH HC1 Titrant (ml)
>4 0.050
<4 0.3
Prepare a fresh aliquot of water and 0.1M KC1 as in 4.8.3.1.2.
Under a C02~free atmosphere, titrate the blank with standardized
0.01N NaOH by using the increments specified in the table below.
Continue the titration until the pH is 10.5 to 11. Record the pH
between each addition. Obtain at least 10 data points between pH 9
and 10.5.
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Maximum Volume Increment of
pH NaOH Titrant (ml)
<10 0.10
>10 0.20
For each titration, calculate the pH for each data by point using
pH* = -log [H+]. [H+] is calculated by:
acid titration
base titration
[H+] =
VA = acid volume
CA = HC1 concentration in eq/L
Vs = sample volume = 50.5 mL
kw = 1.01 x 10'14
VB = base volume
CB = NaOH concentration in eq/L
For each titration, plot the measured pH versus the calculated pH
(designated as pH*). Perform a linear regression on each plot to
obtain the coefficients of the line:
pH = a + b(pH*)
The plots must be linear with b = 1.00 ± 0.05 and r > 0.999.
Typically, some nonlinearity exists in the pH region 6 to 8. This
is most likely because of small errors in titrant standardization,
impure salt solutions, or atmospheric CO? contamination. The non-
linear points should not be used in the linear regression.
If the plots are not linear and do not meet the specifications
above, the electrode should be considered suspect. The electrode
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characterization must then be repeated. If unacceptable results are
still obtained, the electrode must be replaced.
The plots for both titrations should be coincident. Combine the data
from both titrations and perform a linear least squares analysis on
the combined data to obtain new estimates for the coefficients of the
equation:
pH = a + b(pH*)
The electrodes are now calibrated. Do not move any controls on the
meter.
If the two plots are not coincident (i.e;, the coefficients a and b
do not overlap), the characterization must be repeated. If the plots
are still not coincident, the electrode must be replaced.
4.8.3.2 Daily Calibration ProcedureGenerally, the calibration curve
prepared above is stable from day to day. This daily calibration is
designed to verify the calibration on a day-to-day basis.
Copiously rinse the electrode with water. Immerse it in 20 ml of pH
7 buffer and stir for 1 to 2 minutes. Discard the buffer and replace
with an additional 40 ml of pH 7 buffer. While the solution is
gently stirred, measure the pH. Adjust the pH meter calibration knob
until the pH is equal to the theoretical pH of the buffer.
Record the theoretical pH and the final, measured pH reading. (The
two values should be identical).
Copiously rinse the electrode with water. Immerse it in 20 mL of pH
4 QC sample and stir for 1 to 2 minutes. Discard the sample and
replace it with an additional 40 ml pH 4 QC sample. While the solu-
tion is stirred, measure and record the pH. From the calibration
curve of pH versus pH*, determine the pH* for the observed pH.
Compare pH* to the theoretical pH of the QC sample. The two values
must agree within ±0.05 pH unit. If the two values do not agree, the
rigorous calibration procedure (section 4.8.3.1) must be performed
prior to sample analysis.
Repeat the above step with the pH 10 QC sample. This sample must be
kept under a COp-free atmosphere when in use, or acceptable results
may not be obtained.
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4.9 Quality Control
4.9.1 Duplicate Analysis
Analyze one sample per batch in duplicate. The duplicate precision
(expressed as an RSD) must be less than or equal to 10 percent. If the
duplicate precision is unacceptable (RSD >10 percent), then a problem
exists in the experimental technique. Determine and eliminate the cause
of the poor precision prior to continuing sample analysis.
4.9.2 Blank Analysis
Determine the ANC in one blank per batch. The absolute value of the ANC
must be less than or equal to 10 ueq/L. If it is not, contamination is
indicated. Determine and eliminate the contamination source (often the
source will be the water or KC1) prior to continuing sample analysis.
Blank values are calculated as described in 4.11.1 and Appendix C-4.0.
4.9.3 pH QCCS
Prior to analysis of the first sample in a shift and every five samples
thereafter, the appropriate pH QC sample (pH 4 QC for acid titrations
and pH 10 QC for base titrations) must be analyzed by using the following
procedure. Copiously rinse the electrode with deionized water. Immerse
it in 20 mL of QC sample and stir it for 30 to 60 seconds. Discard the
sample and replace it with an additional 40 ml of QC sample. While the
solution is gently stirred, measure and record the pH. From the
calibration curve of pH versus pH*, determine the pH*. If the pH* and
theoretical pH of the QC sample differ by more than ±0.05 pH unit, stop
the analysis and repeat the rigorous electrode calibration (section
4.8.3.1). Previously analyzed samples (up to last acceptable QC sample)
must be reanalyzed. Acceptable values of pH* are reported on Form 20.
4.9.4 Comparison of Initial Titration pH Values
The values for measured pH at Vt-jtrant = 0 (before KC1 spike) of the
acid and base titrations should be within ±0.1 pH unit. If they are
not, check operation to ensure that cross-contamination is not occurring.
4.9.5 For a sample with ANC <_ -15 ueq/L, calculate a value for ANC as follows:
[ANC]CQ = 106 x 10~PH* (pH at V = 0)
(The pH at Vtjtraqt = 0 is taken from the acid titration.) If ANC
differs from [ANCJco by more than ±10 ueq/L, then check the electrode
operation and calibration.
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4.9.6 Comparison of Calculated ANC and Measured ANC
A value for ANC can be calculated from the DIC concentration and the
pH of a sample. Two sets of pH and DIC values are obtained in the lab:
(1) pH* at V=0 of the base titration and the associated DIC concentration
and (2) pH of the air-equilibrated sample and the associated DIC concen-
tration. Each set can be used to calculate a value for ANC. The calcu-
lated values for Alk can then be compared to the measured value of ANC.
The comparison is useful in checking both the validity of assuming a
carbonate system and the possibility of analytical error. ANC is calcu-
lated from pH and DIC as follows:
[ANC]Q = calculated ANC from initial pH and DIC at time
of base titration
[ANC]c2 = calculated ANC from air-equilibrated pH and DIC
[ANC]C (ueq/L) =
DIC
12,011 UH+]2 +
rvw
+ - CH+]
K1K2
x 10C
DIC = DIC in mg/L (the factor 12,011 converts mg/L to
moles/L)
K! = 4.4463 x 10"7 at 25°C
K2 = 4.6881 x 10"11 at 25°C
Kw = 1.01 x 10~14 at 25°C
[ANC]ci and [ANC]c2 are compared as follows:
For [ANC]QI £100 ueq/L, the following condition applies:
[ANC]Ci - [ANC]C2
<15 ueq/L
For [ANCDci >100 ueq/L, the following condition applies:
[ANC]C1 - [ANC]C2
([ANC]C1 + [ANC]C2)/2
x 100
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If either of the above conditions is not satisfied, then the pH and DIG
values are suspect and must be remeasured. It is very important that
the pH and DIG be measured as closely together in time as possible. If
they are not measured closely in time, acceptable agreement between
[ANC]Q and [ANC]Q2 may not be obtained. When acceptable values for
[ANC]QJ and [ANC]r,2 are obtained, their average is compared to the
measured ANC as described below.
For [ANC]r_avg 5.100 ueq/L, then the difference "D" and the acceptance
window "w are:
D = [ANC]c.avg - ANC, and w = 15 ueq/L
For [ANC]c-avg >10° Meq/L, then:
- ANC
D = - - x 100, and w = 10%
[ANC]C-avg
If |D| w, then an analytical problem exists in the pH
determination, DIG determination, or acid titration (such as titrant
concentration). In this case the problem must be identified, and the
sample must be reanalyzed.
4.9.7 Comparison of Calculated BNC and Measured BNC
Just as for ANC, pH and DIG values can be used to calculate a BNC
value. Since the BNC of a sample changes with changing DIC, only the
initial pH and DIC values measured at the beginning of the base titra-
tion are used to calculate an BNC value. This calculated BNC is then
compared to the measured BNC value. BNC is calculated by:
[BNC]C (ueq/L) =
DIC / [H+]2 - K,K? \ Kw
_ I i £ \ + r^j+-i _ "
12,011 UH+]2 + [H^K! + KLK2 y [H+]
is compared to BNC as described below.
For [BNClc £100 peq/L, then:
D = [BNC]C - BNC, and w = 10 ueq/L
For [BNClc >100 peq/L, then:
x 10
,6
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[BNC]C - BNC
D = x 100, and w = 10%
[BNC]C
If |D| £w, then it is valid to assume a carbonate system. If D <-w,
the assumption of a pure carbonate system is not valid, and the sample
contains noncarbonate protolytes such as organic species.
If D >w, then an analytical problem exists in the pH determination,
DIG determination, or base titration (such as titrant concentration).
In this case the problem must be identified, and the sample must be
reanalyzed.
4.9.8 Comparison of Calculated Total Carbonate and Measured Total Carbonate
If the assumption of a carbonate system is valid, the sum of ANC plus
BNC is equal to the total carbonate. This assumption can be checked by
calculating the total carbonate from the DIC, then comparing the calcu-
lated total carbonate to the measured estimate of total carbonate (the
sum of ANC plus BNC). The total carbonate is calculated by:
GC (umole/L) = DIC (mg/L) x 83.26 (umole/mg)
CQ is compared to (ANC + BNC) as follows:
For CQ £100 umole/L, then:
D = GC - (ANC + BNC), and w = 10 umole/L
For Cc >100 umole/L, then:
Cc - (ANC + BNC)
D = x 100, and w = 10%
CC
If |D| £w, the assumption of a carbonate system is valid. If D <-w,
the assumption is not valid, and the sample contains noncarbonate
protolytes. If D >w, an analytical problem exists. It must be
identified, and the sample must be reanalyzed.
4.10 Procedure
An acid titration (section 4.10.1) and a base titration (section 4.10.2)
are necessary to determine the BNC and ANC of a sample. As part of each
titration, the sample pH is determined. The air-equilibrated pH is
determined in a separate sample portion (section 4.10.3).
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4.10.1 Acid Titration
4.10.1.1 Allow a sealed sample (aliquot 5) to reach ambient temperature.
4.10.1.2 Copiously rinse the electrode with deionized water, then immerse in
10 to 20 ml sample. Stir for 30 to 60 seconds.
4.10.1.3 Pipet 40.00 ml of sample into a clean, dry titration flask.
4.10.1.4 Add a clean Teflon stir bar and place on a magnetic stirrer. Stir
at a medium speed (no visible vortex).
4.10.1.5 Immerse the pH electrode and read pH. Record pH on Forms 11 and 13
when the reading stabilizes (1 to 2 minutes). This is the initial
measured pH at Vfjtrant = °-
4.10.1.6 Add 0.40 ml 0.1M KC1. Read and record the pH on Form 13. This is
the initial measured pH at V-fjtrant = 0 after addition of KC1 spike.
4.10.1.7 Add increments of 0.01N HC1 as specified in the table below. Record
the volume of HC1 added and the pH when a stable reading is obtained.
Adjust the volume increment of titrant so that readings can be taken
at pH values of 4.5 and 4.2. Continue the titration until the pH is
between 3.3 and 3.5. Obtain at least six data points that have a pH
less than 4.
PH
>9
9.0 to 7.0
7.0 to 5.5
5.5 to 4.5
4.5 to 3.75
<3.75
Maximum Volume Increment of
HC1 Titrant (mL)
0.1
0.025
0.1
0.05
0.1
0.3
4.10.2 Base Titration
4.10.2.1 Take a portion of aliquot 5 at this time for DIC determination. If
the DIC is not determined immediately, the sample must be kept sealed
from the atmosphere. A simple way to do this is to withdraw the
sample for DIC by using a syringe equipped with a syringe valve. By
closing the valve, the sample is sealed from the atmosphere (syringe
valves that fit standard Luer-Lok syringes are available from most
chromatography supply companies).
4.10.2.2 Purge the titration vessel with C02-free air, N2, or Ar.
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4.10.2.3 Copiously rinse the electrode with deionized water, then immerse in
10 to 20 ml sample for 30 to 60 seconds.
4.10.2.4 Pipet 40.00 ml sample into the C02-free titration vessel. Maintain
a C02-free atmosphere above the sample. Do not bubble the N2 (or
other C02-free gas) through the sample. Add a clean Teflon stir bar
to the vessel and place it on a magnetic stirrer. Do not turn
stirrer on at this point.
4.10.2.5 Immerse the pH electrode, read pH, and record pH on Forms 11 and 13
when pH stabilizes. This is the initial measured pH at Vfjtrant
= 0.
4.10.2.6 Add 0.40 ml 0.10M KC1. Stir for 10 to 15 seconds. Read pH, and
record pH on Form 13.
4.10.2.7 Add 0.025 mL of 0.01N NaOH and begin gentle stirring (no visible
vortex). Record the NaOH volume and pH when it stabilizes. Continue
the titration by adding increments of NaOH as specified below until
the pH >11. Record the volume of NaOH added and the pH after each
addition. Obtain at least 10 data points in the pH region 9 to 10.5.
If the initial sample pH is less than 7, obtain at least 5 data
points below pH 8.
Maximum Volume Increment of
pH NaOH Titrant (ml)
<5 0.025
5 to 7 0.050
7 to 9 0.025
9 to 10 0.10
10 to 10.5 0.30
>10.5 1.00
4.10.3 Air-Equilibrated pH Measurement
4.10.3.1 Allow the sealed sample (aliquot 5) to reach ambient temperature.
4.10.3.2 Copiously rinse the electrode with deionized water, then immerse
in 10 to 20 ml sample. Stir for 30 to 60 seconds.
4.10.3.3 Pipet 20 to 40 ml sample into a clean, dry titration flask.
4.10.3.4 Add a clean Teflon stir bar and place on a magnetic stirrer.
Stir at a medium speed.
4.10.3.5 Bubble standard gas containing 300 ppm C02 through the sample
for 20 minutes. Measure and record the pH.
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4.10.3.6 Take a subsample at this time for DIG determination. The subsample
must be kept sealed from the atmosphere prior to analysis. The DIG
should be measured as soon as possible.
4.11 Calculations
During the titrations, any substance which reacts with the acid or base
is titrated. However, for calculations, it is assumed that the samples
represent carbonate systems and that the only reacting species are H+,
OH~, H2C03, HCO^, and C032". When use is made of this assumption, the
two parameters
"ANC" and "C02-BNC" are calculated. The validity of the assumption is
checked as described in sections 4.9.6 through 4.9.8.
The theory behind the calculations is available elsewhere (Kramer, 1982;
Butler, 1982; Kramer, 1984). Examples of the calculations are given in
Appendix C.
4.11.1 Initial Calculations
4.11.1.1 From the calibration curve of measured pH versus calculated pH (pH*),
determine pH* for each pH value obtained during both the acid and
base titrations. Next, convert all pH* values to hydrogen ion
concentrations by using the equation:
[H+] = 10-PH*
4.11.1.2 Using the acid titration data, calculate the Gran function Fla for
each data pair (Va, pH*) in which pH* <4:
Fla = (vs + V ^
Vs = Total initial sample volume (40.00 + 0.400) ml
Va = Cumulative volume of acid titrant added
Plot Fia versus Va. The data should be on a straight line with
the equation:
Fla = a + bVa
Perform a linear regression of Fja on Va to determine the correlation
coefficient (r) and the coefficients a and b. The coefficient r
should exceed 0.999. If it does not, examine the data to ensure that
only data on the linear portion of the plot were used in the regres-
sion. If any outliers are detected, repeat the regression analysis.
Calculate an initial estimate of the equivalence volume (Vj) by:
V! = -a/b
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TABLE 4.1. LIST OF CALCULATION PROCEDURES FOR COMBINATIONS
OF INITIAL Vj AND pH*
Sampl
Initial Vj
<0
>0
>0
e Description
Initial pH*
-
£7.6
>7.6
Calculation
Procedure
A
B
C
Section No.
4.11.2
4.11.3
4.11.4
NOTE: For blank analyses, calculate ANC by ANC = Vj Ca/Vsa.
Further calculations are not necessary.
Further calculations are based on this initial estimate of Vj and the
initial sample pH*. Table 4.1 below lists the appropriate calcula-
tion procedure for the various combinations of Vj and initial sample
pH*.
4.11.1.3 Throughout the calculations, there are several equations and
constants that are frequently used. These are listed in Table 4.2.
4.11.2 Calculation Procedure A (Initial Yj <0)
4.11.2.1 From the base titration data, determine which data set (V, pH*)
has the pH* nearest (but not exceeding) a pH = 8.2. As an initial
estimate, set the equivalence volume V? equal to the volume of this
data set. Next, calculate initial estimates of ANC, BNC, and C by:
ANC =
Vsa
Ca = concentration of acid titrant
Vsa = original sample volume (acid titration)
V2Cb
BNC = -
Vsb
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TABLE 4.2. LIST OF FREQUENTLY USED EQUATIONS AND CONSTANTS
No.
Equation
1 Flc = (Vs + V)
" CtCH*]!^ + 2 KjKg) Kw
r H^* ~\ * 4- r H^" n K 4* n n r H*^* i
2c
= (V
V)
C([H+:i2 -
[H+]2 + [H*]Kj
Constants
and
variable
Vs
V
C
[H+]
Kl
K2
Kw
=
Total initial sample volume
Cumulative volume of titrant
Total carbonate expressed in
Hydrogen ion concentration
4.4463 x 10"7 at 25 Q
4.6881 x 10"n at 25 C
1.01 x 10"14 at 25 C
added
moles/L
Cfo = concentration of base titrant
vsb = original sample volume (base titration)
C = total carbonate = ANC + BNC
4.11.2.2 Calculate the Gran function Fic for the first 7 to 8 points of the
base titration by using equation 1, Table 4.2. Plot Fic versus Vf,.
Perform a linear regression with the points lying on trie linear
portion of the plot. Determine the coefficients of the line Fjc =
a + bV. The coefficient r should exceed 0.999. If it does not,
examine the plot to ensure that only points on the linear portion
are used. From the coefficients, calculate a new estimate of Vj by:
Y! = -a/b
Next, calculate the Gran function F2c (equation 2, Table 4.2) for
data from the base titration across the current estimate of V2. (Use
the first 4 to 6 sets with a volume less than V2 and the first 6 to 8
sets with a volume greater than V2.) Plot F2c versus V^. The data
should lie on a straight line with the equation F2c = a + bV. Per-
form a linear regression of F2c on V^ and determine the coefficients
of the line. If r <0.999 reexamine the data to ensure that only
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points on the linear portion were used in the regression. Calculate
a new estimate of V2 by:
V2 = -a/b
4.11.2.3 Calculate new estimates of ANC, BNC, and C by using the new estimates
of Vi and V2 (an asterisk indicates a new value).
v2cb
ANC* = - ; BNC* = - ; C* = ANC + BNC
Vsb
4.11.2.4 Compare the latest two values for total carbonate. If
>0.001
then calculate a new estimate for C by:
C(new) = (C + C*)/2
Using the new value for C, repeat the calculations in 4.11.2.2
through 4.11.2.4. Continue repeating the calculations until the
relative difference between C and C* is less than 0.001.
When the expression is less than 0.001, convert the final values for
ANC, BNC, and C to ueq/L by:
ANC (peq/L) = ANC (eq/L) x
BNC (ueq/L) = BNC (eq/L) x
C (ueq/L) = C (eq/L) x
4.11.3 Calculation Procedure B (Initial Vi >0, Initial pH* £7.6)
4.11.3.1 From the base titration data, determine which data set (V, pH*) has
the pH* nearest but not exceeding 8.2. As an initial estimate,
set the equivalence volume V2 equal to the volume of this data set.
Next calculate initial estimates of ANC, BNC, and C by:
V2Cb
ANC = - ; BNC = - ; C = ANC + BNC
sa Vsb
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4.11.3.2
4.11.3.3
4.11.3.4
Calculate the Gran function Flc (equation 1) for data sets from the
acid titration with volumes across the current estimate of V^ (use
the first 4 to 6 sets with volumes less than V^ and the first 6 to 8
sets with volumes greater than Vj). Plot Flc versus Va. The data
should lie on a line with the equation Fjr = a + bV. Perform a
linear regression of Fjc on Va and determine the coefficients of the
line. If r does not exceed 0.999, reexamine the data to ensure that
no outliers were used in the regression. Calculate a new estimate
for YI by:
Vj = -a/b
Next, calculate the Gran function ?2c (equation 2) for data sets
from the base titration with volumes across the current estimate of
V?. (Use the first 4 to 6 sets with volumes less than V2 and the
first 6 to 8 sets with volumes greater than V2). Plot F2c ver$us
V(j. The data should lie on a line with the equation F2C = a + bV.
Perform a linear regression of F2c on vb and determine the coeffi-
cients of the line. If r does not exceed 0.999, reexamine the data
to ensure that only data on the linear portion were included in the
regression. Calculate a new estimate for Y2 by:
V2 = -a/b
Calculate new estimates of ANC, BNC, and C using the latest
estimates of Vj and V2.
ANC* =
BNC* =
C* = ANC + BNC
sa
>0.001
Compare the latest two values for total carbonate. If:
C - C*
C + C*
then calculate a new estimate of C by:
C(new) = (C + C*)/2
Using the new value of C, repeat the calculations in 4.11.3.2
through 4.11.3.4. Continue repeating the calculations until the
above expression is less than 0.001.
When the expression is less than 0.001, convert the final values for
ANC, BNC, and C to ueq/L by:
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Section 4.0
Revision 2
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Page 25 of 27
ANC (Meq/L) = ANC (eq/L) x 106
BNC (Meq/L) = BNC (eq/L) x 106
C (ueq/L) = C (eq/L) x 106
4.11.4 Calculation Procedure C (Initial Vj >0, Initial pH* >7.6)
4.11.4.1 Obtain an initial estimate of the equivalence volume Y2 by following
the procedure in 4.11.4.1.1 if the initial sample pH* >8.2. If the
initial sample pH* <8.2, then follow the procedure in "4".11.4.1.2.
From the acid titration data, determine which data set (V, pH*) has
the pH* nearest but not exceeding 8.2. As an initial estimate, set
the equivalence volume V2 equal to the volume of this data set. Go
to section 4.11.4.1.3.
Using data sets from the acid titration with pH* values across a
pH = 7 (use 4 to 6 sets with a pH* <7 and 4 to 6 sets with a pH* >7),
calculate the Gran function F2a by:
F2a = (Vj - Va) [H+]
Plot F2a versus Va. The data should lie on a straight line with the
equation F2a = a + bV. Perform a linear regression of F2a on Va.
The coefficient r should exceed 0.999. If it does not, reexamine the
plot to ensure that only data on the linear portion were used in the
calculation. Calculate a new estimate for V2 by:
V2 = -a/b
Calculate estimates of ANC, BNC, and C by:
vlca 'V2ca
ANC = ; BNC = ; C = ANC + BNC
Vsa Vsa
4.11.4.2 Calculate the Gran function Flc (equation 1) for data sets from the
acid titration with volumes across the current estimate of Vj (use
the first 4 to 6 sets with volumes less than Vj and the first 6 to 8
sets with volumes greater than Vi). Plot Fig versus Va. The data
should lie on a straight line with the equation Fjc = a + bVa. Per-
form a linear regression of Flc on Va and determine the coefficients
of the line. The coefficient r should exceed 0.999. If it does not,
reexamine the plot to ensure that only data on the linear portion
were included in the regression. Calculate a new estimate for Vj by:
Vj = -a/b
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Section 4.0
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Page 26 of 27
Next, calculate the Gran function F2c (equation 2) for data sets
from the acid titration with volumes across the current estimate of
V2 (use the first 4 to 6 sets with volumes less than V2 and the
first 6 to 8 sets with volumes greater than V2). Plot F2c versus
Va. The data should lie on a straight line with the equation F2c
= a + bV. Perform a linear regression of F2c on Va and determine
the coefficients of the line. The coefficient r should exceed
0.999. If it does not, reexamine the plot to ensure that only data
on the linear portion were included in the regression. Calculate a
new estimate of V2 by:
V2 = -a/b
4.11.4.3 Calculate new estimates of ANC, BNC, and C by using the latest
estimates of Vj and V2.
ANC* = ; BNC* = ~ ; C* = ANC + BNC
vsa vsa
4.11.4.4 Compare the latest two values for total carbonate. If:
>0.001
then calculate a new estimate of C by:
C{new) = (C + C*)/2
Using this new value of C, repeat the calculations in 4.11.4.2
through 4.11.4.4. Continue repeating the calculations until the
above expression is less than 0.001.
When the expression is less than 0.001, convert the final values for
ANC, BNC, and C to ueq/L by:
ANC (ueq/L) = ANC (eq/L) x
BNC (ueq/L) = BNC (eq/L) x 106
C (ueq/L) = C (eq/L) x 106
4.12 References
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
-------
Section 4.0
Revision 2
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Page 27 of 27
Butler, J. N., 1982. Carbon Dioxide Equilibria and Their Applications.
Addison-Wesley Publications, Reading, Massachusetts.
Gran, G., 1952. Determination of the Equivalence Point in Potentio-
metric Titrations. Part II. Analyst, v. 77, pp. 661-671.
Kramer, J. R., 1982. ANC and BNC. Ir±: R. A. Minear and L. H. Keith
(eds.), Water Analysis, Vol. 1. Inorganic Species, Part 1.
Academic Press, Orlando, Florida.
Kramer, J. R., 1984. Modified Gran Analysis for Acid and Base Titra-
tions. Environmental Geochemistry Report No. 1984-2. McMaster
University, Hamilton, Ontario, Canada.
McQuaker, N. R., P. D. Kluckner, and D. K. Sandberg, 1983. Chemical
Analysis of Acid Precipitation: pH and BNC Determinations.
Environ. Sci. Technol., v. 17, n. 7, pp. 431-435.
National Bureau of Standards, 1982. Simulated Precipitation Reference
Materials, IV. NBSIR 82-2581. U.S. Department of Commerce - NBS,
Washington, D.C.
U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes, Method 150.1, pH. EPA-600/
4-79-020. U.S. EPA, Cincinnati, Ohio.
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Section 5.0
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Page 1 of 7
5.0 DETERMINATION OF AMMONIUM
5.1 Scope and Application
This method covers the determination of ammonia in natural surface waters
in the range of 0.01 to 2.6 mg/L NH^+. This range is for photometric
measurements made at 630 to 660 nm in a 15-mm or 50-mrn tubular flow cell.
Higher concentrations can be determined by sample dilution. Approximately
20 to 60 samples per hour can be analyzed.
5.2 Summary of Method
Alkaline phenol and hypochlorite react with ammonia to form an amount
of indophenol blue that is proportional to the ammonium concentration.
The blue color formed is intensified with sodium nitroprusside (U.S.
EPA, 1983).
5.3 Interferences
Calcium and magnesium ions may be present in concentration sufficient to
cause precipitation problems during analysis. A 5 percent EDTA solution
is used to prevent the precipitation of calcium and magnesium ions.
Sample turbidity may interfere with this method. Turbidity is removed
by filtration at the field station. Sample color that absorbs in the
photometric range used also interferes.
5.4 Safety
The calibration standards, sample types, and most reagents used in this
method pose no hazard to the analyst. Use protective clothing (lab coat
and gloves) and safety glasses when preparing reagents.
5.5 Apparatus and Equipment
5.5.1 Technicon AutoAnalyzer Unit (AAI or AAII) consisting of:
5,5.1.1 Sampler.
5.5.1.2 Manifold (AAI) or Analytical Cartridge (AAII).
5.5.1.3 Proportioning pump.
5.5.1.4 Heating bath with double-delay coil (AAI).
5.5.1.5 Colorimeter equipped with 15-mm tubular flow cell and 630- to 660-nm
filters.
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Section 5.0
Revision 2
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Page 2 of 7
5.5.1.6 Recorder.
5.5.1.7 Digital printer for AAII (optional).
5.6 Reagents and Consumable Materials
5.6.1 Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984).
5.6.2 Sulfuric Acid (5N) - Air Scrubber Solution
Carefully add 139 ml concentrated sulfuric acid to approximately 500 ml
ammonia-free water. Cool to room temperature and dilute to 1 L with
water.
5.6.3 Sodium Phenol ate Solution
Using a 1-L Erlenmeyer flask, dissolve 83 g phenol in 500 mL water. In
small increments, cautiously add with agitation 32 g NaOH. Periodically
cool flask under flowing tap water. When cool, dilute to 1 L with water.
5.6.4 Sodium Hypochlorite Solution
Dilute 150 ml of a bleach solution containing 5.25 percent NaOCl (such
as "Clorox") to 500 ml with water. Available chlorine level should
approximate 2 to 3 percent. Clorox is a proprietary product, and its
formulation is subject to change. The analyst must remain alert to
detecting any variation in this product significant to its use in this
procedure. Because of the instability of this product, storage over an
extended period should be avoided.
5.6.5 Disodium Ethylenediamine-Tetraacetate (EDTA) (5 percent w/v)
Dissolve 50 g EDTA (disodium salt) and approximately six pellets NaOH in
1 L water.
5.6.6 Sodium Nitroprusside (0.05 percent w/v)
Dissolve 0.5 g sodium nitroprusside in 1 L deionized water.
5.6.7 NH4+ Stock Standard Solution (1,000 mg/L)
Dissolve 2.9654 g anhydrous ammonium chloride, NfyCl (dried at 105°C for
2 hours), in water, and dilute to 1,000 ml.
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Section 5.0
Revision 2
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Page 3 of 7
5.6.8 Standard Solution A (10.00 mg/L NH4+)
Dilute 10.0 ml NH4+ stock standard solution to 1,000 ml with water.
5.6.9 Standard Solution B (1.000 mg/L NH4+)
Dilute 10.0 ml standard solution A to 100.0 ml with water.
5.6.10 Using standard solutions A and B, prepare (fresh daily) the following
standards in 100-mL volumetric flasks:
NH^ (mg/L) mL Standard Solution/100 mL
Solution B
0.01 1.0
0.02 2.0
0.05 5.0
0.10 10.0
Solution A
0.20 2.0
0.50 5.0
0.80 8.0
1.00 10.0
1.50 15.0
2.00 20.0
5.7 Sample Collection, Preservation, and Storage
Samples are collected, filtered, and preserved (addition of ^$04 until
pH <2) in the field. The samples must be stored at 4°C when not in use.
5.8 Calibration and Standardization
Analyze the series of ammonium standards as described in section 5.10.
Prepare a calibration curve by plotting the peak height versus standard
concentration.
5.9 Quality Control
The required QC is described in section 3.4.
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Section 5.0
Revision 2
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Page 4 of 7
5.10 Procedure
5.10.1 Since the intensity of the color used to quantify the concentration is
pH-dependent, the acid concentration of the wash water and the standard
ammonium solutions should approximate that of the samples. For example,
if the samples have been preserved with 2 mL concentrated H2S04/L, the
wash water and standards should also contain 2 ml concentrated H2S04/L.
5.10.2 For a working range of 0.01 to 2.6 mg/L NH4+ (AAI), set up the manifold
as shown in Figure 5.1. For a working range of 0.01 to 1.3 mg/L NH4+
(AAII), set up the manifold as shown in Figure 5.2. Higher concentra-
tions may be accommodated by sample dilution.
5.10.3 Allow both colorimeter and recorder to warm up for 30 minutes. Obtain a
stable baseline with all reagents by feeding distilled water through
sample line.
5.10.4 For the AAI system, sample at a rate of 20/hr, 1:1. For the AAII use a
60/hr 6:1 cam with a common wash.
5.10.5 Load sampler tray with unknown samples.
5.10.6 Switch sample line from water to sampler and begin analysis.
5.10.7 Dilute and reanalyze samples with an ammonia concentration exceeding the
calibrated concentration range.
5.11 Calculations
Compute concentration of samples by comparing sample peak heights with
calibration curve. Report results in mg/L NH4 .
5.12 Precision and Accuracy
In a single laboratory (EMSL-Cincinnati), when use was made of surface-
water samples at concentrations of 1.41, 0.77, 0.59, and 0.43 mg NH3-N/L,
the standard deviation was ±0.005 (U.S. EPA, 1983).
In a single laboratory (EMSL-Cincinnati), when use was made of surface-
water samples at concentrations of 0.16 and 1.44 mg NH3-N/L, recoveries
were 107 percent and 99 percent, respectively (U.S. EPA, 1983). These
recoveries are statistically significantly different from 100 percent.
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Section 5.0
Revision 2
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Page 5 of 7
5.13 References
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
U.S. Environmental Protection Agency, 1983 (revised). Methods for Chemical
Analysis of Water and Wastes, Method 350.1, Ammonia Nitrogen. EPA-
600/4-79-020. U.S. EPA, Cincinnati, Ohio.
-------
PROPORTIONING
SM» SMALL MIXING CO
LM* LARGE MIXING C
i
HEATING f
BATH37»CV
1
WASI
TOS
IL
OIL
LM
00000000
t
LM
00000000
SM OOOO 1
) r
t
1
H WATER
AMPLER
SM
OOOO
(WASTE
r1
\ 1
PUMP
P B
G G
R R
G G
W W
W W
R R
P P
ml/mln
2.9 WASH
2.0 SAMPLE c
)
SAMPLER
O.8 EOTA 2O/ hr.
2.O AIR*
O.6 PHENOLATE
0.6 HYPOCHLORITE
0.6 NITROPRUSSJOE
?«?
| WASTE
RECORDER
COLORIMETER 5N"H~6Cr
15 mm FLOW CELL 2 4
650- 660 nm FILTER
Figure 5.1. Ammonia manifold AAI.
-o o -ya co
to c+ < o
n> (T) ' r+
o> ~J* o
0 3
013
-hi 01
. ro
->J 00 O
-------
WASH WATER
TO SAMPLER
oono
HEATING
BATH
50* C
\
W*3 1 b
-<
^ \
»l IHI 1
j
J
RECORDER
*.
1
PROPORTIONING
PUMP
i
G G
0
O
R
0
W
0
R
0
BLACK
0
0
BLUE
o
DIGITAL
PRINTER
nl/mln.
2.0 WASH
O.23 AIR*
0.42 SAMPLE
0.6 EDTA
0.42 PHENOLATE
SAMPLER
60/hr.
61
0
_J
032 HYPOCHLORITE
0.42 NITROPRUSSIDE
.»
e/»Diionm TMQ
niifsu
COLORIMETER
SO mm FLOW CELL
650-660 nm FILTER
5N H2S04
Figure 5.2. Ammonia Manifold AAII.
"o o 30 oo
&> &> n> n>
fl> n> - r+
.. M _«.
^J ->. o
O =J
O I-1 3
-hi' in
. ro
~J OO O
CT>
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Section 6.0
Revision 2
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Page 1 of 6
6.0 DETERMINATION OF CHLORIDE, NITRATE, AND SULFATE BY ION CHROMATOGRAPHY
6.1 Scope and Application
This method is applicable to the determination of chloride, nitrate, and
sulfate in natural surface waters by ion chromatography (1C).
This method is restricted to use by or under the supervision of analysts
experienced in the use of ion chromatography and in the interpretation of
the resulting ion chromatogram.
6.2 Summary of Method
Samples are analyzed by 1C. 1C is a liquid chromatographic technique
that combines ion exchange chromatography, eluent suppression, and
conductimetric detection.
A filtered sample portion is injected into an ion chromatograph. The
sample is pumped through a precolumn, separator column, suppressor
column, and a conductivity detector. The precolumn and separator
column are packed with a low-capacity anion exchange resin. The sample
anions are separated in these two columns with the separation being
based on their affinity for the resin exchange sites.
The suppressor column reduces the conductivity of the eluent to a low
level and converts the sample anions to their acid form. Typical
reactions in the suppressor column are:
Na+ HC03" + R - H > HoC03 + R - Na
(high-conductivity eluant) (Tow conductivity)
Na+ A" + R - H > HA + R - Na
Three types of suppressor columns are available: the packed-bed
suppressor, the fiber suppressor, and the micromembrane suppressor. The
packed-bed suppressor contains a high-capacity cation exchange resin in
the hydrogen form. It is consumed during analysis and must be periodi-
cally regenerated off-line. The latter two suppressors are based on
cation exchange membranes. These suppressors are continuously regene-
rated throughout the analysis. Also, their dead volume is substantially
less than that of a packed-bed suppressor. For these two reasons, the
latter two suppressors are prefered.
The separated anions in their acid form are measured by using a conduc-
tivity cell. Anion identification is based on retention time. Quanti-
fication is performed by comparing sample peak heights to a calibration
curve generated from known standards (ASTM, 1984a; O'Dell et al., 1984;
Topol and Ozdemir, 1981).
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Section 6.0
Revision 2
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Page 2 of 6
6.3 Interferences
Interferences can be caused by substances with retention times that are
similar to and overlap those of the anion of interest. The stream samples
are not expected to contain any interfering species. Large amounts of an
anion can interfere with the peak resolution of an adjacent anion. Sample
dilution or spiking can be used to solve most interference problems.
The water dip or negative peak that elutes near and can interfere with
the chloride peak can be eliminated by the addition of the concentrated
eluant so that the eluant and sample matrix are similar.
Method interferences may be caused by contaminants in the reagent water,
reagents, glassware, and other sample processing apparatus that lead to
discrete artifacts or elevated baselines in ion chromatograms.
Samples that contain particles larger than 0.45 microns and reagent
solutions that contain particles larger than 0.20 microns require
filtration to prevent damage to instrument columns and flow systems.
6.4 Safety
Normal, accepted laboratory safety practices should be followed during
reagent preparation and instrument operation. The calibration standards,
samples, and most reagents pose no hazard to the analyst. Protective
clothing and safety glasses should be worn when handling concentrated
sulfuric acid.
6.5 Apparatus and Equipment
6.5.1 Ion Chromatograph
Analytical system complete with ion chromatograph and all accessories
(conductivity detector, autosampler, data recording system, etc.).
6.5.2 Anion Pre- and Separator Columns
Dionex Series AG-4A and AS-4A are recommended for use with the 2000i ion
chromatographs. AG-3 and AS-3 columns are recommended for older ion
chromatographs.
6.5.3 Suppressor Column
Dionex AFS fiber suppressor or AMMS membrane suppressor is recommended.
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Section 6.0
Revision 2
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Page 3 of 6
6.6 Reagents and Consumable Materials
Unless stated otherwise, all chemicals must be ACS reagent grade or
better. Also, salts used in preparation of standards must be dried at
105°C for 2 hours and stored in a desiccator.
6.6.1 Deionized Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984b).
6.6.2 Eluant Solution (0.0028M NaHC03/0.0020M Na2C03)
Dissolve 0.94 g sodium bicarbonate (NaHC03) and 0.85 g sodium car-
bonate (Na2C03) in water and dilute to 4 L. This eluant strength may be
adjusted for different columns according to the recommendations provided
by the manufacturer.
6.6.3 Fiber Suppressor Regenerant (0.025N ^04)
Add 2.8 ml concentrated sulfuric acid (^$04, Baker Ultrex grade or
equivalent) to 4 L water.
6.6.4 Stock Standard Solutions
6.6.4.1 Sulfate Stock Standard Solution (1,000 mg/L S042")Dissolve 1.8141 g
potassium sulfate (K2S04) in water and dilute to 1.000 L.
6.6.4.2 Chloride Stock Standard Solution (200 mg/L Cl~)--Dissolve 0.3297 g
sodium chloride (Nad) in water and dilute to 1.000 L.
6.6.4.3 Nitrate Stock Standard Solution (200 mg/L N03~)Dissolve 0.3261 g
potassium nitrate (KN03) in water and dilute to 1.000 L.
6.6.4.4 Fluoride Stock Standard Solution (1,000 mg/L F~)--Dissolve 2.2100 g
sodium fluoride (NaF) in water and dilute to 1.000 L.
6.6.4.5 Phosphate Stock Standard Solution (1,000 mg/L P)~Dissolve 4.3937 g
potassium phosphate (KH2P04) in water and dilute to 1.000 L.
6.6.4.6 Bromide Stock Standard Solution (1,000 mg/L Br~)Dissolve 1.2877 g
sodium bromide (NaBr) in water and dilute to 1.000 L.
6.6.4.7 Store stock standards in clean polyethylene bottles (cleaned without
acid by using procedure in Appendix A) at 4°C. Prepare monthly.
6.6.5 Mixed Resolution Sample (1 mg/L F~, 2 mg/L Cl~, 2 mg/L N03~, 2 mg/L
P, 2 mg/L Br", 5 mg/L SO/")
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Section 6.0
Revision 2
Date: 11/86
Page 4 of 6
Prepare by appropriate mixing and dilution of the stock standard
solutions.
6.7 Sample Collection, Preservation, and Storage
Samples are collected and filtered in the MPL. Store samples at 4°C when
not in use.
6.8 Calibration and Standardization
Each day (or work shift) for each analyte, analyze a blank and a series
of standards which bracket the expected analyte concentration range as
described in section 6.10. Prepare the standards daily by quantitative
dilution of the stock standard solutions. Suggested concentrations for
the dilute standards are given in Table 6.1.
TABLE 6.1. SUGGESTED CONCENTRATION OF DILUTE CALIBRATION STANDARDS
Concentration (mg/L)
Standard CV
1
2
3
4
5
6
0
0.020
0.10
0.50
1.00
3.00
0
0.020
0.10
0.50
1.00
3.00
0
0.20
0.50
2.00
5.00
10.00
Prepare a calibration curve for each analyte by plotting peak height
versus standard concentration.
6.9 Quality Control
General QC procedures are described in section 3.4.
6.9.1 Resolution Test
After calibration, analyze the mixed standard containing fluoride,
chloride, nitrate, phosphate, bromide, and sulfate. Resolution between
adjacent peaks must equal or exceed 60 percent. If not, replace or
clean the separator column and repeat calibration.
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Section 6.0
Revision 2
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Page 5 of 6
6.10 Procedure
6.10.1 Set up the 1C for operation. Typical operating conditions for a Dionex
2010i 1C are given in Table 6.2. Other conditions may be used depending
upon the columns and system selected.
TABLE 6.2. TYPICAL 1C OPERATING CONDITIONS
==============================================================================
1C: Dionex 2010i Sample Loop Size: 250 uL
Precolumn: AG-4A
Separator Column: AS-4A
Suppressor Column: AMMS
Eluant: 0.75mM NaHC03/2.0mM Na2C03
Eluant Flow Rate: 2.0 mL/min
Regenerant: 0.025N H2S04
Regenerant Flow Rate: 3 mL/min
Ion Typical Retention Time (min)
cr 1.8
N03~ 4.9
S02~ 8.1
6.10.2 Adjust detector range to cover the concentration range of samples.
6.10.3 Load injection loop (manually or via an autosampler) with the sample
(or standard) to be analyzed. Load five to ten times the volume
required to thoroughly flush the sample loop. Inject the sample.
Measure and record (manually or with a data system) the peak heights for
each analyte.
6.10.4 Dilute and reanalyze samples with an analyte concentration exceeding the
calibrated concentration range.
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Section 6.0
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Page 6 of 6
6.11 Calculations
Compute the sample concentration by comparing the sample peak height with
the calibration curve.
Report results in mg/L.
6.12 Precision and Accuracy
Typical single operator results for surface water analyses are listed in
Table 6.3 (O'Dell et al.. 1984).
TABLE 6.3. SINGLE-OPERATOR ACCURACY AND PRECISION (O'Dell et al . , 1984)a
Ion
CI-
NQ;
so?"
Spike
(mg/L)
1.0
0.5
10.0
Number of
Replicates
7
7
7
Mean %
Recovery
105
100
112
Standard
Deviation (mg/L)
0.14
0.0058
0.71
aThe conditions used by O'Dell were slightly different than those listed in
Table 6.2. However, the results are typical of what is expected.
6.13 References
American Society for Testing and Materials, 1984a. Annual Book of ASTM
Standards, Vol. 11.01, Standard Test Method for Anions in Water by
Ion Chroma tography, D4327-84. ASTM, Philadelphia, Pennsylvania.
American Society for Testing and Materials, 1984b. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
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
Chroma tography. EPA-600/4-85-017. U.S. Environmental Protection
Agency, Cincinnati, Ohio.
Topol, L. E., and S. Ozdemir, 1981. Quality Assurance Handbook for Air
Pollution Measurement Systems: Vol. V. Manual for Precipitation
Measurement Systems, Part II. Operations and Maintenance Manual.
EPA-600/4-82-042b. U.S. Environmental Protection Agency, Research
Triangle Park, North Carolina.
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Section 7.0
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Page 1 of 8
7.0 DETERMINATION OF DISSOLVED ORGANIC CARBON AND DISSOLVED INORGANIC CARBON
7.1 Scope and Application
This method is applicable to the determination of DIC and DOC in natural
surface waters.
This method is applicable over the concentration range 0.1 to 30 mg/L DIC
or DOC. The method detection limit is about 0.8 mg/L DOC and 0.1 mg/L
DIC, as determined from replicate analyses of a blank sample.
The method is written with the assumption that a Dohrman-Xertex DC-80
Analyzer is used. However, any instrumentation having similar operating
characteristics may also be used.
7.2 Summary of Method
Two samples, aliquots 4 and 5, are sent to the lab for analysis. Aliquot
4 is filtered and preserved in the field (acidified to pH <2 with
It is analyzed for DOC. Aliquot 5 is an unfiltered sample. It is
filtered and analyzed for DIC.
DOC is determined (after external sparging to remove DIC) by ultraviolet-
promoted persulfate oxidation which is followed by IR detection. DIC is
determined directly by acidifying to generate C02 which is followed by IR
detection (U.S. EPA, 1983; Xertex-Dohrman, 1984).
7.3 Interferences
No interferences are known.
7.4 Safety
The sample types, standards, and most reagents pose no hazard to the
analyst. Protective clothing (lab coat) and safety glasses should be worn
when preparing reagents and operating the instrument.
7.5 Apparatus and Equipment
7.5.1 Disposable plastic Luer-Lok syringes (for DIC samples) equipped with
Luer-Lok syringe valves.
7.5.2 Carbon Analyzer
This method is based on the Dohrman DC-80 Carbon Analyzer equipped with
a high-sensitivity sampler. The essential components of the instrument
are a sample injection valve, UV-reaction chamber, IR detector, and
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integrator. The injection valve should have a 5- to 7-mL sample loop
and should permit injection with a standard Luer-Lok syringe. Other
instruments having similar performance characteristics may also be used.
7.5.3 Reagent Bottle for Standard Storage
Heavy-wall borosilicate glass bottle with three two-way valves in the
cap. Possible sources are Rainin Instrument Co. (Catalog No. 45-3200)
or Anspec Co. (Catalog No. H8332).
7.6 Reagents and Consumable Materials
7.6.1 DOC Calibration Stock Solution (2,000 mg/L DOC)
Dissolve 0.4250 g potassium hydrogen phthalate (KHP, primary standard
grade, dried at 105°C for 2 hours) in water, add 0.10 ml phosphoric acid
(ACS reagent grade), and dilute to 100.00 ml with water. Store in an
amber bottle at 4°C. Prepare monthly.
7.6.2 Dilute Daily DOC Calibration Solutions
Using micropipets or volumetric pi pets, prepare the following calibra-
tion standards daily.
a. 0.500 mg/L DOC - dilute 0.125 ml DOC stock solution plus 0.5 mL
phosphoric acid to 500.00 mL with water.
b. 1.000 mg/L DOC - dilute 0.250 mL DOC stock solution plus 0.5 mL
phosphoric acid to 500.00 mL with water.
c. 5.000 mg/L DOC - dilute 1.250 mL DOC stock solution plus 0.5 mL
phosphoric acid to 500.00 mL with water.
d. 10.00 mg/L DOC - dilute 2.500 mL DOC stock solution plus 0.5 mL
phosphoric acid to 500.00 mL with water.
e. 30.00 mg/L DOC - dilute 3.750 mL DOC stock solution plus 0.25 mL
phosphoric acid to 250.00 mL with water.
Store in amber bottles at 4°C.
7.6.3 DOC QC Stock Solution (1,000 mg/L DOC)
Dissolve 0.5313 g KHP in water, add 0.25 mL phosphoric acid, then dilute
to 250.00 mL with water. Store in an amber bottle at 4°C. The QC stock
solution must be prepared by using an independent source of KHP. Prepare
monthly.
7.6.4 Dilute Daily DOC QC Solutions
Prepare the following QC samples daily.
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a. 0.500 mg/L DOC (Detection Limit QC Sample - DL QCCS) - dilute
0.250 ml QC stock solution plus 0.5 mL phosphoric acid to 500.00
ml with water.
b. 10.00 mg/L DOC - dilute 2.500 mL QC stock solution plus 0.25 mL
phosphoric acid to 250.00 mL with water.
c. 30.00 mg/L DOC - dilute 3.000 mL QC stock solution plus 0.1 mL
phosphoric acid to 100.00 mL with water.
Store in amber bottles at 4°C.
7.6.5 DIC Calibration Stock Solution (2,000 mg/L DIC)
Dissolve 4.4131 g sodium carbonate (Na£C03, primary standard grade,
freshly dried at 105°C for 2 hours) in water and dilute to 250.00 mL
with water. Store in a tightly capped bottle under a C02~free atmos-
phere. Prepare weekly.
7.6.6 Dilute DIC Calibration Solutions
Prepare the following calibration standards daily.
a. 0.500 mg/L DIC - dilute 0.250 mL DIC stock solution to 1.000 L
with water.
b. 1.000 mg/L DIC - dilute 0.250 mL DIC stock solution to 500.00 mL
with water.
c. 5.000 mg/L DIC - dilute 1.250 mL DIC stock solution to 500.00 mL
with water.
d. 10.00 mg/L DIC - dilute 2.500 mL DIC stock solution to 500.00 mL
with water.
f. 30.00 mg/L DIC - dilute 3.750 mL DIC stock solution to 250.00 mL
with water.
Store in tightly capped bottles under a C02~free atmosphere.
7.6.7 DIC QC Stock Solution (1,000 mg/L DIC)
Dissolve 2.2065 g Na2C03 in water and dilute to 250.00 mL with water.
Store in a tightly capped bottle under a C02~free atmosphere. The QC
stock solution must be prepared with N32C03 from a source (bottle, lot,
supplier) different from that used to prepare the calibration solution.
7.6.8 Dilute DIC QC Solutions
Prepare the following QC samples daily.
a. 0.500 mg/L DIC (Detection Limit QC Sample - DL QCCS) - dilute
0.250 mL QC stock solution to 500.00 mL with water.
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b. 10.00 mg/L DIG - dilute 2.500 mL QC stock solution to 250.00 ml
with water.
c. 30.00 mg/L DIG - dilute 3.000 mL QC stock solution to 100.00 mL
with water.
7.6.9 Potassium Persulfate Reagent (2 percent w/v)
Dissolve 20 g potassium per sul fate (I^SgOa, ACS reagent grade or better)
in water, add 2.0 mL phosphoric acid, then dilute to 1.0 L with water.
This reagent is used for DOC analyses.
7.6.10 Phosphoric Acid Reagent (5 percent v/v)
Dilute 50.0 mL concentrated phosphoric acid (ACS reagent grade) to 1.0 L
with water. This reagent is used for DIG analyses.
7.6.11 Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984).
7.7 Sample Collection, Preservation, and Storage
The sample for DOC analysis (aliquot 4) is collected, filtered, and
preserved in the field (pH adjusted to less than 2 with sul f uric acid).
Store at 4°C when not in use.
The sample for DIG analysis (aliquot 5) is collected in the field and is
not filtered or preserved. Store at 4°C and minimize atmospheric
exposure.
7.8 Calibration and Standardization
7.8.1 DOC Calibration
7.8.1.1 Set-upSet up the instrument according to the instructions provided by
the manufacturer. Adjust all liquid and gas flow rates. Turn on UV
lamp and allow the system to stabilize. The IR detector must warm up
for at least 2 hours. For best results, leave the IR detector on at
all times.
7.8.1.2 Routine CalibrationFor the range of interest (0 to 30 mg/L DOC), the
instrument is designed to be calibrated with a single 10.00 mg/L DOC
standard. The linearity of the calibration is checked with the QC
samples. If acceptable results are not obtained for the QC samples,
the instrument must be calibrated by using the procedure in section
7.8.1.3.
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Sparge the 10.00-mg/L calibration standard for 5 to 6 minutes with
C02~free gas.
Following the instructions in the operating manual, calibrate the
instrument by using three replicate analyses of the 10.00-mg/L standard.
Analyze a system blank and a reagent blank. Both must contain less
than 0.1 mg/L DOC. If either contains more DOC, then the water is
contaminated. In this case, all standards and reagents must be
prepared again with DOC-free water, and the instrument must be
recalibrated.
After sparging for 5 to 6 minutes, analyze the 0.500, 10.00, and 30.00
mg/L QC samples. Acceptable results are 0.50 ± 0.10, 10.0 ± 0.5, and
30.0 ± 1.5 mg/L, respectively. If acceptable results are not obtained
for all QC samples, the instrument calibration is inadequate (non-
linear). In this case, recalibrate the instrument by using the procedure
in section 7.8.1.3.
7.8.1.3 Nonroutine CalibrationIf the inherent instrument calibration pro-
cedure is inadequate (nonlinear over the range of interest), then the
instrument must be calibrated manually. This is done by analyzing a
series of calibration standards and by generating a calibration curve
by plotting instrument response versus standard concentration. Sample
concentrations are then determined by inverse interpolation. The
procedure is outlined in the following sections.
Sparge the 0.500, 1.000, 5.000, 10.00, and 30.00 mg/L DOC calibration
standard for 5 to 6 minutes with COg-free gas.
Erase the instrument calibration (if present). Analyze each standard
and record the uncalibrated response.
Plot the response versus standard concentration. Draw or calculate
(using linear regression) the best calibration curve.
Analyze a system blank and a reagent blank. From their response and
the calibration curve, determine their concentrations. Both must
contain less than 0.1 mg/L DOC. If either contains more than 0.1 mg/L
DOC, then the water is contaminated. In this case, the standards and
reagents must be prepared again by using DOC-free water, and the
instrument must be recalibrated.
After sparging for 5 to 6 minutes, analyze the 0.500 and 10.00 mg/L QC
samples. From their response and the calibration curve, determine the
concentration of each QC sample. Acceptable results are 0.5 ± 0.1 and
10.0 ± 0.5 mg/L, respectively. If unacceptable results are obtained,
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the calibration standards must be prepared again and reanalyzed.
Acceptable results must be obtained prior to sample analysis.
7.8.2 DIG Calibration
7.8.2.1 Set-upSet up the instrument according to the instructions provided
by the manufacturer. Adjust all liquid and gas flow rates, using 5
percent phosphoric acid as the reagent. Do not turn on the UV lamp.
Allow the system to stabilize.
7.8.2.2 Routine CalibrationThe calibration procedure is identical to that
for DOC (section 7.8.1.2) with the exception that the DIC standards
are not sparged prior to analysis.
7.8.2.3 Nonroutine CalibrationThe nonroutine calibration procedure is
identical to that for DOC (section 7.8.1.3) with the exception that
the DIC standards are not sparged prior to analysis.
7.9 Quality Control
7.9.1 In addition to the QC inherent in the calibration procedures (section
7.8), the QC procedures described in section 3.4 must be performed.
7.10 Procedure
7.10.1 DOC Analysis
7.10.1.1 Calibrate the carbon analyzer for DOC.
7.10.1.2 Sparge samples with fX^-free gas for 5 to 6 minutes (sparge gas
should have a flow of 100 to 200 cc/min). Load and analyze the
sample as directed by the instrument operating manual.
7.10.2 DIC Analysis
7.10.2.1 Calibrate the carbon analyzer for DIC.
7.10.2.2 Routine Determination
Rinse a clean syringe with sample. 'Withdraw a fresh sample portion
into the syringe. Attach a syringe filter (0.45 urn) and simultane-
ously filter the sample and inject it into the carbon analyzer.
Analyze as directed by the instrument operating manual.
For QA reasons, it is very important that the DIC is measured at the
same time pH is measured (section 4).
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7.10.2.3 Air-Equilibrated Determination
As described in section 4.10.3, equilibrate the sample with 300 ppm
C02 in air. Rinse a clean syringe with the air-equilibrated sample.
Withdraw a fresh portion of the air-equilibrated sample and attach a
syringe filter (0.45 urn). Simultaneously filter and inject the
sample into the carbon analyzer. Analyze as directed by the
instrument operating manual.
For QA reasons, it is very important that the DIG be measured at the
same time pH is measured.
7.11 Calculations
If the routine calibration procedure is satisfactory, the instrument
outputs the sample results directly in mg/L. DOC or DIC calculations are
not necessary.
If a calibration curve is necessary, determine the sample concentration
by comparing the sample response to the calibration curve. Report
results as mg/L DOC or DIC.
7.12 Precision and Accuracy
7.12.1 Precision - DOC
In a single laboratory (MERL-Cincinnati), using raw river water,
centrifuged river water, drinking water, and the effluent from a carbon
column which had concentrations of 3.11, 3.10, 1.79, and 0.07 mg/L
total organic carbon respectively, the standard deviations from 10
replicates were 0.13, 0.03, 0.02, and 0.02 mg/L, respectively (U.S.
EPA, 1983).
7.12.2 Bias - DOC
In a single laboratory (MERL-Cincinnati), using potassium hydrogen
phthalate in distilled water at concentrations between 5.0 and 1.0
mg/L total organic carbon, recoveries were 80 percent and 91 percent,
respectively (U.S. EPA, 1983).
7.13 References
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
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U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes, Method 415.2, Organic Carbon,
Total (low level) (UV promoted, persulfate oxidation). EPA-600/4-
79-020. U.S. EPA, Cincinnati, Ohio.
Xertex-Dohrman Corporation, 1984. DC-80 Automated Laboratory Total
Organic Carbon Analyzer Systems Manual, 6th Ed. Xertex-Dohrman,
Santa Clara, California.
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8.0 DETERMINATION OF TOTAL DISSOLVED FLUORIDE BY ION-SELECTIVE ELECTRODE
8.1 Scope and Application
This method is applicable to the determination of total dissolved fluoride
in natural surface waters, using a fluoride ion-selective electrode (ISE).
The applicable concentration range is 0.005 to 2 mg/L fluoride (F~).
8.2 Summary of Method
The total dissolved fluoride in a sample is determined electrometrically by
using a fluoride ion-selective electrode after addition to the sample of
a total ionic strength buffer solution (TISAB). The TISAB adjusts sample
ionic strength and pH and breaks up fluoride complexes.
The potential of the fluoride ISE varies logarithmically as a function of
the fluoride concentration. A calibration curve is prepared by measuring
the potential of known fluoride standards (after TISAB addition) and by
plotting the potential versus fluoride concentration (on a semi-log scale).
Sample concentrations are determined by comparing the sample potential to
the calibration curve.
This method is based on existing methods (U.S. EPA, 1983; Barnard and
Nordstrom, 1982; Bauman, 1971; LaZerte, 1984; Kissa, 1983; Warner and
Bressan, 1973).
8.3 Interferences
The electrode potential is partially a function of temperature. As a
result, standards and samples must be equilibrated to the same temperature
The sample pH must be in the range 5 to 7 to avoid complexation of fluoride
by hydronium (pH <5) and hydroxide (pH >7). The addition of TISAB to
samples and standards ensures that the pH is maintained in the correct
range.
Polyvalent cations may interfere by complexing fluoride, thereby preventing
detection by the electrode. The TISAB solution contains a decomplexing
agent to avoid potential interferences from polyvalent cations.
8.4 Safety
The sample types, calibration standards, and most reagents pose no hazard
to the analyst. Protective clothing (lab coat and gloves) and safety
glasses must be worn when handling concentrated sodium hydroxide.
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Fluoride is ubiquitous. Good laboratory practices and extra care must be
used in order to minimize contamination of samples and standards.
8.5 Apparatus and Equipment
8.5.1 Digital electrometer (pH/mV meter) with expanded mV scale capable of
reading 0.1 mV.
8.5.2 Combination Reference - Fluoride ion selective electrode.
8.5.3 Thermally isolated magnetic stirrer and Teflon-coated stir bar.
8.6 Reagents and Consumable Materials
Unless otherwise specified, all chemicals must be ACS reagent grade or
better. Use only plasticware (cleaned as described in Appendix A) for
reagent preparation.
8.6.1 TISAB Solution
To approximately 500 ml water in a 1-L beaker, add 57 mL glacial acetic
acid (Baker Ultrex grade or equivalent), 4 g CDTA*, and 58 g sodium
chloride (NaCl, ultrapure). Stir to dissolve, and cool to room tempera-
ture. Adjust the pH of the solution to between 5.0 and 5.5 with 5N NaOH
(about 150 ml will be required). Transfer the solution to a 1-L volu-
metric flask and dilute to the mark with water. Transfer to a clean
polyethylene (LPE) bottle. (Note: Alternatively, commercially avail-
able TISAB solution may be used.)
8.6.2 Sodium Hydroxide Solution (5N NaOH)
Dissolve 200 g NaOH in water, cool, then dilute to 1 L. Store in a
tightly sealed LPE bottle.
8.6.3 Fluoride Calibration Solutions
8.6.3.1 Concentrated Fluoride Calibration Stock Solution (1,000 mg/L F~)
Dissolve 0.2210 g of sodium fluoride (NaF, ultrapure, dried at 110'C
for 2 hours and stored in a desiccator) in water and dilute to 100.00
mL. Store in a clean LPE bottle.
*l,2-cyclohexylene dinitrilo tetraacetic acid.
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8.6.3.2 Dilute Fluoride Calibration Stock Solution (10.00 mg/L F")Dilute
1.000 mL of the concentrated fluoride calibration stock solution to
100.00 mL with water.
8.6.3.3 Dilute Fluoride Working StandardsUsing micropipets or volumetric
pipets, prepare daily a series of dilute working standards in the
range 0.0-2 mg/L F" by quantitatively diluting appropriate volumes of
the 10.00 mg/L F~ solution and TISAB solution to 50.00 mL. The
following series may be used:
mL of mL of 10.00 Resulting F~ Concentration When
TISAB mg/L F" Solution Diluted to 50.00 mL (mg/L)
5.00 0.000 0.0000
5.00 0.0500 0.0100
5.00 0.100 0.0200
5.00 0.250 0.0500
5.00 0.500 0.100
5.00 2.50 0.500
5.00 10.00 2.000
8.6.4 Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984).
8.7 Sample Collection, Preservation, and Storage
Samples are collected and filtered and are shipped to the lab in LPE
bottles. Store at 4°C when not in use.
8.8 Calibration and Standardization
8.8.1 Allow the electrometer to warm up, and ensure that the fluoride-ISE
contains adequate internal filling solution.
8.8.2 With the electrometer set to measure mV, analyze the dilute fluoride
working standards (in order of increasing concentration, beginning with
the blank) by using the procedure described in sections 8.8.2.1 through
8.8.2.3.
8.8.2.1 Prior to use and between determinations, rinse the electrode with
water until a potential of at least 200 mV is obtained. Blot dry to
avoid carryover.
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8.8.2.2 Place 20.00 ml of standard in a clean 30-mL plastic beaker. Add a
clean Teflon-coated stir bar, place on a magnetic stirrer, and stir at
medium speed.
8.8.2.3 Immerse the electrode in the solution to just above the stir bar and
observe the potential. Record the potential when a stable reading is
obtained (potential drift less than 0.1 mV/minute). Record the time
required to obtain the reading. (It may take 15 to 30 minutes to
obtain a stable reading for the low standards.)
8.8.3 Prepare a calibration curve on semi-logarithmic graph paper. Plot the
concentration of F~ (in mg/L) on the log axis versus the electrode
potential on the linear axis. Determine the slope of the line in the
linear portion of the plot. The measured slope should be within ±10
percent of the theoretical slope (obtained from the electrode manual).
If it is not, the electrode is not operating properly. Consult the
electrode manual for guidance. (Note: The calibration curve may be
nonlinear below 0.05 mg/L.)
8.9 Quality Control
The required QC procedures are described in section 3.4.
8.10 Procedure
8.10.1 Use only plasticware when performing fluoride determinations. Clean by
using the acid-free washing procedure described in Appendix A.
8.10.2 Allow samples and standards to equilibrate at room temperature.
8.10.3 Analyze fluoride standards and prepare calibration curve as described
in section 8.8.
8.10.4 Prior to use and between determinations, rinse the electrode with water
until a potential of at least 200 mV is obtained. Blot dry to avoid
carryover.
8.10.5 Place 10.00 ml of sample in a clean 30-mL plastic beaker. Add a clean
Teflon-coated stir bar, place on a magnetic stirrer, and stir at a
medium speed. Add 1.00 mL of TISAB to beaker. Record the reading when
a stable potential is obtained (drift is less than 0.1 mV/minute).
Also record the time required to reach the stable reading. (It may take
as much as 15 to 30 minutes.) This assists the analyst in detecting
electrode problems.
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8.10.6 At the end of the day, thoroughly rinse the electrode and store it in
deionized water.
8.11 Calculations
Compute the sample concentration by comparing the sample potential reading
to the calibration curve.
Report results in mg/L.
8.12 Precision and Accuracy
A synthetic sample containing 0.85 mg/L fluoride and no interferences was
analyzed by 111 analysts; the mean result was 0.84 mg/L and the standard
deviation was 0.03 mg/L (U.S. EPA, 1983).
A synthetic sample containing 0.75 mg/L fluoride, 2.5 mg/L polyphosphate,
and 300 mg/L ANC was analyzed by 111 analysts; the mean result was 0.75
mg/L fluoride and the standard deviation was 0.036 (U.S. EPA, 1983).
8.13 References
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
Barnard, W. R., and D. K. Nordstrom, 1982. Fluoride in Precipitation - I.
Methodology with the Fluoride-Selective Electrode. Atmos. Environ.,
v. 16, pp. 99-103.
Bauman, E. W., 1971. Sensitivity of the Fluoride-Selective Electrode
Below the Micromolar Range. Anal. Chim. Acta, v. 54, pp. 189-197.
Kissa, E., 1983. Determination of Fluoride at Low Concentrations with the
Ion-Selective Electrode. Anal. Chem., v. 55, pp. 1445-1448.
LaZerte, B. D., 1984. Forms of Aqueous Aluminum in BNC Catchments of
Central Ontario: A Methodological Analysis. Can. J. Fish Aquat.
Sci., v. 41, n. 5, pp. 766-776.
Warner, T. B., and D. J. Bressan, 1973. Direct Measurement of Less Than
1 Part-Per-Billion Fluoride in Rain, Fog, and Aerosols with an Ion-
Selective Electrode. Anal. Chim. Acta, v. 63, pp. 165-173.
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U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes, Method 340.2, Fluoride
(Potentiometric, Ion Selective Electrode). EPA-600/4-79-020. U.S.
EPA, Cincinnati, Ohio.
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9.0 DETERMINATION OF TOTAL DISSOLVED PHOSPHORUS
9.1 Scope and Application
This method may be used to determine concentrations of total dissolved
phosphorus in natural surface waters in the range from 0.001 to 0.200
mg/L P.
Samples preserved with HgCl2 should not be analyzed with this method.
9.2 Summary of Method
All forms of phosphorus, including organic phosphorus, are converted to
orthophosphate by an acid-persulfate digestion.
Orthophosphate ion reacts with ammonium molybdate in acidic solution to
form phosphomolybdic acid which upon reduction with ascorbic acid
produces an intensely colored blue complex. Antimony potassium tartrate
is added to increase the rate of reduction (Skougstad et al., 1979;
Gales et al., 1966; Murphy and Riley, 1962).
9.3 Interferences
Barium, lead, and silver interfere by forming a precipitate. There
is a positive interference from silica when the silica-to-total-
phosphorus ratio exceeds about 400:1 (Table 9.1).
TABLE 9.1. PERCENT RECOVERY OF TOTAL P IN THE PRESENCE OF Si02
(Skougstad et al., 1979)
==============================================================================
(mg/L)
Total P mg/L 2015105I
0.200
0.100
0.050
0.010
0.005
0.002
98
103
104
144
160
550
100
104
133
140
350
100
102
122
120
250
102
102
111
120
250
101
103
102
100
100
100
HgClp-NaCl-preserved samples give inconsistent results and therefore
should not be used.
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9.4 Safety
The calibration standards, sample types, and most reagents used in this
method pose no hazard to the analyst. Use protective clothing (lab
coat and gloves) and safety glasses when handling concentrated sulfuric
acid.
Use proper care when operating the autoclave. Follow the safety precau-
tions provided by the manufacturer.
9.5 Apparatus and Equipment
9.5.1 Autoclave.
9.5.2 Technicon AutoAnalyzer II, consisting of sampler, cartridge manifold,
proportioning pump, heating bath, colorimeter, voltage stabilizer,
recorder, and printer.
With this equipment the following operating conditions have been
found satisfactory for the range from 0.001 to 0.200 mg/L P:
Absorption cell 50 mm
Wavelength 880 nm
Cam 30/h (1:1)
Heating bath temperature 27,s°C.
9.5.3 Glass tubes with plastic caps, disposable: 18 mm by 150 mm.
9.6 Reagents and Consumable Materials
All reagents must be ACS reagent grade or equivalent.
9.6.1 Ammonium Molybdate Solution (35.6 g/L)
Dissolve 40 g ammonium molybdate [(NHA)fiMo709/,-4HoO] in 800 ml water and
,...,-, *t O / t*r £
dilute to 1 L.
9.6.2 Ascorbic Acid Solution (18 g/L)
Dissolve 18 g ascorbic acid ^5^04) in 800 ml water and dilute to 1 L.
9.6.3 Antimony Potassium Tartrate Solution (3 g/L)
Dissolve 3.0 g antimony potassium tartrate [K(SbO)C4H4Og'l/2H20] in 800
mL water and dilute to 1 L.
9.6.4 Combined Working Reagent
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Combine reagents in the order listed below. (This reagent is stable for
about 8 hours. The stability is increased if kept at 4°C):
50 mL Sulfuric acid, 2.45M
15 mL Ammonium molybdate solution
30 ml Ascorbic acid solution
5 ml Antimony potassium tartrate solution
9.6.5 Phosphate Stock Standard Solution (100 mg/L P)
Dissolve 0.4394 g potassium acid phosphate (KH2P04, dried for 12 to
16 hours over concentrated ^$04, sp gr 1.84) in water and dilute to
1,000 ml.
9.6.6 Phosphate Standard Solution I (10.00 mg/L P)
Quantitatively dilute 100.0 ml phosphate stock standard solution to
1,000 ml with water.
9.6.7 Phosphate Standard Solution II (1.000 mg/L P)
Quantitatively dilute 10.00 mL phosphate stock standard solution to
1,000 mL with water.
9.6.8 Dilute Phosphate Working Standards
Prepare a blank and 1,000 mL each of a series of working standards by
appropriate quantitative dilution of phosphate standard solutions I and
II. For example:
Phosphate standard
solution II
(mL)
Phosphate standard
solution I
(mL)
Total P
concentration
in working
standard
(mg/L)
0.0
1.00
5.00
10.00
-
-
_
0.0
-
-
-
5.0
10.0
20.0
0.000
0.001
0.005
0.010
0.050
0.100
0.200
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9.6.9 Potassium Persulfate Solution (4 g/L)
Dissolve 4.0 g potassium persulfate (K2S2Og) in water and dilute to 1 L.
9.6.10 Sulfuric Acid (2.45M)
Slowly and with constant stirring and cooling, add 136 ml concentrated
sulfuric acid (sp gr 1.84) to 800 ml water. Cool and dilute to 1 L
with water.
9.6.11 Sulfuric Acid (0.45M)
Slowly and with constant stirring and cooling, add 25.2 mL concentrated
sulfuric acid (sp gr 1.84) to 800 mL water. Cool and dilute to 1 L
with water.
9.6.12 Sulfuric Acid-Persulfate Reagent (1+1)
Mix equal volumes of 0.45M sulfuric acid and potassium persulfate solu-
tion.
9.6.13 Water Diluent
Add 1.0 ml Levor IV to 1 L water.
9.6.14 Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984).
9.7 Sample Collection, Preservation, and Storage
Samples are collected and preserved (addition of H2S04 until the pH <2).
Store samples at 4°C when not in use.
9.8 Calibration and Standardization
Analyze the series of total P standards as described in section 9.10.
Prepare a calibration curve by plotting the peak height versus standard
concentration.
9.9 Quality Control
The required QC is described in section 3.4.
-------
Section 9.0
Revision 2
Date: 11/86
Page 5 of 8
9.10 Procedure
9.10.1 It is critical that the colorimeter is optically peaked prior to first
analysis.
9.10.2 Mix each sample, pi pet a volume of it containing less than 0.002 mg
total P (10.0 ml maximum) into a disposable glass tube, and adjust the
volume to 10.0 ml_.
9.10.3 Prepare blank solution and sufficient standards, and adjust the volume
of each to 10.0 ml.
9.10.4 Add 4.0 ml acid-persulfate reagent to samples, blank, and standards.
9.10.5 Place plastic caps gently on top of tubes but do not push down. Auto-
clave for 30 minutes at 1218C and 15 psi pressure. After the samples
have cooled, the caps may be pushed down.
9.10.6 Set up manifold (Figure 9.1).
9.10.7 Allow the colorimeter, recorder, and heating bath to warm up for at
least 30 minutes or until the temperature of the heating bath reaches
37.5°C. Zero the recorder baseline while pumping all reagents through
the system.
9.10.8 Beginning with the most concentrated standard, place a complete set of
standards in the first positions of the first sample tray, with blank
solution between each standard. Fill remainder of each tray alternately
with unknown samples and blank solution.
9.10.9 Begin analysis. When the peak from the most concentrated standard
appears on the recorder, adjust the STD CAL control until the flat
portion of the peak reads full scale. Using the baseline control,
adjust each blank in the tray to read zero as it is analyzed.
9.10.10 Dilute and reanalyze samples with a total P concentration exceeding the
calibrated range.
9.11 Calculations
9.11.1 Compute the concentration of total phosphorus in each sample by compar-
ing its peak height to the calibration curve. Report results as mg/L P.
9.12 Precision and Accuracy
Data for the determination of the precision and accuracy of the method
are given in Tables 9.1 through 9.4.
-------
Section 9.0
Revision 2
Date: 11/86
Page 6 of 8
Coil No.
157-B273-03
\
0-
).
-03
5-turn coils
oooo>
37.5°C
Colorimeter
880 nm >
50 mm cell /
oooo
faste To s<
V
;
impler 4^.
vash
i receptacle
0.030 in
0.32 mL/min
0.030 in
0.32 mL/min
0.035 in
0.42 mL/min
0.030 in
0.32 mL/min
0.073 in
2.00 mL/min
0.040 in
0.60 mL/min
Air
Water
Sampl e
Combined
reagent
Wash
solution
Waste
Sampler 4
30/h
1/1 cam
Proportioning pump
Recorder
Figure 9.1. Total Dissolved Phosphorus Manifold.
-------
Section 9.0
Revision 2
Date: 11/86
Page 7 of 8
TABLE 9.2. PRECISION AND ACCURACY OF THE METHOD FOR NATURAL WATER
SAMPLES (Skougstad et al., 1979). (All data in mg/L P)
Sample n Mean Std. Dev. % Rel. Std. Dev.
4-065070
4-065080
4-066060
10
10
10
0.0347
0.1435
0.0902
0.0012
0.0031
0.0027
3.34
2.16
2.99
TABLE 9.3. PRECISION AND ACCURACY OF THE METHOD FOR ANALYST-
PREPARED STANDARDS (Skougstad et al., 1979). (All data in mg/L P)
Sample n Mean Std. Dev. % Rel. Std. Dev,
0.040
0.030
0.020
0.004
0.001
9
10
10
9
9
0.0424
0.0322
0.0172
0.0033
0.0013
0.0007
0.0006
0.0004
0.0007
0.0005
1.71
1.96
2.45
21.21
37.5
It is estimated that the RSD (coefficient of variation) of this method is
38 percent at 0.001 mg/L, 2.5 percent at 0.020 mg/L, and 2.2 percent at
0.144 mg/L.
9.13 References
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
Gales, M. E., Jr., E. C. Julian, and R. C. Kroner, 1966. Method for
Quantitative Determination of Total Phosphorus in Water. J. Am.
Water Works Assoc., v. 58, pp. 1363-1368.
Murphy, J., and J. P. Riley, 1962. A Modified Single-Solution Method for
the Determination of Phosphate in Natural Waters. Anal. Chim. Acta,
v. 27, pp. 31-36.
-------
Section 9.0
Revision 2
Date: 11/86
Page 8 of 8
Skougstad, M. W., M. J. Fishman, L. C. Friedman, D. E. Erdman, and S. S.
Duncan (eds.), 1979. Method 1-4600-78, Automated Phosphomolybdate
Colorimetric Method for Total Phosphorus. In: Methods for Deter-
mination of Inorganic Substances in Water ami Fluvial Sediments:
Techniques of Water-Resources Investigations of the United States
Geological Survey, Book 5, Chapter Al. U.S. Government Printing
Office, Washington, D.C.
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Section 10.0
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Page 1 of 7
10.0 DETERMINATION OF DISSOLVED SILICA
10.1 Scope and Application
This method is applicable for the determination of dissolved silica in
natural surface waters in the concentration range from 0.1 to 10 mg/L.
10.2 Summary of Method
Silica reacts with molybdate reagent in acid media to form a yellow
silicomolybdate complex. This complex is reduced by ascorbic acid
to form the molybdate blue color. The silicomolybdate complex may
form either as an alpha or beta polymorph, or as a mixture of both.
Because the two polymorphic forms have absorbance maxima at different
wavelengths, the pH of the mixture is kept below 2.5, which favors forma-
tion of the beta polymorph (Govett, 1961; Mullen and Riley, 1955;
Strickland, 1962).
A 1-hour digestion with l.OM NaOH is required to ensure that all the
silica is available for reaction with the molybdate reagent.
The procedure specified utilizes automated technology and is based on
existing methodology (Skougstad et al., 1979).
10.3 Interferences
Interference from phosphate, which forms a phosphomolybdate complex, is
suppressed by the addition of oxalic acid. Hydrogen sulfide must be
removed by boiling the acidified sample prior to analysis. Large
amounts of iron interfere. However, neither hydrogen sulfide nor iron
is expected in appreciable quantities.
10.4 Safety
The calibration standards, samples, and most reagents used in this
method pose no hazard to the analyst. Use protective clothing (lab coat
and gloves) and safety glasses when handling concentrated sulfuric acid
and when performing sample digestions.
10.5 Apparatus and Equipment
10.5.1 Technicon AutoAnalyzer II, consisting of sampler, cartridge manifold,
proportioning pump, colorimeter, voltage stabilizer, recorder, and
printer.
10.5.2 With this equipment the following operating conditions are recommended:
-------
Section 10.0
Revision 2
Date: 11/86
Page 2 of 7
Absorption cell _ _ ................ 15 mm
Wavelength _ 660 nm
Cam _ ........ 60/hour (6/1)
10.6 Reagents and Consumable Materials
10.6.1 Ammonium Molybdate Solution (9.4 g/L)
Dissolve 10 g ammonium molybdate ((NH4)gMo7024'4H20) in 0.05M H2S04 and
dilute to 1 L with 0.05M ^$04. Filter and store in an amber plastic
container.
10.6.2 Ascorbic Acid Solution (17.6 g/L)
Dissolve 17.6 g ascorbic acid (5^05) in 500 mL water containing 50 ml
acetone. Dilute to 1 L with water. Add 0.5 mL Levor IV solution. The
solution is stable for 1 week if stored at 4°C.
10.6.3 Hydrochloric Acid (50 percent v/v)
Slowly add 500 mL concentrated HC1 to 500 mL water.
10.6.4 Hydrochloric Acid (2 percent v/v)
Add 10 mL (concentrated) HC1 to 490 mL water.
10.6.5 Hydrofluoric Acid (HF, ACS reagent grade)
10.6.6 Levor IV Solution
Technicon No. 21-0332 or equivalent.
10.6.7 Oxalic Acid Solution (50 g/L)
Dissolve 50 g oxalic acid (C2H204'2H20) in water and dilute to 1 L.
10.6.8 Silica Standard Solution (500 mg/L Si
Dissolve 2.366 g sodium metasilicate (Na2Si03'9H20) in water and dilute
to 1.000 L. The concentration of this solution must be verified by
standard gravimetric analysis (described in section 10.8.1). Store in a
plastic bottle.
10.6.9 Silica Working Standards
Prepare a blank and 500 mL each of a series of silica working standards
by appropriate quantitative dilution of the silica stock standard solu-
tion. The following series is suggested:
-------
Section 10.0
Revision 2
Date: 11/86
Page 3 of 7
Silica stock standard Silica concentration in
solution (ml) working standard (mg/L)
0.0 0
0.200 0.200
0.500 0.500
1.00 1.00
5.00 5.00
10.0 10.0
10.6.10 Sodium Hydroxide Solution (l.OM NaOH)
Dissolve 4 g sodium hydroxide (NaOH) in water and dilute to 1 L.
10.6.11 Sulfuric Acid Solution (0.05M H2S04) (50 percent v/v H2S04)
Cautiously add 2.8 ml concentrated sulfuric acid ^SO/^, sp gr 1.84) to
water and dilute to 1 L for 0.05M H2S04- Cautiously and slowly add
500 ml H2S04 to 500 ml water. Beware of excessive heat buildup.
10.6.12 Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984).
10.7 Sample Collection. Preservation, and Storage
Samples are collected and filtered in the field and then are shipped to
the lab. Store at 4°C when not in use.
10.8 Calibration and Standardization
10.8.1 Verify the concentration of the silica stock standard solution by using
the gravimetric procedure detailed in section 10.8.1.1 through 10.8.1.7
(APHA, 1980).
10.8.1.1 Sample EvaporationAdd 5 ml of 50 percent v/v HC1 to 200.0 ml silica
stock standard. Evaporate to dryness in a 200-mL platinum evaporating
dish, in several portions if necessary, on a water bath or suspended
on an asbestos ring over a hot plate. Protect against contamination
by atmospheric dust. During evaporation, add a total of 15 ml 50 per-
cent HC1 in several portions. Evaporate sample to dryness and place
dish with residue in a 110°C oven or over a hot plate to bake for 30
minutes.
10.8.1.2 First FiltrationAdd 5 ml of 50 percent HC1, warm, and add 50 mL hot
-------
Section 10.0
Revision 2
Date: 11/86
Page 4 of 7
water. While hot, filter sample through an ashless medium-texture
filter paper, decanting as much liquid as possible. Wash dish and
residue with hot 2 percent HC1 and then with a minimum volume of
water until washings are chloride-free. Save all washings. Set
aside filter paper with its residue.
10.8.1.3 Second FiltrationEvaporate filtrate and washings from the above
operations to dryness in the original platinum dish. Bake residue in
a 110°C oven or over a hot plate for 30 minutes. Repeat steps in
section 10.8.1.2. Use a separate filter paper and a rubber policeman
to aid in transferring residue from dish to filter.
10.8.1.4 IgnitionTransfer the two filter papers and residues to a covered
platinum crucible, dry at 110°C, and ignite at 1,200°C to constant
weight. Avoid mechanical loss of residue when first charring and
burning off the paper. Cool in desiccator, weigh, and repeat ignition
and weighing until constant weight is attained. Record weight of
crucible and contents.
10.8.1.5 Volatilization with HFThoroughly moisten weighed residue with water.
Add 4 drops of 50 percent v/v ^$04 followed by 10 ml concentrated HF,
and measure the latter in a plastic graduated cylinder or by pouring an
estimated 10 ml directly from the reagent bottle. Slowly evaporate
to dryness over an air bath or hot plate in a hood, and avoid loss by
splattering. Ignite crucible to constant weight at 1,200°C. Record
weight of crucible and contents.
10.8.1.6 BlankRepeat procedures in sections 10.8.1.1 through 10.8.1.5 with a
blank sample.
10.8.1.7 Calculations
Perform the following calculations for both the standard and blank
samples.
X = weight of crucible plus contents before HF treatment (mg)
Y = weight of crucible plus contents after HF treatment (mg)
Z = weight of silica in sample (mg) = X - Y
Calculate the silica concentration in the stock standard by:
mg Si02 Z (standard) - Z (Blank) mg
L 0.200 L
10.8.2 Analyze the series of silica standards as described in section 10.10
(including digestion).
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Section 10.0
Revision 2
Date: 11/86
Page 5 of 7
10.8.3 Prepare a calibration curve by plotting the peak height versus standard
concentration.
10.9 Quality Control
The required QC is described in section 3.4.
10.10 Procedure
10.10.1 Set up the AutoAnalyzer manifold (Figure 10.1).
10.10.2 Allow colorimeter and recorder to warm up for at least 30 minutes.
Zero the recorder baseline while pumping all reagents through the
system.
10.10.3 Add 5.00 ml of l.OM NaOH to 50.00 mL of sample. Digest for one hour.
10.10.4 Beginning with the most concentrated working standard, place a complete
set of standards in the first positions of the first sample tray,
followed by a blank. Fill remainder of each sample tray with unknown
and QC samples.
10.10.5 Begin analysis. When the peak from the most concentrated working
standard appears on the recorder, adjust the STD CAL control until
the flat portion of the curve reads full scale.
10.10.6 Dilute and reanalyze any sample with a concentration exceeding the
calibrated range.
10.11 Calculations
Compute the silica concentration of each sample by comparing its
peak height to the calibration curve. Any baseline drift that may
occur must be taken into account when computing the height of a
sample or standard peak. Report results as mg/L Si03.
10.12 References
American Public Health Association, American Water Works Association,
and Water Pollution Control Foundation, 1980. Standard Methods for
the Examination of Water and Wastewater, 15th Ed. Part 425-Silica.
APHA, Washington, D.C.
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
-------
Section 10.0
Revision 2
Date: 11/86
Page 6 of 7
Govett, G.J.S., 1961. Critical Factors in the Colorimetric Determination
of Silica. Anal. Chim. Acta, v. 25, pp. 69-80.
Mullen, J. B., and J. P. Riley, 1955. The Colorimetric Determination of
Silica with Special Reference to Sea and Natural Waters. Anal.
Chim. Acta, v. 12, pp. 162-176.
Skougstad, M. W., M. J. Fishman, L. C. Friedman, D. E. Erdman, and S. S.
Duncan (eds.), 1979. Method 1-2700-78, Automated Molybdate Blue
Colorimetric Method for Dissolved Silica. In: Methods for Determi-
nation of Inorganic Substances in Water and Fluvial Sediments:
Techniques of Water-Resources Investigations of the United States
Geological Survey, Book 5, Chapter Al. U.S. Government Printing
Office, Washington, D.C.
Strickland, J.D.H., 1962. The Preparation and Properties of Silicomo-
lybdic Acid; I. The Properties of Alpha Silicomolybdic Acid. J.
Am. Chem. Soc., v. 74, pp. 852-857.
-------
Section 10.0
Revision 2
Date: 11/86
Page 7 of 7
20-turn coil
22-turn coil
I
J
OXPCOCDOOCD
Colorimeter
660 nm
15-mm cell
-0-
Waste
To sampler 4
wash
receptacle
0.030 in
0.32 ml/mm
0.035 in
0.42 mL/min
0.025 in
0.23 mL/min
0.030 in
0.32 mL/min
0.035 in
0.42 mL/min
0.073 in
2TODmL7min
0.045 in
0.80 mL/min
Air
Molybdate
Reagent
Samp! e
Oxalic
Acid
Ascorbic
Acid
Water
Waste
Proportioning pump
Recorder
Sampler 4
60/hour
6/1 cam
Figure 10.1. Silica manifold.
-------
Section 11.0
Revision 2
Date: 11/86
Page 1 of 4
11.0 DETERMINATION OF SPECIFIC CONDUCTANCE
11.1 Scope and Application
This method is applicable to natural surface waters of low ionic
strength.
The majority of streams sampled for the NSWS have a specific conduc-
tance in the range 10 to 100 uS/cm.
11.2 Summary of Method
The specific conductance in samples is measured by using a conductance
meter and conductivity cell. The meter and cell are calibrated by using
potassium chloride standards of known specific conductance (U.S. EPA,
1983).
Samples are preferably analyzed at 25°C. If they cannot be analyzed at
25°C, temperature corrections are made and results are reported at
25°C.
11.3 Interferences
Temperature variations represent the major source of potential error
in specific conductance determinations. To minimize this error,
calibration standards and samples must be measured at the same
temperature.
Natural surface waters contain substances (humic and fulvic acids,
suspended solids, etc.) which may build up on the conductivity cell.
Such a buildup interferes with the operation of the cell and must be
removed periodically by following the recommendations of the cell
manufacturer.
11.4 Safety
The calibration standards and sample types pose no hazard to the
analyst.
11.5 Apparatus and Equipment
11.5.1 Specific Conductance Meter
11.5.1.1 Digital meter with the following minimum specifications:
Range: 0.1 to 1,000 uS/cm
Readability: 0.1 uS/cm
Maximum Error: 1% of reading
Maximum Imprecision: 1% of reading
-------
Section 11.0
Revision 2
Date: 11/86
Page 2 of 4
11.5.2 Conductivity Cell
High quality glass cell with a cell constant of 1.0 or 0.1. Cells
containing platinized electrodes are recommended.
11.5.3 Thermometer
NBS-traceable thermometer with a range of 0 to 40°C and divisions of
0.1°C.
11.6 Reagents and Consumable Materials
11.6.1 Potassium Chloride Stock Calibration Solution (0.01000M KC1)
Dissolve 0.7456 g potassium chloride (KC1, ultrapure, freshly dried for
two hours at 105°C and stored in a desiccator) in water and dilute to
1.000 L. Store in a tightly sealed LPE container.
11.6.2 Potassium Chloride Calibration Solution (0.001000M KC1)
Dilute 10.00 ml KC1 stock calibration solution to 100.00 ml with water.
This solution has a theoretical specific conductance of 147.0 uS/cm at
25°C.
11.6.3 Potassium Chloride QC Solution (0.000500M KC1)
Dilute 5.00 ml 0.0100M KC1 solution (independent of the KC1 stock
calibration solution) to 100.00 ml with water. This solution has a
theoretical specific conductance of 73.9 uS/cm at 25°C.
11.6.4 Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984).
11.7 Sample Collection, Preservation, and Storage
The samples are collected in the field and are shipped to the lab in
LPE bottles without treatment. Store at 4°C when not in use.
11.8 Calibration and Standardization
11.8.1 Measure and record the specific conductance of the KC1 calibration
solution as described in section 11.10.
11.8.2 Calculate the corrected cell constant, Kc, by using the following
equation:
-------
Section 11.0
Revision 2
Date: 11/86
Page 3 of 4
147.0 uS/cm
Kc =
KClm
KClm = measured specific conductance for the KC1 calibration
solution.
The corrected cell constant, Kc, includes the calculation for the
cell constant and the temperature correction to 25°C.
11.9 Quality Control
The required QC procedures are described in section 3.4.
11.10 Procedure
11.10.1 Follow the instructions provided by the manufacturer for the operation
of the meter and cell.
11.10.2 Allow the samples and calibration standard to equilibrate to room
temperature.
11.10.3 Measure the sample temperature. If different from the standard
temperature, allow more time for equilibration.
11.10.4 Rinse the cell thoroughly with water.
11.10.5 Rinse the cell with a portion of the sample to be measured. Immerse
the electrode in a fresh portion of sample and measure its specific
conductance.
11.10.6 Rinse the cell thoroughly with water after use. Store in water.
11.10.7 If the readings become erratic, the cell may be dirty or need
replatinizing. Consult the operating manual which is provided by the
manufacturer for guidance.
11.11 Calculations
Calculate the corrected specific conductance (Sc) for each sample
using the following equation:
Sc = (Kc) (Sn.)
Kc = corrected cell constant
S,,, = measured specific conductance
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Section 11.0
Revision 2
Date: 11/86
Page 4 of 4
Report the results as specific conductance, uS/cm at 25°C.
11.12 Precision and Accuracy
Forty-one analysts in 17 laboratories analyzed 6 synthetic samples
containing increments of inorganic salts, with the following results
(U.S. EPA, 1983):
Increment, as
Specific Conductance
(uS/cm)
100
106
808
848
1,640
1,710
Precision, as
Standard Deviation
(uS/cm)
7.55
8.14
66.1
79.6
106
119
Acccuracy as
Bias U) Bias (us/cm)
-2.02
-0.76
-3.63
-4.54
-5.36
-5.08
-2.0
-0.8
-29.3
-38.5
-87.9
-86.9
In a single laboratory (EMSL-Cincinnati) using surface-water samples
with an average conductivity of 536 uS/cm at 25°C, the standard
deviation was 6 uS/cm (U.S. EPA, 1983).
11.13 References
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes, Method 120.1, Conductance.
EPA-600/4-79-020. U.S. EPA, Cincinnati, Ohio.
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Section 12.0
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Date: 11/86
Page 1 of 23
12.0 DETERMINATION OF METALS (Al, Ca, Fe, K, Mg, Mn, Na)
BY ATOMIC ABSORPTION SPECTROSCOPY
12.1 Scope and Application
Metals in solution may be readily determined by atomic absorption spectro-
scopy. The method is simple, rapid, and applicable to the determination
of Al, Ca, Fe, K, Mg, Mn, and Na in natural surface waters.
Detection limits, sensitivity, and optimum ranges of the metals vary with
the makes and models of atomic absorption spectrophotometers. The data
listed in Table 12.1, however, provide some indication of the actual con-
centration ranges measurable by direct aspiration (flame) and furnace
techniques. In the majority of instances, the concentration range shown
in the table for analysis by direct aspiration may be extended much lower
with scale expansion and, conversely, may be extended upward 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 and through solvent extraction techniques. Lower concentrations
may also be determined by using the furnace techniques. The concentration
ranges given in Table 12.1 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 he is
using furnace techniques, however, the analyst should be cautioned that
chemical reactions may occur at elevated temperatures, which may result
in either suppression or enhancement of the signal from the element being
analyzed. To ensure valid data, the analyst must examine each matrix for
interference effects (matrix spike analysis) and, if detected, must
analyze the samples by the method of standard additions.
12.2 Summary of Method
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.
When use is made of the furnace technique in conjunction with an atomic
absorption spectrophotometer, a representative aliquot of a sample is
placed in the graphite tube in the furnace, is evaporated to dryness, is
charred, and is atomized. As a greater percentage of available analyte
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Section 12.0
Revision 2
Date: 11/86
Page 2 of 23
TABLE 12.1. ATOMIC ABSORPTION CONCENTRATION RANGES3
Flame
Furnace^5*0
Metal
Detection
Limit
(mg/L)
Sensi-
tivity
(mg/L)
Optimum
Concentration
Range
(mg/L)
Detection
Limit
(ug/D
Optimum
Concentration
Range
(ug/L)
Alumi num
Calcium
Iron
Magnesium
Manganese
Potassium
Sodi urn
0.1
0.01
0.03
0.001
0.01
0.01
0.002
1
0.08
0.12
0.007
0.05
0.04
0.015
5
0.2
0.3
0.02
0.
0,
.1
,1
0.03 -
50
7
5
0.5
3
2
1
3 20 - 200
1 5-100
0.2 1 - 30
aThe concentrations shown are obtainable with any satisfactory atomic absorp-
tion spectrophotometer.
bFor furnace sensitivity values, consult instrument operating manual.
°The listed furnace values are those expected when using a 20-uL
injection and normal gas flow, except in the case of arsenic and selenium
where gas interrupt is used.
atoms are vaporized and dissociated for absorption in the tube than in 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 and thereby cause the injected
specimen to be volatilized. A monochromator isolates the characteris-
tic radiation from the hollow cathode lamp, and a photosensitive device
measures the attenuated transmitted radiation.
Dissolved metals (Ca, Fe, K, Mg, Mn, and Na) are determined in a
filtered sample (aliquot 1) by flame atomic absorption spectroscopy
(U.S. EPA, 1983).
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Section 12.0
Revision 2
Date: 11/86
Page 3 of 23
Total Al is determined in an unfiltered sample (aliquot 7) after digestion
by graphite furnace atomic absorption spectroscopy (U.S. EPA, 1983).
Total extractable Al is determined in a sample that has been treated
with 8-hydroxyquinoline and has been extracted into MIBK (aliquot 2) by
graphite furnace atomic absorption spectroscopy (Barnes, 1975; May
et al., 1979; Driscoll, 1984).
12.3 Definitions
Optimum Concentration Range
This is 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 conditions employed.
Sensitivity
Sensitivity is the concentration in milligrams of metal per liter that
produces an absorption of 1 percent.
Dissolved Metals
Dissolved metals are those constituents (metals) which can pass through
a 0.45-um membrane filter.
Total Metals
The concentration of metals is determined on an unfiltered sample
following vigorous digestion.
12.4 Interferences
12.4.1 Direct Aspiration
12.4.1.1 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 and calcium determina-
tions. Similarly, silica interference in the determination of
manganese can be eliminated by the addition of calcium.
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12.4.1.2 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.
12.4.1.3 lonization interferences occur when the flame temperature is suffici-
ently 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.
12.4.1.4 Although quite rare, spectral interference can occur when an absorb-
ing 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 ele-
ment to the atomic absorption signal. Also, interference can occur
when resonant energy from another element in a multi-element lamp or
when a metal impurity in the lamp cathode falls within the bandpass
of the slit setting with that metal being present in the sample.
This type of interference may sometimes be reduced by narrowing the
slit width.
12.4.2 Flameless Atomization
12.4.2.1 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 this effect which must be determined and taken into
consideration in the analysis of each different matrix encountered.
To verify the absence of matrix or chemical interference, a matrix
spike sample is analyzed by using 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 predeter-
mined 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
which are multiplied by the dilution factor should be compared to the
original determination. Agreement of the results (within ±10 percent)
indicates the absence of interference. Comparison of the actual
signal from the spike to the expected response from the analyte in an
aqueous standard helps confirm the finding from the dilution analysis.
Those samples which indicate the presence of interference must be
analyzed by the method of standard additions.
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12.4.2.2 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 alter-
nate wavelength outside the absorption band should eliminate this
interference. Background correction can also compensate for
nonspecific broad-band absorption interference.
12.4.2.3 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 element being analyzed.
12.4.2.4 The chemical environment of the furnace may cause certain elements to
form carbides at high temperatures. This problem is greatly reduced,
and the sensitivity is increased with the use of pyrolytically coated
graphite.
12.5 Safety
The calibration standards, sample types, and most reagents pose no
hazard to the analyst. Use protective clothing (lab coat and gloves)
and safety glasses when preparing reagents, especially when concent-
rated acids and bases are used. The use of concentrated hydrochloric
acid, ammonium hydroxide solutions, and MIBK should be restricted to a
hood.
Follow the safety precautions provided by the manufacturer when operating
the atomic absorption spectrophotometers.
Follow good laboratory practices when handling compressed gases.
12.6 Apparatus and Equipment
12.6.1 Atomic Absorption Spectrophotometer
The Spectrophotometer used shall be a single- or dual-channel, single-
or double-beam instrument having a grating monochromator, photomulti-
plier detector, adjustable slits, a wavelength range of 190 to 800 nm,
and provisions for interfacing with a strip chart recorder.
12.6.2 Burner
The burner recommended by the particular instrument manufacturer should
be used. For certain elements, the nitrous oxide burner is required.
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12.6.3 Hollow Cathode Lamps
Single element lamps are preferred, but multi-element lamps may be
used. Electrodeless discharge lamps may also be used when available.
12.6.4 Graphite Furnace
Any furnace device capable of reaching the specified temperatures is
satisfactory.
12.6.5 Strip Chart Recorder
A recorder is strongly recommended for furnace work so that there will
be a permanent record and so that any problems with the analysis such
as drift, incomplete atotnization, losses during charring, changes in
sensitivity, etc., can be easily recognized.
12.7 Reagents and Consumable Materials
12.7.1 General reagents used in each metal determination are listed in this
section. Reagents specific to particular metal determinations are
listed in the particular procedure description for that metal.
12.7.2 Concentrated Hydrochloric Acid (12M HC1)
Ultrapure grade (Baker Instra-Analyzed or equivalent) is required.
12.7.3 HC1 (1 percent v/v)
Add 5 mL concentrated HC1 to 495 ml water.
12.7.4 Nitric Acid (0.5% v/v HN03 - Ultrapure grade, Baker Instra-Analyzed or
equivalent).
Carefully dilute HN03 in water in the ratio of 0.5 to 100.
12.7.5 Stock Standard Metal Solutions
Prepare as directed in the individual metal procedures. Commercially
available stock standard solutions may also be used.
12.7.6 Dilute Calibration Standards
Prepare a series of standards of the metal by dilution of the appro-
priate stock metal solution to cover the concentration range desired.
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12.7.7 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.
12.7.8 Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984).
12.8 Sample Collection, Preservation, and Storage
Samples are collected and processed in the field. The sample for dissolved
metals (aliquot 1) is filtered through a 0.45-um membrane filter and is
then preserved by acidifying to a pH <2 with nitric acid. The sample for
total Al analysis (aliquot 7) is preserved by acidifying to a pH <2 with
nitric acid. The sample for total extractable Al (aliquot 2) is prepared
by mixing a portion of sample with 8-hydroxyquinoline followed by extrac-
tion with MIBK.
After processing, the samples are shipped to the analytical laboratory.
For aliquot 2 samples, it is the MIBK layer from the extraction that is
shipped.
12.9 Calibration and Standardization
12.9.1 The calibration procedure varies slightly with the various atomic
absorption instruments.
12.9.2 For each analyte, calibrate the atomic absorption instrument by analyz-
ing a calibration blank and a series of standards and by following the
instructions in the instrument operating manual.
12.9.3 The concentration of standards should bracket the expected sample
concentration. However, the linear range of the instrument should not
be exceeded.
12.9.4 Method of Standard Additions
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
standards containing different known amounts of the test element. The
volume of the blank and of each standard must be the same. The
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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
to zero absorbance, the point of intersection of the abscissa is the
concentration of the unknown. The abscissa on the left 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
12.1. 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 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 per-
cent), caution should be exercised.
° 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.
o The determination must be free of spectral interference and
must be corrected for nonspecific background interference.
12.10 Quality Control
The required QC procedures are described in section 3.4.
12.11 Procedure
12.11.1 General procedures for flame and furnace atomic absorption analysis
are given in sections 12.11.2 and 12.11.3. Detailed procedures for
determining Al, Ca, Fe, K, Mg, Mn, and Na are .given in sections
12.11.4 through 12.11.11.
12.11.2 Flame Atomic Absorption Spectroscopy
Differences among 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 of the manufacturer for his parti-
cular instrument. In general, after choosing the proper hollow cathode
lamp for the analysis, the lamp 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
provided by the manufacturer. Subsequently, light the flame and
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Zero
Absorbance
Sample
Addn 0
No Addn
Addn of 50%
of Expected
Amount
Wdn 2
Addn of 100%
of Expected
Amount
Addn
Addn of 150%
of Expected
Amount
Figure 12.1. Standard Addition Plot.
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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 calibrate the instrument. Aspirate the samples and determine the
concentrations either directly (if the instrument reads directly in
concentration units) or from the calibration curve.
12.11.3 Furnace Atomic Absorption Spectroscopy
Furnace devices (flameless atomization) are a most useful means of
extending detection limits. Because of differences among 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 in sections 12.11.4
through 12.11.11 (which are the recommended ones for the Perkin-Elmer
HGA-2100). In addition, the following points may be helpful.
12.11.3.1 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. These effects can be caused by the presence of
gaseous molecular species, salt particles, 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.
12.11.3.2 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 at regular inter-
vals in the analytical scheme.
12.11.3.3 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
when making use of lower atomization temperatures for shorter time
periods than those listed in this manual.
12.11.3.4 Although prior digestion of the sample in many cases is not required
provided that a representative aliquot of sample can be pipeted into
the furnace, it provides for a more uniform matrix and possibly
lessens matrix effects.
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12.11.3.5 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
should be reanalyzed. The use of multiple injections can improve
accuracy and can help detect furnace pipetting errors.
12.11.4 Procedure for Determination of Total Aluminum
12.11.4.1 SummaryA portion of sample is digested, and digestate is analyzed
for Al by furnace atomic absorption spectroscopy (U.S. EPA, 1983).
12.11.4.2 Preparation of Aluminum Standard Solutions
Aluminum stock solution (1000 mg/L Al)Carefully weigh 1.000 gram
aluminum metal (analytical reagent grade). Add 15 ml concentrated
HC1 and 5 ml concentrated HN03 to the metal, cover the beaker, and
warm gently. When metal is completely dissolved, transfer solu-
tion quantitatively to a 1-L volumetric flask and bring to volume
with water. Alternatively, a commercially available, certified Al
standard may be used.
Prepare dilutions of the stock solution to be used as calibration
standards at the time of analysis. These solutions are also to be
used for "standard additions."
The calibration standard should be prepared in 0.5 percent (v/v)
HN03.
12.11.4.3 Sample PreparationThe sample must be digested prior to analysis.
Because of the low concentrations of analyte expected, contamination
from atmospheric sources can be a major problem. To avoid contami-
nation, all preparations must be performed in a laminar flow hood.
Quantitatively transfer a 50.00 ml aliquot of the well-mixed sample
to a Griffin beaker. Add 3.0 ml of concentrated nitric acid. Place
the beaker on a hot plate and cautiously evaporate to near dryness,
making certain that the sample does not boil. (DO NOT BAKE.) Allow
the beaker to cool, then again add 3.0 ml of concentrated nitric
acid. Cover the beaker with a watch glass and return to the hot
plate. Increase the temperature of the hot plate until a gentle
reflux action occurs. Continue refluxing, adding acid as necessary,
until the digestion is complete (indicated by a light-colored
residue or no change in appearance with continued refluxing). When
complete, evaporate to near dryness. Allow to cool. Add 0.5 ml of
50 percent nitric acid and warm slightly to dissolve any precipitate
or residue resulting from evaporation. Wash down the beaker walls
and watch glass with water. Quantitatively filter the sample (to
remove silicates and other insoluble materials) and adjust to 50.00
mL. The sample is now ready for analysis.
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12.11.4.4 Suggested Instrument Conditions (General)
Drying time and temperature--30 seconds at 125°C.
Ashing time and temperature30 seconds at 1,300°C.
Atomizing time and temperaturelO seconds at 2,700°C.
Purge gas atmosphereArgon.
Wavelength--309.3 nm.
Other operating conditions should be set as specified by the
particular instrument manufacturer.
12.11.4.5 Analysis Procedure
Calibrate the instrument as directed by the instrument manufacturer.
Analyze the samples (including required QC samples).
If a sample concentration exceeds the linear range, dilute (with
acidic media) and reanalyze.
Report results as mg/L Al.
12.11.4.6 Notes
The above instrument conditions are for a Perkin-Elmer HGA-2100 and
are based on the use of a 20 uL injection, continuous-flow purge
gas, and nonpyrolytic graphite.
Background correction may be required if the sample contains a high
level of dissolved solids.
It has been reported that chloride ion and that nitrogen used as a
purge gas suppress the aluminum signal. Therefore, the use of
halide acids and nitrogen as a purge gas should be avoided.
The ashing temperature can be increased to 1,500 to 1,700°C by
adding 30 ug magnesium nitrate (Mg(N03)2) (Manning et al., 1982).
If blanks indicate that sample contamination is occuring, the use of
Teflon labware is recommended.
12.11.5 Procedure for Determination of Total Extractable Aluminum
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12.11.5.1 Summary Samples for extractable aluminum are prepared in the field
and are obtained as the 8-hydroxyquinoline complex in MIBK. The
MIBK solution is analyzed for aluminum by graphite furnace atomic
absorption (GFAA) (Barnes, 1975; May et al . , 1979; Driscoll, 1984).
12.11.5.2 Preparation of Reagents
Glacial acetic acid (HOAc, 18M) --Baker Ultrex grade or equivalent.
Ammonium hydroxide (NHflOH, 5M) Baker Ultrex grade or equivalent.
Sodium acetate solution (NaOAc, 1.0M)~Dissolve 8.2 g NaOAc (Alfa
Ultrapure grade or equivalent) in 100 ml water.
Methyl isobutyl ketone (MIBK)--HPLC grade or equivalent.
Phenol red indicator solution (0.04 percent w/v) ACS reagent grade.
Hydrochloric acid (HC1, 12M)--Baker Ultrex grade or equivalent.
2.5 M HC1 Dilute 208 ml of 12 M HC1 to 1.0 L.
NH//NH3 bufferAdd 56 ml glacial acetic acid to 75 ml of 5M NH4OH
dilute to 250 ml. Adjust pH to 8.3 by using NH4OH or HOAc.
8-hydroxyquinoline solution (10 g/L)--Dissolve 5 grams of 8-hydroxy-
quinoline (99 plus percent purity) in 12.5 ml HOAc, then dilute to
500 ml.
8-hydroxyquinoline sodium acetate reagent Mix, in order, 10 ml
l.OM NaOAc, 50 ml water, and 10 mL hydroxyquinoline solution. This
reagent must be prepared daily.
12.11.5.3 Preparation of Aluminum Standard Solutions
Aluminum stock solution Prepare as described in section 12.11.4.2.1,
Dilute calibration standards Daily, quantitatively dilute the Al
stock solution to prepare a series of calibration standards over
the range 0 to 0.1 mg/L Al . A blank must be prepared. Prior to
analysis, the blank, standards (and any QC samples) must be
extracted.
Pipet 25.00 ml of a calibration standard (or calibration blank or
QC sample) into a clean 50-mL separatory funnel (or a clean 50-mL
disposable centrifuge tube with cap).
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Add 2 to 3 drops phenol red indicator and 5.00 ml 8-hydroxy-
quinoline NaOAc reagent. Swirl to mix.
Rapidly adjust the pH to 8 by dropwise additions of 5M N^OH until
the solution turns red. Immediately add 2.0 ml NH4+/NH3 buffer
and 10 ml MIBK. Cap and shake vigorously for 7 to 10 seconds
with a rapid, end-to-end motion. Be careful of pressure buildup.
Allow the phases to separate (10 to 15 seconds) and isolate the
MIBK layer. If an emulsion forms, separation can be hastened by
centrifugation. Keep the MIBK layer tightly capped to prevent
evaporation.
12.11.5.4 Suggested Instrument Conditions (General)
Drying cycleRamp 10 seconds, hold 10 seconds.
Drying temperature100°C.
Ashing cycleRamp 5 seconds, hold 20 seconds.
Ashing temperature--!,500°C.
Atomization cycleHold 5 seconds (no ramp, max. power heating).
Atomi zati on temperature2,500°C.
Purge gasArgon at 20 cc/minute.
LampAl HC1 at 25 mA.
Wavelength309.3.
Graphite tubeNonpyrolytic.
Sample size25 uL.
These operating conditions are for a Perkin-Elmer 5000 with a
HGA-500 graphite furnace and AS-40 autosampler.
12.11.5.5 Analysis Procedure
Calibrate the instrument as directed by the instrument manufacturer.
Analyze the samples (including required QC samples).
If a sample concentration exceeds the linear range, dilute with MIBK
and reanalyze.
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Report results as mg/L Al.
12.11.5.6 Note - By using the same volumes for standards as for samples,
concentration factors are taken into account.
12.11.6 Procedure for Determination of Dissolved Calcium
12.11.6.1 Summary--The samples (filtered and preserved in the field) are
analyzed by flame atomic absorption spectroscopy for Ca (U.S. EPA,
1983).
12.11.6.2 Preparation of Reagents
Lanthanum chloride matrix modifier solutionDissolve 29 g La203,
slowly and in small portions, in 250 ml concentrated HC1 (Caution:
Reaction is violent) and dilute to 500 ml with water.
12.11.6.3 Preparation of Calcium Standard Solutions
Calcium stock solution (500 mg/L Ca)--Suspend 1.250 g CaC03
(analytical reagent grade, dried at 180°C for 1 hour before weighing)
in water and dissolve cautiously with a minimum of dilute HC1.
Dilute to 1,000 mL with water.
Dilute calibration standardsDaily, quantitatively prepare a series
of dilute Ca standards from the calcium stock solution to span the
desired concentration range.
12.11.6.4 Suggested Instrumental Conditions (General)
Calcium hollow cathode lamp; wavelength, 422.7 nm; fuel, acetylene;
oxidant, air; type of flame, reducing.
12.11.6.5 Analysis Procedure
To each 10.0 mL volume of dilute calibration standard, blank, and
sample add 1.00 mL LaCl3 solution (e.g., add 2.0 mL Lads solution
to 20.0 mL sample).
Calibrate the instrument as directed by the manufacturer.
Analyze the samples.
Dilute and reanalyze any samples with a concentration exceeding the
calibrated range.
Report results as mg/L Ca.
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12.11.6.6 Notes
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, both standards and samples are prepared
in dilute acid solution. Concentrations of magnesium greater than
1,000 mg/L also cause low calcium values. Concentrations of up to
500 mg/L each of sodium, potassium, and nitrate cause no
interference.
Anionic chemical interferences can be expected if lanthanum is not
used in samples and standards.
The nitrous oxide-acetylene flame will provide two to five times
greater sensitivity and freedom from chemical interferences.
lonization interferences should be controlled by adding a large
amount of alkali to the sample and standards. The analysis appears
to be free from chemical suppressions in the nitrous oxide-acetylene
flame.
The 239.9 nm line may also be used. This line has a relative
sensitivity of 120.
12.11.6.7 Precision and Accuracy
In a single laboratory (EMSL-Cincinnati), when use was made of
distilled water spiked at concentrations of 9.0 and 36 mg Ca/L, the
standard deviations were ±0.3 and ±0.6, respectively. Recoveries at
both these levels were 99 percent.
12.11.7 Procedure for Determination of Dissolved Iron
12.11.7.1 SummaryThe samples (filtered and preserved in the field) are
analyzed by flame atomic absorption spectroscopy (U.S. EPA, 1983).
12.11.7.2 Preparation of Iron Standard Solutions
Fe stock solution (1,000 mg/L Fe)Carefully weigh 1.000 g pure iron
wire (analytical reagent grade) and dissolve in 5 mL concentrated
HN03, warming if necessary. When iron is completely dissolved,
bring volume of solution to 1 L with water.
Dilute calibration standardsDaily, quantitatively prepare a series
of calibration standards spanning the desired concentration range.
Match the acid content of the standards to that of the samples
(ca. 0.1 percent (v/v)
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12.11.7.3 Suggested Instrumental Conditions (General)
Iron hollow cathode lamp; wavelength, 248.3 nm; fuel, acetylene;
oxidant, air; type of flame, oxidizing.
12.11.7.4 Analysis Procedure
Calibrate the instrument as directed by the instrument manufacturer.
Analyze the samples.
Dilute and reanalyze any samples with concentrations exceeding the
calibrated range.
Report results in mg/L Fe.
12.11.7.5 Notes
The following lines may also be used: 248.8 nm, relative sensi-
tivity 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.
12.11.7.6 Precision and Accuracy
An interlaboratory 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 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 Value
(ug/L)
840
700
350
438
24
10
Mean Value
(M9/D
855
680
348
435
58
48
Standard
Deviation
(U9/D
173
178
131
183
69
69
Accuracy as
% Bias
1.8
-2.8
-0.5
-0.7
141
382
12.11.8 Procedure for Determination of Dissolved Magnesium
12.11.8.1 SummaryThe samples (filtered and preserved in the field) are
analyzed by flame atomic absorption spectroscopy for Mg.
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12.11.8.2 Preparation of Reagents
Lanthanum chloride solution Dissolve 29 g l^C^, slowly and in
, s
small portion's, in 250 ml concentrated HC1 (Caution: Reaction is
violent) and dilute to 500 ml with water.
12.11.8.3 Preparation of Magnesium Standard Solutions
Stock solution (500 mg/L Mg)--Dissolve 0.829 g magnesium oxide, MgO
(analytical reagent grade), in 10 ml of HN03 and dilute to 1 L with
water .
Dilute calibration standards Daily, quantitatively prepare from the
Mg stock solution a series of Mg standards that spans the desired
concentration range.
12.11.8.4 Suggested Instrumental Conditions (General)
Magnesium hollow cathode lamp; wavelength, 285.2 nm; fuel, acetylene;
oxidant, air; type of flame, oxidizing.
12.11.8.5 Analysis Procedure
To each 10.0 ml dilute calibration standard, blank, and sample, add
1.00 ml LaCl3 solution (e.g., add 2.0 ml LaCl3 solution to 20.0 ml
sample) .
Calibrate the instrument as directed by the" manufacturer.
Analyze the samples.
Dilute and reanalyze any samples with a concentration exceeding the
linear range.
Report results as mg/L Mg.
12.11.8.6 Notes
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 in surface
waters (0.1 to 20 mg/L), it is suggested that either the 202.5 nm
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line be used or the burner head be rotated. A 90° rotation of the
burner head will produce approximately one-eighth the normal
sensitivity.
12.11.8.7 Precision and Accuracy
In a single laboratory (EMSL-Cincinnati), when use is made of
distilled water spiked at concentrations of 2.1 and 8.2 mg/L Mg, the
standard deviations were ±0.1 and ±0.2, respectively. Recoveries at
both of these levels were 100 percent.
12.11.9 Procedure for Determination of Dissolved Manganese
12.11.9.1 SummaryThe samples (filtered and preserved in the field) are
analyzed by flame atomic absorption spectroscopy for Mn (U.S. EPA,
1983).
12.11.9.2 Preparation of Manganese Standard Solutions
Mn stock solution (1,000 mg/L Mn)--Carefully weigh 1.000 g manganese
metal (analytical reagent grade) and dissolve in 10 ml of HN03.
When metal is completely dissolved, dilute solution to 1 liter with
1 percent (v/v) HC1.
Dilute calibration standardsDaily, quantitatively prepare a series
of calibration standards spanning the desired concentration range.
Match the acid content of the standards to that of the samples
(ca. 0.1 percent (v/v) HN03).
12.11.9.3 Instrumental Conditions (General)
Manganese hollow cathode lamp; wavelength, 279.5 nm; fuel, acetylene;
oxidant, air; type of flame, oxidizing.
12.11.9.4 Analysis Procedure
Calibrate the instrument as directed by the manufacturer.
Analyze the samples.
Dilute and reanalyze any samples with a concentration exeeding the
calibrated range.
Report results as mg/L Mn.
12.11.9.5 Notes
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Section 12.0
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The line at 403.1 nm may also be used. This line has a relative
sensitivity of 10.
12.11.9.6 Precision and Accuracy
An interlaboratory 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 aluminum, cadmium, chromium, copper, iron,
manganese, lead, and zinc were added to natural water samples. The
statistical results for manganese were as follows:
Standard Accuracy
Number True Value Mean Value Deviation as
of Labs (ug/D (ug/L) (ug/L) % Bias
77 426 432 70 1.5
78 469 474 97 1.2
71 84 86 26 2.1
70 106 104 31 -2.1
55 11 21 27 93
55 17 21 20 22
12.11.10 Procedure for Determination of Dissolved Potassium
12.11.10.1 SummaryThe samples (filtered and preserved in the field) are
analyzed by flame atomic absorption spectrpscopy for K (U.S. EPA,
1983).
12.11.10.2 Preparation of Potassium Standard Solutions
Potassium stock solution (100 mg/L K)Dissolve 0.1907 g KC1
(analytical reagent grade, dried at 110°C) in water and bring
volume of solution to 1 L.
Dilute calibration standardsDaily, quantitatively prepare a
series of calibration standards spanning the desired concentration
range. Match the acid content of the standards to that of the
samples (ca. 0.1 percent (v/v) HN03).
12.11.10.3 Suggested Instrumental Conditions (General)
Potassium hollow cathode lamp; wavelength, 766.5 nm; fuel,
acetylene; oxidant, air; type of flame, slightly oxidizing.
12.11.10.4 Analysis Procedure
Calibrate the instrument as directed by the manufacturer.
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Section 12.0
Revision 2
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Page 21 of 23
Analyze the samples.
Dilute and reanalyze any sample with a concentration exceeding the
calibrated range.
Report results as mg/L K.
12.11.10.5 Notes
In air-acetylene or other high-temperature flames (>2,800°C),
potassium can experience partial ionization which indirectly
affects absorption sensitivity. The presence of other alkali salts
in the sample can reduce this ionization and thereby enhance
analytical results. The ionization suppress!ve effect of sodium is
small if the ratio of Na to K is under 10. Any enhancement which is
due to 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 cesium 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 in surface
waters (0.1 to 20 mg/L), it is suggested that the burner head be
rotated. A 90° rotation of the burner head provides approximately
one-eighth the normal sensitivity.
12.11.10.6 Precision and Accuracy
In a single laboratory (EMSL-Cincinnati), when use was made of
distilled water samples spiked at concentrations of 1.6 and 6.3
mg/L K, the standard deviations were ±0.2 and ±0.5, respectively.
Recoveries at these levels were 103 percent and 102 percent,
respectively.
12.11.11 Procedure for Determination of Dissolved Sodium
12.11.11.1 SummaryThe samples (filtered and preserved in the field) are ana-
lyzed by flame atomic absorption spectroscopy for Na (U.S. EPA,
1983).
12.11.11.2 Preparation of Sodium Standard Solutions
Sodium stock solution (1,000 mg/L Na)Dissolve 2.542 g NaCl
(analytical reagent grade, dried at 140°C) in water and bring the
volume of the solution to 1 L.
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Section 12.0
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Dilute calibration standardsDaily, quantitatively prepare a
series of calibration standards spanning the desired concentration
range. Match the acid content of the standards to that of the
samples (ca. 0.1 percent (v/v) HN03).
12.11.11.3 Suggested Instrumental Conditions (General)
Sodium hollow cathode lamp; wavelength, 589.6 nm; fuel, acetylene;
oxidant, air; type of flame, oxidizing.
12.11.11.4 Analysis Procedure
Calibrate the instrument as directed by the manufacturer.
Analyze the samples.
Dilute and reanalyze any samples with a concentration exceeding the
calibrated range.
Report results as mg/L Na.
12.11.11.5 Notes
The 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 sensitivity by reducing the extent
of ionization of this easily ionized metal. lonization may also be
controlled by adding potassium (1,000 mg/L) to both standards and
samples.
12.11.11.6 Precision and Accuracy
In a single laboratory (EMSL-Cincinnati), when use is made of
distilled water samples spiked at levels of 8.2 and 52 mg/L Na, the
standard deviations were ±0.1 and ±0.8, respectively. Recoveries
at these levels were 102 percent and 100 percent.
12.12 Calculations
Generally, instruments are calibrated to output sample results
directly in concentration units. If they do not, then a manual cali-
bration curve must be prepared, and sample concentrations must be
determined by comparing the sample signal to the calibrated curve.
If dilutions were performed, the appropriate factor must be applied to
sample values.
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Section 12.0
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Page 23 of 23
Report results as mg/L for each analyte.
12.13 References
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
Barnes, R. B., 1975. The Determination of Specific Forms of Aluminum
in Natural Water. Chem. Geol., v. 15, pp. 177-191.
Driscoll, C. T., 1984. A Procedure for the Fractionation of Aqueous
Aluminum in Dilute Acidic Waters. Int. J. Environ. Anal. Chem.,
v. 16, pp. 267-283.
Manning, D. C., W. Slavin, and 6. R. Carnick, 1982. Investigation of
Aluminum Interferences Using the Stabilized Temperature Platform
Furnace. Spectrochim. Acta, Part B, v. 37b, n. 4, pp. 331-341.
May, H. M., P. A. Helmke, and M. L. Jackson, 1979. Determination of
Mononuclear Dissolved Aluminum in Near-Neutral Waters. Chem.
Geol., v. 24, pp. 259-269.
U.S. Environmental Protection Agency, 1983 (revised). Methods for
Chemical Analysis of Water and Wastes, Method 200.0, Atomic Absorp-
tion Methods. EPA 600/4-79-020. U.S. EPA, Cincinnati, Ohio.
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Section 13.0
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Page 1 of 10
13.0 DETERMINATION OF DISSOLVED METALS (Ca, Fe, Mg, and Mn) BY INDUCTIVELY
COUPLED PLASMA EMISSION SPECTROSCOPY
13.1 Scope and Application
This method is applicable to the determination of dissolved Ca, Fe,
Mg, and Mn in natural surface waters.
Table 13.1 lists the recommended wavelengths and typical estimated
instrumental detection limits using conventional pneumatic nebulization
for the specified elements. Actual working detection limits are
sample-dependent, and as the sample matrix varies, these concentrations
may also vary.
Because of the differences among 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.
13.2 Summary of Method
The method describes a technique for the simultaneous or sequential
determination of Ca, Fe, Mg, and Mn in samples collected for the
NSWS. The method is based on the measurement of atomic emission by
optical spectroscopy. 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
wavelengths. 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 stand-
ards (U.S. EPA, 1983; Fassel, 1982).
A background correction technique is required to compensate for vari-
able background contribution to the determination of trace elements.
Background must be measured adjacent to analyte lines during sample
analysis. The position selected for the background intensity measure-
ment, on either or both sides of the analytical line, will be deter-
mined 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 consulted for guidance.
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Section 13.0
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TABLE 13.1. RECOMMENDED WAVELENGTHS3 AND ESTIMATED
INSTRUMENTAL DETECTION LIMITS
============================================================================:
Element Wavelength (nm) Estimated detection limit (ug/L)b
Calcium
Iron
Magnesium
Manganese
317.933
259.940
279.079
257.610
10
7
30
2
aThe wavelengths listed are recommended because of their sensitivity and over-
all acceptance. Other wavelengths may be substituted if they can provide the
needed sensitivity and are treated with the same corrective techniques for
spectral interference (EPA 1979).
bThe 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.
The possibility of additional interferences named in 13.3.1 should also
be recognized, and appropriate corrections should be made.
13.3 Interferences
Several types of interference effects may contribute to inaccuracies in
the determination of trace elements. They are summarized in sections
13.3.1 through 13.3.1.3.
13.3.1 Spectral interferences can be categorized as (1) overlap of a
spectral line from another element; (2) unresolved overlap of mole-
cular 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 by utilizing a computer
correction of the raw data, which would require 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 multi-element
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
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Section 13.0
Revision 2
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Page 3 of 10
Table 13.2 are some interference effects for the recommended wave-
lengths given in Table 13.1. The interference information is
expressed as analyte concentration eqivalents (i.e., false analyte
concentrations) arising from 100 mg/L of the interfering element.
The values in the table are only approximate and should be used as a
guide for determining potential interferences. Actual values must be
determined for each analytical system when necessary.
Only those interferents listed were investigated. The blank spaces
in Table 13.2 indicate that measurable interferences were not
observed for the interferent concentrations listed in Table 13.3.
Generally, interferences were discernible if they produced peaks or
background shifts corresponding to 2 to 5 percent of the peaks gene-
rated by the analyte concentrations (also listed in Table 13.3).
13.3.2 Physical interferences are generally considered to be effects associ-
ated with the sample nebulization and transport processes. Changes
in viscosity and surface tension can cause significant inaccuracies,
especially in samples that contain high dissolved solids or acid
concentrations. 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.
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, or sample dilution have been used to control this problem.
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.
13.3.3 Chemical interferences are characterized by molecular compound
formation, ionization effects, and solute vaporization effects.
Normally these effects are negligible with the ICP technique. If
observed, they can be minimized by careful selection of operating
conditions (i.e., incident power, observation position, and so
forth), by buffering of the sample, by matrix matching, and by stan-
dard addition procedures. These types of interferences can be highly
dependent on matrix type and on the specific analyte element.
13.3.4 Whenever a new or unusual sample matrix is encountered, a series of
tests should be performed prior to reporting concentration data for
analyte elements. These tests, as outlined in 13.3.4.1 through
13.3.4.4, will ensure that neither positive nor negative interference
effects are operative on any of the analyte elements, which would
distort the accuracy of the reported values.
-------
TABLE 13.2. ANALYTE CONCENTRATION EQUIVALENTS (mg/L) ARISING FROM
INTERFERENTS AT THE 100 mg/L LEVEL
Analyte Wavelength, ' Interferent
(nm) '
Al Ca Cr Cu Fe Mg Mn Ni Ti V
Calcium 317.933 0.08 0.01 0.01 0.04 -- 0.03 0.03
Iron 259.940 -- 0.12
Magnesium 279.079 -- 0.02 0.11 -- 0.13 0.25 0.07 0.12
Manganese 257.610 0.005 ~ 0.01 0.002 0.002
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Section 13.0
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Page 5 of 10
TABLE 13.3. INTERFERENT AND ANALYTE ELEMENTAL CONCENTRATIONS USED
FOR INTERFERENCE MEASUREMENTS IN TABLE 13.2
Analytes (mg/L) Interferents (mg/L)
Ca
Fe
Mg
Mn
1
1
1
1
Al
Ca
Cr
Cu
Fe
Mg
Nn
Ni
Ti
V
1,000
1,000
200
200
1,000
1,000
200
200
200
200
13.3.4.1 Serial DilutionIf 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 that has been established for that matrix). If not, a
chemical or physical interference effect should be suspected.
13.3.4.2 Spiked AdditionThe 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 overlap is suspected, use of computerized compensation,
an alternate wavelength, or comparison with an alternate method is
recommended.
13.3.4.3 Comparison with Alternate Method of AnalysisWhen a new sample
matrix is being investigated, a comparison test may be performed with
other analytical techniques, such as atomic absorption spectrometry
or other approved methodology.
13.3.4.4 Wavelength Scanning of Analyte Line RegionIf the appropriate equip-
ment is available, wavelength scanning can be performed to detect
potential spectral interferences.
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Section 13.0
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Page 6 of 10
13.4 Safety
Generally, the calibration standards, sample types, and most reagents
pose no hazard to the analyst. Protective clothing (lab coats and
gloves) and safety glasses should be worn when handling concentrated
acids.
Follow the instrument safety recommendations provided by the manufacturer
for the operation of the ICP.
The toxicity or carcinogenicity of each reagent used in this method has
not been precisely defined. 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 (NIOSH, 1977;
OSHA, 1976; ACS, 1979) for the information of the analyst.
13.5 Apparatus and Equipment
Inductively Coupled Plasma-Atomic Emission Spectrometer
Computer-controlled ICP emission spectrometer with background correc-
tion capability shall be used.
13.6 Reagents and Consumable Materials
13.6.1 Acids used in the preparation of standards and for sample processing
must be ultra-high purity grade or equivalent (e.g., Baker Ultrex grade
or SeaStar Ultrapure grade).
13.6.1.1 Hydrochloric Acid, concentrated (sp gr 1.19)
13.6.1.2 Hydrochloric Acid (50 percent v/v)Add 500 ml concentrated HC1 to
400 ml water and dilute to 1 L.
13.6.1.3 Nitric Acid, concentrated (sp gr 1.41)
13.6.1.4 Nitric Acid (50 percent v/v)--Add 500 ml concentrated HN03 to 400 ml
water and dilute to 1 L.
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Section 13.0
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Date: 11/86
Page 7 of 10
13.6.2 Water
Water must meet the specifications for Type I Reagent Water given in
ASTM D 1193 (ASTM, 1984).
13.6.3 Standard Stock Solutions
Solutions may be purchased or prepared from ultra-high purity g^ade
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 swallowed.
Wash hands thoroughly after handling.
13.6.3.1 Calcium Stock Standard Solution (100 mg/D Suspend 0.2498 g
(dried at 180°C for 1 hour before weighing) in water and dissolve
cautiously with a minimum amount of 50 percent HN03. Add 10.0 mL
concentrated HN03 and dilute to 1,000 mL with water.
13.6.3.2 Iron Stock Standard Solution (100 mg/L)~Dissolve 0.1430 g Fe203 in a
warm mixture of 20 mL 50 percent HC1 and 2 mL concentrated HN03-
Cool, add an additional 5 mL concentrated HN03, and dilute to 1,000
mL with water.
13.6.3.3 Magnesium Stock Standard Solution (100 mg/L) Dissolve 0.1658 g MgO
in a minimum amount of 50 percent HN03. Add 10.0 mL concentrated
HN03 and dilute to 1,000 mL with water.
13.6.3.4 Manganese Stock Standard Solution (100 mg/D Dissolve 0.1000 g of
manganese metal in an acid mixture consisting of 10 mL concentrated
HC1 and 1 mL concentrated HN03, and dilute to 1,000 mL with water.
13.7 Sample Handling, Preservation, and Storage
i
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 con-
tacts 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 Appendix A.
Samples are collected and processed in the field. A portion (aliquot 3)
of each sample is filtered and acidified (0.1-mL increments) with nitric
acid until the pH <2. The processed samples are then sent to the lab and
are analyzed (as is) for dissolved metal (Ca, Fe, Mg, Mn) content.
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Section 13.0
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Page 8 of 10
13.8 Calibration and Standardization
Prepare a calibration blank and a series of dilute calibration stan-
dards from the stock solutions to span the expected sample concentra-
tion range. Match the acid content of the standards to that of the
samples (written on the sample label, ca. 0.2 percent). A multi-
element standard may be prepared.
The calibration procedure varies with the various ICPES instruments.
Calibrate the ICPES for each analyte following the instrument opera-
ting conditions.
13.9 Quality Control
The required QC procedures are described in section 3.4.
13.10 Procedure
13.10.1 Set up instrument as recommended by the manufacturer or as experience
dictates. The instrument must be allowed to become thermally stable
before beginning (10 to 30 minutes).
13.10.2 Profile and calibrate instrument according to the recommended procedures
provided by the instrument 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.)
13.10.3 Begin sample analysis by flushing the system with the calibration blank
solution between each sample. Remember to analyze required QC samples.
13.10.4 Dilute and reanalyze any samples with a concentration exceeding the
calibration range.
13.11 Calculations
Generally, instruments are calibrated to output sample results directly
in concentration units. If not, then a manual calibration curve must
be prepared, and sample concentrations must be determined by comparing
the sample signal to the calibrated curve.
If dilutions were performed, the appropriate factor must be applied to
sample values.
Report results as mg/L for each analyte.
-------
TABLE 13.4. INDUCTIVELY COUPLED PLASMA PRECISION AND ACCURACY DATA^
Element
Mn
Fe
True
Value
(ug/D
350
600
Sampl e 1
Mean
Reported
Value
(ng/L)
345
594
Mean
ZRSD
2.7
3.0
True
Value
(ug/D
15
20
Sampl e 2
Mean
Reported
Value
(ug/D
15
19
Mean
SRSD
6.7
15
True
Value
(ug/D
100
180
Sample 3
Mean
Reported
Value
(ug/L)
99
178
Mean
%RSD
3.3
6.0
aNot all elements were analyzed by all laboratories.
Ca and Mg were not determined.
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Section 13.0
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Page 10 of 10
13.12 Precision and Accuracy
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 13.4 lists the true value, the mean
reported value, and the mean %RSD (U.S. EPA, 1983).
13.13 References
American Chemical Society, 1979. Safety in Academic Laboratories,
3rd ed. Committee on Chemical Safety, ACS, Washington, D.C.
American Society for Testing and Materials, 1984. Annual Book of ASTM
Standards, Vol. 11.01, Standard Specification for Reagent Water,
D 1193-77 (reapproved 1983). ASTM, Philadelphia, Pennsylvania.
Department of Health, Education, and Welfare, 1977. Carcinogens -
Working with Carcinogens. No. 77-206. DHEW, Public Health Service,
Center for Disease Control, National Institute for Occupational
Safety and Health, Cincinnati, Ohio.
Fassel, V. A., 1982. Analytical Spectroscopy with Inductively Coupled
Plasmas - Present Status and Future Prospects. In: Recent Advances
in Analytical Spectroscopy. Pergamon Press, OxfoFd and New York.
Occupational Safety and Health Administration, 1976. OSHA Safety and
Health Standards, General Industry. OSHA 2.206 (29 CFR 1910). OSHA.
U.S. Environmental Protection Agency, 1979. Inductively Coupled Plasma -
Atomic Emission Spectroscopy - Prominent Lines. EPA-600/4-79-017.
U.S. EPA, Cincinnati, Ohio.
U.S. Environmental Protection Agency, 1983 (revised). Methods for Chemi-
cal Analysis of Water and Wastes, 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. EPA,
Cincinnati, Ohio.
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Appendix A
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Date: 11/86
Page 1 of 2
APPENDIX A
CLEANING OF PLASTICWARE
A-1.0 SAMPLE CONTAINERS
A laboratory supplies clean plastic sample containers (cubitainers,
Nalgene bottles, centrifuge tubes) to the field stations. The containers
are composed of amber, high-density linear polyethylene, and are of the
wide-mouth design. Each stream sample requires one 4-L cubitainer, one
500-mL capacity bottle, two 250-mL capacity bottles, three 125-mL
capacity bottles, one 50-mL graduated centrifuge tube with cap, and one
10-mL polypropylene test tube with cap. An equipment list is given in
Table 2.1
A-l.l Cleaning of Plasticware
Plasticware, in keeping with its use, is cleaned by either an acid
leaching procedure or water leaching procedure. Each is described
below.
A-l.1.1 Cleaning Procedure 1 (Acid Leaching)
All plasticware (with the exceptions in the next paragraph) is rinsed
three times with deionized water, three times with 3N HNO? (prepared
from Baker Instra-Analyzed HNO^ or equivalent), and six times with
deionized water. It is then filled with deionized water and is allowed
to stand for 48 hours. Next, it is emptied, is dried in a laminar-flow
hood delivering Class 100 air (when dry containers are necessary), and
is placed in clean plastic bags (bottles are capped first).
A-l.l.2 Cleaning Procedure 2 (DI Water Leaching)
Plasticware to be used for pH, BNC, ANC, and anion determinations is
rinsed three times with deionized water, is filled with deionized
water, is allowed to stand for 48 hours, and is then emptied and
sealed in clean plastic bags.
A-1.1.3 Quality Control
After the initial cleaning, 5 percent of the containers are checked to
ensure that rinsing has been adequate. The check is made by first
adding 500 mL (or maximum amount) deionized water to a clean con-
tainer, sealing the container with a cap or parafilm, and slowly
rotating it so that the water touches all surfaces. The specific
conductance of the water is then measured. It must be less than 1
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Appendix A
Revision 2
Date: 11/86
Page 2 of 2
MS/cm. If any of the containers fail the check, all of the containers
are rerinsed, and 5 percent are retested.
NOTE: The deionized water used in cleaning the plasticware must meet or
exceed specifications for ASTM Type I reagent grade Water.
-------
LAB NAME
BATCH ID
NATIONAL SURFACE HATER SURVEY
FORM 11
SUMMARY OF SAMPLE RESULTS
LAB MANAGER'S SIGNATURE
Page 1 of 2
SAM-
PLE
ID:
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
ALIQUOT ID
1
Ca
mg/L
Hg
mg/L
K
ng/L
Na
ng/L
Mn
mg/L
Fe
mg/L
2
Extr.
Al
mg/L
3
C1
mg/L
SO,
mg/L
mg/L
S10?
mg/L
ISE
Total F
mg/L
CD
tO
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n>
NOTE: Approved Data Qualifiers and instructions for their use are listed in Table 3.10.
NSWS Form 11
(/) 3
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-------
LAB NAME
BATCH ID
NATIONAL SURFACE WATER SURVEY
FORM 11
SUMMARY OF SAMPLE RESULTS
LAB MANAGER'S SIGNATURE
Page 2 of 2
SAM-
PLE
ID:
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
ALIQUOT 10
4
DOC
mg/L
NH,
mg/L
5
Measured
Eq.
PH
ANC
Inlt. pH
BNC
Inlt. PH
'
BNC
ueq/L
ANC
ueq/L
COND.
liS/cm
Eq.
DIC
mg/L
Inlt.
DIC
mg/L
6
Total
P
mg/L
7
Total
A1
mg/L
NOTE: Approved Data Qualifiers and Instructions for their use are listed In Table 3.10.
NSWS Form 11 (Continued)
O 50 J>
(U 0> TD
c* < T3
n> * CD
«/> 3
- Q.
o ->
oo
co
-------
Appendix B
Revision 2
Date: 11/86
Page 3 of 16
Lab Name
NATIONAL SURFACE WATER SURVEY
Form 13
ANC AND BNC RESULTS
Batch ID
Sample ID_
Lab Manager's Signature Analyst
]
I
I
(
(
]
RESULTS
~ANC] = ueg/L
)ATA
:* « eo/L
* = eq/L
DATE STANDARDIZED
DATE STANDARDIZED
NITIAL SAMPLE VOLUME
ACID
VOLUME HC1
(mL)
0.00
0.00 (with KC1)
TITRATION
MEASURED
PH'
CALCULATED
PH
mL
BLANK ANC
BASE TITRATION
VOLUME NaOH
(mL)
0.00
0.00 (with KC1)
MEASURED
PH'
CALCULATED
PH
NSWS Form 13
-------
NATIONAL SURFACE WATER SURVEY
Form 14*
QC DATA FOR ANC
AND BNC ANALYSES
Appendix B
Revision 2
Date: 11/86
Page 4 of 16
LAB NAME
BATCH ID
LAB MANAGER'S SIGNATURE
SAMPLE
ID
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
ANC
[jeq/L
C02-BNC
[jeq/L
CALCULATED ANC
RESULT
DIFFERENCE0
ZDb
*Form not required in data package but recommended for internal QC requirements.
Difference = Calculated ANC-Measured ANC
bRefer to Section 4.0.
NSWS Form 14*
-------
NATIONAL SURFACE HATER SURVEY
For* 15*
LAB NAME
CONDUCTIVITY
BATCH 10
LAB MANAGER'S SIGNATURE
Sample
ID
01
02
03
04
OS
06
07
OB
09
io
11
1Z
13
IT
^5^
IF
f J
18
19
Zd
Zl
22
23
Z4
Z5
Z6
27
ZH
Z9
30
SPECIFIC CONDUCTANCE
(uS/ci»)
Calculated
Measured
ID**
CAlCULflllD CONDUCTANCE FOR EACH ION pS/Cfl
HCOJ
Ca+2
co3-z
ci-
Hg*2
N03-
K*
Na*
S04'2
NH4*
H*
OH"
3.5XI03 1.9ZXIO
Specific Conductance Factors of Ions
t(pS/on at 25'C) per iiigA] 0.71S
2.60 2.82 2.14 3.82 1.15 1.84 2.13 1.54
(per (per
4.13 mole/I) mole/I)
* For* not required 1n data package but reconmended for Internal QC requirements
-o o TO y>
to o> n> ~o
ua «- < -o
m m -* n
.. Crt 3
tn -ex
o -
O I-1 3 X
** * Conductance Difference «
Calculated Cond.-Measured Cond.
x 100
ro oo
> OO
Measured Conductance
NSWS Form 15
-------
Appendix B
Revision 2
Date: 11/86
Page 6 of 16
LAB NAME
NATIONAL SURFACE HATER SURVEY
Form 16*
ANION-CATION BALANCE CALCULATION
BATCH ID LAB MANAGERS SIGNATURE
Sample
ID
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
X Ion
Difference **
Factor to Convert
mg/L to ueq/L
Ions - (ueq/L)
Ca+2
49.9
cr
28.2
Mq+2
82.3
N03~
16.1
K*
25.6
Na*
43.5
V
-
20.8
F-
52.6
NH>,*
55.4
ANC
H****
* Form not required 1n data package but recommended for Internal QC requirements
ANC -i- E Anions - £ Cations (except H+)
** % Ion Difference
*** [H+] = (10-P") x 106
Z Anions + E Cation + ANC + 2[H*]
x 100
NSWS Form 16
-------
Appendix B
Revision 2
Date: 11/86
Page 7 of 16
NATIONAL SURFACE WATER SURVEY
Form 17 Page 1 of 1
1C RESOLUTION TEST
LAB NAME
BATCH ID
LAB MANAGER'S SIGNATURE
1C Resolution Test
1C Make and Model:_
Date:
Concentration: S042~ ug/mL, N03 ug/mL
Column Back Pressure (at max. of stroke): psi
Flow Rate: mL/min
Column Model: Date of Purchase:
Column Manufacturer:
Column Serial No:
Is precolumn in system Yes No
(a) cm (b) cm
Percentage Resolution: 100 x (1-a/b)
The resolution must be greater than 60 percent
Test Chromatogram:
NSWS Form 17
-------
Appendix B
Revision 2
Date: 11/86
Page 8 of 16
LAB NAME
NATIONAL SURFACE WATER SURVEY
Form 18
QUALITY ASSURANCE
(DETECTION LIMITS)
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Units
Instrumental
Contract Required Detection Date Determined
Detection Limit Limit (DD MMM YY)
Ca mg/L
Mg mg/L
K mg/L
Na mg/L
Mn mg/L
Fe mg/L
Total Extr actable
Al mg/L
Cl mg/L
S04 mg/L
N03 mg/L
Si 02 mg/L
Total dissolved
F mg/L
NH4 mg/L
DOC mg/L
Specific
Conductance pS/cm
DIC mg/L
Total dissolved
P mg/L
Total Al mg/L
0.01
0.01
0.01
0.01
0.01
0.01
0.005
0.01
0.05
0.005
0.05
0,005
0.005
0.01
0.1
*
0.05
0.002
0.005
,
-
*Report the Y, which must not exceed 0.9 pS/cm, of six (6) nonconsecutive blanks.
Note 1: Indicate instrument for which IDL applies by using the following code
letters - F (furnace AA), P (ICP), L (Flame AA). Place the code
letter after the IDL value reported.
NSWS Form 18
-------
NATIONAL SURFACE MATER SURVEY
FORM 19
Page 1 of 2
LAB NAME
BATCH ID
SAMPLE HOLDING TIME SUMMARY
LAB MANAGER'S SIGNATURE
DATE* SAMPLED
DATE RECEIVED
Parameter
Holding
Tine
Holding Time
Plus
Date Sampled
Saaple ID:
01
02
03
04
05
06
07
08
09
10
11
12
13
14
IS
16
17
18
19
20
21
ZZ
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37 .
38
39
40
Ca
28
"9
28
K
28
Ma
28
Date*
Mn
28
Fe
28
Total
Extr. Al
7
Cl
28
so4
28
Analyzed**
NO
7
S102
28
I5E
Total r
28
-O O 73 J>
CD O> "O
to c+ < T3
to 3
-" O.
O -
3 X
1C
O
Report these dates as Julian dates (I.e.. March 26, 1984 4086).
**If parameter was reanalyzed because of QA probi ens, report the last date analyzed.
i1 oo
en cr>
. PO O3
NSWS Form 19
-------
LAB NAME
DATE* SAMPLED
NATIONAL SURFACE HATER SURVEY
FORM 19
SAMPLE HOLDING TINE SUMMARY
BATCH ID LAB MANAGER1S SIGNATURE
DATE RECEIVED
Page 2 of 2
Parameter
Holding
Time
Holding Time
Plus
Date Sampled
Sample ID:
01
oz
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
ZO
21
ZZ
23
24
25
Z6
Z7
29
Z9
30
31
3Z
33
34
35
36
37
38
39
40
DOC
14
NH4
28
Eq. pH
14 _,
BNC
14
AMC
14
Specific
Conductance
14
Eq. DIC
14
Inlt. DIC
14
Total P
28
Total Al
28
Date* Analyzed**
Report these dates as Julian dates (I.e.. March 26. 1984 4086).
**If parameter was reanalyzed because of QA problems, report the last date analyzed.
NSWS Form 19 (Continued)
-O O 30 J>
O> O» ft> T3
U3 <-» < -O
O>
in 3
I-. -.. O.
O O ->
K- 3 X
O I
-h ~-- ro CD
CD
!- CT>
-------
NATIONAL SURFACE WATER SURVEY
FORM 20
Page 1 of 2
LAB NAME
BATCH ID
BLANKS AND QCCS
LAB MANAGER'S SIGNATURE
Parameter
Calibration
Blank
Reagent Blank
DL (Theoretical
QCCS (Measured
Low QCCS
True Value
Low QCCS Upper
Control Limit
Low QCCS Lower
Control Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS Upper
Control Unit
High QCCS Lower
Control Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Final
ALIQUOT ID
1
Ca
mg/L
N
Mg
mg/L
N
K
mg/L
N
Na
mg/L
N
Mn
mg/L
N
Fe
mg/L
N
2
Total
Extr.Al
mg/L
N
3
Cl
mg/L
N
N
N
SOa
mg/L
N
N
N
NO?
mg/L
N
N
N
S102
mg/L
N
N
ISE
Total F
mg/L
N
N
N
Note: Approved Data Qualifiers and instruction for their use are listed in Table 3.10.
NSWS Form 20
-O O 73 3>
(U ft) CD "O
to rt- < -o
fo n - n>
«/) 3
!_ -i. Q.
(-* O -
!- 3 X
O H-"
-h-».ro DO
CO
>- 0»
cr>
-------
NATIONAL SURFACE WATER SURVEY
FORM 20
Page 2 of 2
LAB NAME
BATCH ID
BLANKS AND QCCS
LAB MANAGER'S SIGNATURE
Parameter
Calibration
Blank
Reagent Blank
DL theoretical
QCCS measured
Low QCCS
True Value
Low QCCS Upper
Control Limit
Low QCCS Lower
Control Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Final
High QCCS
True Value
High QCCS Upper
Control Limit
High QCCS Lower
Control Limit
Initial
Continuing
Continuing
Continuing
Continuing
Continuing
Final
4
DOC
mg/L
N
N
N
NH4
mg/L
N
N
N
ALIQUOT ID
Measured
Eq
pH
N
N
N
N
ANC
PH
N
N
N
N
BNC
PH
N
N
N
N
5
Cond.
uS/cm
N
N
N
Eq.
DIC
mg/L
N
N
N
Init.
DIC
mg/L
N
N
N
6
Total
P
mg/L
N
7
Total
Al
mg/L
Note: Approved Data Qualifiers and Instruction for their use are listed in Table 3.10.
NSWS Form 20 (Continued)
-O O 70 3>
O> D» (0 T3
to c+ < -o
fl> fD
l/> =3
!_. - O.
ro o -
(-- 3 X
O t-1
-h --^ro oo
CO
-------
LAB HAKE
BATCH ID
NATIONAL SURFACE WATER SURVEY
FORM 21*
DILUTION FACTORS
LAB MANAGER'S SIGNATURE
Page 1 of 2
SAM-
PLE
ID:
01
02
03
04
05
06
07
08
09
in
11
1Z
13
14
1ft
16
17
18
19
20
ZI
22
23
Z4
25
26
Z7
28
29
30'
31
32
33
34
35
36
37
38
39
40
ALIQUOT ID
1
Ca
ng/L
"9
ng/L
K
»g/L
Na
ng/L
Mn
ng/L
Fe
ng/L
z
Total
Extr. A1
ng/L
3
Cl
mg/L
S04
ng/L
K0?
ng/L
S102
g/C
ISE
Total f
mg/L
*Fomrnot required In the data package but recoaaended for QA purposes.
NOTE: Indicate samples ran on higher concentration range by using a check mark for each parameter.
NSWS Form 21
-O O 70 >
P> O» n> T3
U3 c+ < T3
(D (T) ' CT>
OJ O -"
t 3 X
O -'
-h ~^ ro CD
en
I-* CTl
-------
NATIONAL SURFACE HATER SURVEY
FORM 21*
Page 2 of 2
LAB NAME
BATCH 10
DILUTIONS FACTORS
LAB MANAGER'S SIGNATURE
SAM-
PLE
ID:
01
OZ
03
04
OS
06
01
08
09
ID
11
12
13
14
IS
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
ALIQUOT ID
4
DOC
mg/L
NH4
mg/L
5
Measufe'3
Eq.
PH
ANC
In1t. pH
BNC
Inlt. pH
CO;
BNC
peq/L
ANC
peq/L
COND.
pS/crn
Eq.
DIC
mg/L
imt.
DIC
mg/L
6
Total
P
mg/L
7
Total
Al
mg/L
Form not required In the data package but recommended for QA purposes.
NflTE: Indicate samples ran on higher concentration range by using a check mark for each parameter.
NSWS Form 21 (Continued)
-o o 73 :>
Q> O> ft) T3
(D ' fD
t/> 3
!_. _J. Q-
*» O -
»- =J X
O I-1
-h- r\> DO
CX5
h^ CTi
-------
NATIONAL SUFACE WATER SURVEY
Form 22
Page 1 of I
DUPLICATES
LAB NAME
BATCH ID
LAB MANAGER'S SIGNATURE
Parameter
Duplicate
Sample ID
Sample Result
Duplicate
Result
% RSD
Second Duplicate
Sample ID
Sample Result
Duplicate
Result
% RSD
Third Duplicate
Sanple ID
Sample Result
Duplicate
Result
% RSD
ALIQUOT ID
1
Ca
mg/L
Mg
mg/L
K
mg/L
Na
mg/L
Mn
mg/L
Fe
mg/L
2
Total
Extr.Al
mg/L
3
Cl
mg/L
SO,
mg/L
NO?
mg/L
S10?
mg/L
ISE
Total F
mg/L
Note: Approved Data Qualifiers and Instructions for their use are listed 1n Table 3.10.
NSWS Form 22
-O O 33 3»
O> 0> fl> "O
tn ft < T3
n> rt> '
l/> 3
!_ -4. CX
VI O -
!- 3 X
CO
ro oo
cn
-------
LAB NAME
NATIONAL SURFACE WATER SURVEY
Form 22
DUPLICATES^
BATCH ID
Page 2 of 2
LAB MANAGER'S SIGNATURE
Parameter
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*
ALIQUOT ID
4
DOC
mg/L
NH4
mg/L
Measured
Eq.
PH
ANC
Initial
PH
BNC
Initial
PH
5
C02
BNC
ueq/L
ANC
ueq/L
Cond.
uS/cm
Eq.
DIC
mg/L
Init.
DIC
mg/L
6
Total
P
mg/L
7
Total
A1
mg/L
"O O 30 3>
O» O> CO T3
to r+ < -o
*Report absolute difference rather than RSD for pH determinations.
Note: Approved Data Qualifiers and Instructions for their use are listed in 3.10.
NSWS Form 22 (Continued)
cn
O I-1
oo
in 3
_1. Q.
o -
X
ro CD
-------
Appendix C
Revision 2
Date: 11/86
Page 1 of 24
APPENDIX C
EXAMPLES OF CALCULATIONS REQUIRED FOR
ANC AND BNC DETERMINATIONS
C-1.0 HC1 STANDARDIZATION (SECTION 4.8.1)
1.00 mL of a 0.01038N Na2C03 plus 40.00 mL C02~free deionized water
is titrated with HC1 titrant. The titration data are given below.
mL HC1
added p_H
0.00 10.23
0.100 9.83
0.200 9.70
0.300 9.54
0.400 9.28
0.500 8.65
0.600 7.20
0.700 6.71
is calculated for the data sets (V, pH) with pH 4-7 by using the
equation
V,C / [HT]K! + 2 K, K2 \ KW
mL HC1
added
0.800
0.900
1.000
1.100
1.200
1.300
1.400
1.500
PH
6.37
6.03
5.59
4.91
4.48
4.26
4.11
4.00
mL HC1
added
1.700
1.900
2.100
2.300
2.500
PH
3.84
3.72
3.63
3.56
3.49
lb s (vs + v) \[H+]2 + [H*]^ + K! K2
where
Vs = initial sample volume = 41.0 mL
V = volume of HC1 added.
C = 1.266 x 10"4 = (N Na2C03)/(2 x 41)
.., = 4.4463 x lO'J,
Ko = 4.6881 x 10'11
C, = 1.01 x 10'14
-------
Appendix C
Revision 2
Date: 11/86
Page 2 of 24
The (V, Fj^) values are tabulated below.
V Flb (x 10"3) V Flb (x 10"3)
0.700 3.57 1.100 -0.34
0.800 2.59 1.200 -1.33
0.900 1.60 1.300 -2.28
1.000 0.64 1.400 -3.26
1.500 -4.23
The plot of Flb versus V is shown in Figure C-l. The data lie on a
straight line and are analyzed by linear regression to obtain the coeffi
cients of the line:
Flb = a + bV
from the regression,
r = 1.0000
a = 0.01038 ± 0.00001
b = -0.009747 ± 0.000012
Then V]^ = -a/b = 1.065 ml
and
N Na2C03 V0 (0.01038) (1.00)
Nun = - = - - = 0.009743 eq/L
HU V 1.065
vo
-------
Appendix C
Revision 2
Date: 11/86
Page 3 of 24
-5J
Figure C-l. Plot of F^ versus V for HC1 standardization.
-------
Appendix C
Revision 2
Date: 11/86
Page 4 of 24
C-2.0 NaOH STANDARDIZATION (SECTION 4.8.2)
C-2.1 Initial NaOH Standardization with KHP (Section 4.8.2.1)
5.00 ml of 9.793 x 10~4 N KHP plus 20.0 ml COp-free deionized water
are titrated with approximately 0.01N NaOH. The titration data and
appropriate Gran function values are given in the table below.
Volume NaOH
(ml) pH F3b(x 10'3)
0.000 4.59
0.050 4.78
0.100 4.97 3.90
0.150 5.14 3.39
0.200 5.31 2.86
0.250 5.48 2.34
0.300 5.66 1.82
0.350 5.87 1.29
0.400 6.14 0.79
0.450 6.66 0.26
0.500 8.99 -0.25
0.700 9.95 -2.29
0.900 10.23 -4.40
1.100 10.39
1.300 10.51
The Gran function F3b is calculated for data with pH 5-10. F3b is
culated by
F3b = (V + Vs)
vs c ([H]K + 2[H]) KW
(Vs + V)
V = Volume NaOH added
Vs = Initial sample volume = 25.00 mL
C = N KHP/5 = 1.9586 x 10'4
[H+] = 10-PH
K, = 1.3 x 10~3
Ko = 3.9 x 10'6
Kw = 1.01 x 10"14
versus V is plotted in Figure C-2. The data lie on a straight line
i the equation F3 = a + bV. The coefficients are calculated by using
linear regression. From the regression,
r = 1.0000
a = 0.004931 ± 0.000008
b = -0.01036 ± 0.00002
-------
Appendix C
Revision 2
Date: 11/86
Page 5 of 24
Figure C-2. Plot of F^b versus V for initial NaOH standardization with KHP,
-------
Appendix C
Revision 2
Date: 11/86
Page 6 of 24
From this Y3 and N^gH are calculated by
V3 = -a/b = 0.4761 ml
NKHP x VKHP
NNaOH = = 0.01028 eq/L
V3
C-2.2 Standardization Check (Section 4.8.2.2)
0.500 ml of 0.00921N NaOH plus 25.0 ml C02-free deionized water is
titrated with 0.0101N HC1 (standardized with Na^O^). The titration
data and appropriate Gran function values are given in the table below.
Volume HC1
(ml) pH F, (x 10~3)
0.000 10.29
0.100 10.15
0.200 10.03 2.75
0.250 9.91 2.09
0.300 9.78 1.55
0.350 9.60 1.03
0.400 9.34 0.57
0.450 8.39 0.064
0.500 4.76 -0.45
0.550 4.44 -0.94
0.600 4.26 -1.43
0.650 4.12 -1.98
0.700 4.04 -2.39
0.800 3.88
The Gran function Fj is determined for data in the pH range 4-10. Fj is
calculated by:
F, = (V + Vc) [ - [H+]
c =
[H*J =
= volume of HC1 added
= initial sample volume = 25.5 ml
10-PH
Kw = 1.0 x 10~14
Fi versus V is plotted in Figure C-3. The data are on a straight line
with the equation Fj = a + bV. The coefficients, determined by linear
regression, are
r = 0.9994
a = 0.00465 ± 0.00005
b = -0.01016 ± 0.0001
-------
Appendix C
Revision 2
Date: 11/86
Page 7 of 24
2-
1-
co
b
-1
2
-3 J
0.2 0.4 \ 0.6 0.8
V
Figure C-3. Plot of Fi versus V for standardization check-titration
of NaOH with HC1.
-------
Appendix C
Revision 2
Date: 11/86
Page 8 of 24
From these values, Vj^ and NHC-| are calculated by
YX = -a/b = 0.4577
NNaOH x vNaOH
NHC1 = - = 0.01006
Comparing this value for N^ci with the previously determined value of
» "the % difference is
% difference in N values =
0.01006 - 0.0101
x 100 = 0.4%
0.0101
This % difference is acceptable since it is less than 5%.
C-2.3 Routine NaOH Standardization with Standardized HC1 (Section 4.8.2.3)
1.000 ml of an approximately 0.01N NaOH solution plus 25.00 ml of CO?-
free deionized water is titrated with 0.009830N HC1. The titration data
are given below.
ml HC1
added pH
1.200 3.78
1.400 3.62
ml HC1
added
0.00
0.200
0.400
0.600
0.650
0.700
pH
10.44
10.30
10.13
9.71
9.51
9.19
ml HC1
added
0.750
0.800
0.850
0.900
1.000
1.100
pH
5.35
4.65
4.37
4.22
4.02
3.88
Fj is calculated for each data pair (V, pH) with a pH 4-10 by using the
equation
Fl
where
Vs = initial sample volume = 26.00 ml
V = volume of HC1 added.
[H+] = 10-PH
Kw = 1.0 x 10"14
The new data pairs (V, Fj) are tabulated below.
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Appendix C
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Date: 11/86
Page 9 of 24
(x 10~3) V Fi (x 10"3)
0.400 3.56 0.850 -1.14
0.600 1.36 0.900 -1.62
0.650 0.86 1.000 -2.58
0.700 0.41 1.100 -3.57
0.750 -0.12
0.800 -0.60
A plot of Fi versus V is shown in Figure C-4. The data sets corresponding
to volumes from V = 0.40 to V = 1.10 lie on a straight line with the
equation
F! = a + bV
The coefficients are obtained by linear regression. The results are
r = 0.9996
a = 0.007488 ± 0.00008
b = -0.0101 ± 0.0001
From these results,
Y! = -a/b = 0.741
NHC1 x vl (0.009830) (0.741)
VNaOH 1-000
= 0-00728
-------
4 -,
3 -
2 -
1 -
CO
I
O
-1 -
-2 -
-3 -
.4 J
0.4
0.6
Appendix C
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Page 10 of 24
Figure C-4. Plot of ?i versus V for routine NaOH standardization.
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Appendix C
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Page 11 of 24
C-3.0 ELECTRODE CALIBRATION (SECTION 4.8.3)
This section describes the electrode calibration procedure. The tables
below (A and B) tabulate both the titration data (V and pH), the calcu-
lated pH values (pH*), and the coefficients for the line pH = a + b pH*,
TABLE A. ACID TITRATION
Vs = 50.50
Volume HC1
(mL)
0.000
0.025
0.050
0.100
0.150
0.200
0.250
0.300
0.350
0.400
mL 1
PH
5.87
5.25
4.97
4.68
4.51
4.38
4.29
4.22
4.15
4.10
YHC1 = 0.00983
pH*
___
5.31
5.01
4.71
4.54
4.41
4.31
4.24
4.17
4.11
Volume HC1
(mL)
0.450
0.500
0.600
0.800
1.000
1.200
1.500
1.700
2.000
PH
4.05
4.00
3.92
3.80
3.71
3.64
3.55
3.50
3.43
pH*
4.06
4.02
3.94
3.81
3.72
3.64
3.55
3.50
3.43
r = 1.00 a = 0.10 ± 0.01 b = 0.971 ± 0.002
TABLE B. BASE TITRATION
Vs = 40.4
Volume HC1
(mL)
0.000
0.050
0.200
0.300
0.400
0.500
0.600
mL NNa0n = 0.00804
PH
6.66
9.03
9.55
9.66
9.75
9.90
10.00
pH*
9.00
9.60
9.77
9.90
9.99
10.07
Volume HC1
(mL)
0.820
0.940
1.080
1.200
1.300
1.400
1.500
PH
10.18
10.25
10.31
10.36
10.40
10.43
10.47
pH*
10.20
10.26
10.32
10.37
10.40
10.43
10.46
r = 0.99 a = 0.08 ± 0.27 b = 0.99 ± 0.03
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Appendix C
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Page 12 of 24
The data in Tables A and B are plotted in Figure C-5. Except for two
points in the base titration (at V = 0.3 and 0.4), the data lie on a
straight line. (The lines calculated for each titration are essentially
coincident as indicated by their coefficients.) Excluding these two
points, the data are fit to the line with the equation pH = a + b pH*.
The coefficients of the line (obtained by linear regression) are
r = 1.0000
a = -0.014 ± 0.0011
b = 0.999 ± 0.002
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Appendix C
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Page 13 of 24
x
CL
pH'
Figure C-5. Plot of pH versus pH* for electrode calibration.
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Appendix C
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Page 14 of 24
C-4.0 BLANK ANALYSIS - ANC DETERMINATION (SECTION 4.9.2)
This section describes the determination of ANC in a blank solution.
The blank is prepared by adding 0.40 mL of 0.10M Nad to 40.00 mL
deionized water. It is titrated with 0.00983N HC1. The titration data
are given below (both measured and calculated pH* values are included).
Volume HC1
(mL)
0.000
0.080
0.120
0.200
0.300
0.400
PH
5.84
4.69
4.52
4.31
4.14
4.01
pH* Fj
5.85
4.70
4.53
4.32 0.00194
4.14 0.00295
4.02 0.00390
Volume HC1
(mL)
0.500
0.600
1.700
1.000
1.200
1.500
PH
3.91
3.84
3.77
3.62
3.55
3.45
pH*
3.91
3.84
3.77
3.62
3.55
3.45
Fl
0.00503
0.00593
0.00698
0.00993
0.0117
0.0149
The Gran function i
less than 4.5, and th
= (Vs + V) [HT]) is calculated for pH* value
e values are included in the table.
Fi versus V is plotted in Figure C-6. The data are linear and fit the
line FI = a + bV by using linear regression. The resulting coefficients
are:
r = 0.9998
a = (-0.70 ± 5.6) x 10~5
b = 0.00989 ± 0.00007
From this,
Vj = -a/b = 7.05 x 10"4 mL
r , ViCHCl
[ANC] =
V0 = blank volume = 40.4 mL
This value for [ANC] is acceptable.
= 1.7 x ID'7 = 0.17 ueq/L
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Appendix C
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Page 15 of 24
0.4 0.6 0.8 1.0 1.2 1.4
Figure C-6. Plot of Fj versus V for ANC determination of blank.
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Appendix C
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Page 16 of 24
C-5.0 SAMPLE ANALYSIS
C-5.1 Titration Data
A sample was titrated as described in section 4.10. The titration data
are given below. Also included are values for the calculated pH (pH*).
Acid Titration
Vsa = 40.00 mL
= 0.00983 eq/L
i PH
Base Titration
Vsb = 40.00 mL
Cb = 0.00702 eq/L
Vb PH
Vsalt - °-40 mL
pH* \
vsalt = °-40 mL
PH* Vb
PH
PH
pH*
0.000
0.040
0.080
0.120
0.140
0.160
0.260
0.280
0.380
5.10
4.89
4.71
4.56
4.50
4.44
4.24
4.21
4.08
5.11
4.90
4.72
4.57
4.51
4.44
4.24
4.21
4.08
0.460
0.550
0.650
0.750
0.900
1.100
1.400
1.700
3.99
3.91
3.84
3.77
3.69
3.61
3.50
3.42
3.99
3.91
3.84
3.77
3.69
3.61
3.50
3.42
pH*
0.00
0.015
0.030
0.050
0.080
0.120
0.160
0.200
0.240
0.280
0.320
0.340
0.360
5.08
5.13
5.26
5.35
5.57
5.78
6.06
6.30
6.65
6.98
7.29
7.46
7.62
5.09
5.14
5.27
5.36
5.58
5.79
6.07
6.31
6.66
7.00
7.31
7.48
7.64
0.425
0.470
0.500
0.540
0.560
0.600
0.660
0.700
0.780
0.900
1.000
1.100
1.405
8.30
8.66
8.85
9.01
9.10
9.21
9.35
9.44
9.57
9.72
9.83
9.92
10.12
8.32
8.68
8.87
9.03
9.12
9.23
9.37
9.47
9.60
9.75
9.86
9.95
10.15
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Appendix C
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Page 17 of 24
PH
pH*
PH
pH*
0
0
.380
.400
Initial
7
8
.83
.03
Estimate of V
7
8
j (
.85
.05
Section
1
2
2
4.11.1)
.700
.200
.500
10
10
10
.26
.43
.51
10
10
10
.29
.43
.54
The Gran function Fja is calculated for each data pair from the acid
titration with a pH* <4. The values are given in the table below.
Va
0.460
0.550
0.650
0.750
Fla(xlO-3)*
4.18
5.04
5.93
6.99
va
0.900
1.100
1.400
1.700
Fla(xl(T3)*
8.43
10.2
13.2
16.0
*F1a = (V. + V.) [H+]
la as
versus Va is plotted in Figure C-7. A regression of F^a on Va is
performed to fit the data to the line Fja = a + bV. The resulting
coefficients are:
r = 0.9999
a = -0.00014 ± 0.000031
b = 0.00948 ± 0.000038
From this, the initial estimate of Vj is calculated by
Vj = -a/b = 0.0148 ml
Since Vj >0 and the initial sample pH* <7.6, calculation procedure B
(Section 4.11.3) is used to determine tTTe ANC and BNC of the sample.
C-5.3 Initial Estimates of V9> ANC, BNC, and C (Section 4.11.3.1)
From the base titration data, V£ is estimated to be 0.40 ml (the first
point with a pH* <8.2). Now that initial estimates of Vi and ^2 nave
been obtained, esTimates of ANC, BNC, and C can be calculated.
Vl C
c
= 3.6 x 10~6 eq/L
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Appendix C
Revision 2
Date: 11/86
Page 18 of 24
16-
14-
12-
«? 10-
o
T-
_»<
CD
6-
4-
- 2-
0.2 0.4 0.6 0.8 1.0 1.2
Va
1.4 1.6 1.8
Figure C-7. Plot of Fja versus Va for initial
determination of Vj.
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Appendix C
Revision 2
Date: 11/86
Page 19 of 24
= 7.02 x 10-5 eq/L
s
C = ANC + BNC = 7.38 x 1Q-5 eq/L
C-5.4 Refined Estimates of Vi and V?
The Gran function Flc (Equation 1 in 4.11.1.3) is calculated for acid
titration data with volumes across the current estimate of Vj. The
values are given below.
F(xl(T4)
lc
F(xlO-4)
lc
0.000
0.040
0.080
0.120
0.140
-1.68
-4.10
-7.05
-10.4
-12.1
0.160
0.260
0.280
0.380
-14.4
-23.2
-24.9
-33.8
Flc versus Va is plotted in Figure C-8.
performed. The regression results are
r = 0.999
a = -0.00006 ± 0.00003
b = -0.00864 ± 0.00016
A regression of
on Va is
A new estimate of Vj is
Vj = -a/b = -0.007 ml
Next the Gran function F?c (Equation 2, section 4.11.1.3) is calculated
from data sets from the base titration with volumes across the current
estimate of ^2- The values are given below.
For(x 10~4)
F?r(x 10'4)
2c
0.340
0.360
0.380
0.400
0.425
1.99
1.28
.555
-0.031
-.868
0.470
0.500
0.540
0.560
0.600
-2.60
-4.14
-6.03
-7.43
-9.55
-------
Va
Appendix C
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Date: 11/86
Page 20 of 24
0.04 0 0.04
0.12 0.20 0.28 0.36 0.44
i i i I i i i i I
-5-
-10-
-15-
-20'
-25-
-30-
-35-
Figure C-8. Plot of FIC versus Va for YI determination.
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Appendix C
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Page 21 of 24
versus V|) is plotted in Figure C-9. A regression of ?2c on vb 1S
performed. (Data with Vb >0.5 are not used in the regression.) The
regression results are
r = 0.999
a = 0.00138 ± 0.00003
b = -0.00348 ± 0.00007
A new estimate of V2 1S
V2 = -a/b = 0.397 mL
C-5.5 New Estimates of ANC, BNC, and C
From the new estimates of Vj and V£, new estimates of ANC, BNC, and C
are calculated.
Vi Ca
ANC* = = -1.7 x lO'6 eq/L
Vsa
V2 Cb
BNC* = = 6.97 x ID'5 eq/L
Vsb
C* = ANC + BNC = 6.80 x 10"5 eq/L
C-5.6 Comparison of Latest Two Estimates of Total Carbonate
C - C*
C + C*
Since C and C* do not agree, a new C is calculated from their average:
C(new) = (C + C*)/2 = 7.09 x 10'5 eq/L
The calculations in 5.4 and 5.6 are repeated until successive iterations
yield total carbonate values which meet the above criteria. The results
from each iteration (including those already given) are given below.
= 0.041 >0.001
ANC BNC C
Iteration V^mL) V?(mL) (ueq/L) (ueq/L) (ueq/L)
1
2
3
4
5
0.0148
-0.007
-0.0070
-0.0076
-0.0077
0.400
0.397
0.397
0.397
0.396
3.6
-1.7
rl.7
-1.9
-1.9
70.2
69.7
69.7
69.7
69.5
73.8
68.0
68.0
67.8
67.6
C - C*
C + C*
0.042
0.021
0.012
0.007
New C
(ueq/D
_
70.9
69.4
68.6
-
The final values for ANC and BNC are reported on Form 11.
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Appendix C
Revision 2
Date: 11/86
Page 22 of 24
«
1
o
^
o
eg
u.
3-i
2-
1-
0-
-1-
-2-
-3-
-4-
-5-
-6-
-7-
-8-
-9-
1 n.
*V Vb
0.30 \0.40 0.50 0.60 0.70
_xrx i ^ i i i
X
Figure C-9. Plot of F2c versus Vjj for V2 determination.
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Appendix C
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Date: 11/86
Page 23 of 24
C-6.0 QUALITY CONTROL CALCULATIONS
Examples of the QC calculations are described in this section.
C-6.1 Comparison of Calculated ANC and Measured ANC (Section 4.9.6)
For the sample analyzed in section C-5, the following data were
obtained.
initial pH = 5.09 air-equilibrated pH = 5.06
DIC = 0.59 mg/L air-equilibrated DIC = 0.36
From these data, the calculated ANC values are computed by using the
equation:
[ANC]C =
DIC [H]K! + 2Kj K2 \ KW
- [H+] x 106
.12011
The results are:
[ANC] C1 = -5.7 ueq/L [ANC]C2 = -7.3 ueq/L
Then:
|[ANC]C1 - [ANC]C2| = 1.6 Meq/L <15 ueq/L
Since [ANC]ci and [ANC]c2 are *n agreement, their average value is used
for comparison to the measured value.
[ANC]c.avg = -6.5 ueq/L ANC = -1.9 ueq/L
D = |ANCC - ANC| = 4.6 peq/L <15 peq/L
The calculated and measured ANC values agree, and this backs up the
assumption of a carbonate system.
C-6.2 Comparison of Calculated and Measured BNC (Section 4.9.7)
For the sample analyzed in section C-5, the following data were
obtained.
initial pH = 5.09
DIC = 0.59 mg/L
BNC = 69.0 ueq/L
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Appendix C
Revision 2
Date: 11/86
Page 24 of 24
From these data, the BNC is computed by using the equation:
' DIC / [H+]2 - K, K2 \ Kw
[BNCL = L * * ril+n W
[12011 \CH+] + CF
The result is:
[BNC]C = 54.8 ueq/L
This value is compared to the measured value.
D = [BNC]C - BNC = -14.2 ueq/L < -10 ueq/L
Although borderline, this value of D is indicative of other protolytes
in the system which are contributing to the measured BNC. This might be
expected since the sample also contains 3.2 mg/L DOC.
C-6.3 Comparison of Calculated Total Carbonate and Measured Total Carbonate
(Section 4.9.8)
For the sample analyzed in section C-5, the following data were
obtained.
initial pH = 5.09 BNC = 69.0 ueq/L = 69.0 umole/L
DIC = 0.59 mg/L ANC = -1.9 ueq/L = -1.9 umole/L
From the DIC value, the total carbonate is calculated.
Cc = 83.26 x DIC = 49.1 umole/L
This calculated value is then compared to the measured value.
D = Cc - (ANC + BNC) = -18.0 umole/L < -10 umole/L
Although borderline, this value of D is indicative of other protolytes
in the system. This might be expected since the sample also contains
3.2 mg/L DOC. Notice that the same conclusion was reached in the BNC
comparison.
In general, noncarbonate protolytes are significant (i.e., contribute
significantly to the total protolyte concentration) when they are
indicated by one (or both) of the individual comparisons (ANC and BNC
comparisons) and the total carbonate comparison.
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