TOTAL ORGANIC CARBON (TOC) in SOIL
SW-846 Method 9060
Table 1. Summary of Contract Required. Detection Limits, Holding' Times, and
Preservation for Total Organic Carbon (TOC) in Soil
Analytical
Parameter
Contract
Required
Detection
Limit
(CRDL)
Technical and
Contract Holding
Times
Preservation
Total
Organic
Carbon (TOC)
200 mg/Kg
Technical: 28 days
from collection;
Contract: 26 days
from receipt at
laboratory
Cool to 4°C ±2°C;
protect from sunlight
and atmospheric oxygen
Homogenize samples by shaking, stirring, and/or pulverizing using a blender.
Using a separate portion of the sample, analyze for percent solids.
Remove inorganic carbon by the addition of several drops of 1:1 nitric acid to
a pH < 2. Dry samples in a drying oven to drive off C02. Allow 10 to 30
minutes drying time.
Analyze all samples in duplicate, including laboratory quality control samples
such as matrix spike and laboratory control samples (LCS). Report the average
value and relative percent difference.
The CRDL is 200 mg/Kg. Results should be reported down to the instrument
detection limit, if lower than the CRDL.
Data Calculations and Reporting Units:
Calculate the sample results according to Section 8 of SW-846 Method 9060.
Report sample results in concentration units of milligram per kilogram (mg/Kg)
of organic carbon on a dry weight basis. Calculate sample results according
to the following formula:
A = (B x 100,000) ^ (C x D)
Where A = concentration of TOC in mg/Kg (dry weight basis); B = TOC measured,
in /ig; C = Sample size, in mg; D = % Solids
Report organic carbon concentrations that are less than 10 mg/Kg to 2
significant figures, and organic carbon concentrations that are greater than
or equal to 10 mg/Kg to 3 significant figures.
For rounding results, adhere to the following rules:
a)	If the number following those to be retained is less than 5, round
down ;
b)	If the number following those to be retained is greater than 5,
round up; or
c)	If the number following the last digit to be retained is equal to
5, round down if the digit is even, or round up if the digit is
odd.
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All records of analysis and calculations must be legible and sufficient to
recalculate all sample concentrations and QC results. Include an example
calculation in the data package.
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Table 2. Summary of Calibration Procedures for Total Organic Carbon (TOC) by SW-846 Method. 9060
Calibration Element
Frequency
Acceptance
Criteria
Corrective Action
Initial Calibration
(minimum blank + 5
points) (ICAL)
Daily
r > 0.995
1.	Terminate analysis
2.	Recalibrate and verify before sample
analysis
Initial Calibration
Verification (ICV)
(Separate source from
ICAL standards)
Daily, prior to
sample analysis,
immediately following
ICAL
± 10% from
expected
concentration
1.	Reprep ICV and, reanalyze all
associated samples
2.	Identify and document problem
3.	Recalibrate and reanalyze reprepped
ICV and all associated samples, if
necessary
Continuing
Calibration
Verification (CCV) a
Before sample
analysis; after every
10 samples and end of
run
± 10% from
expected
concentration
1.	Recalibrate and verify
2.	Reanalyze samples back to last good
CCV
Calibration Blank
Verification (ICB,
CCB)
After ICV and CCVs
< CRDL
1.	Terminate analysis
2.	Identify and document the problem
3.	Recalibrate, verify and reanalyze all
associated samples
CRDL Verification
Standard (< 2X CRDL)
After initial CCV
± 20% from
expected
concentration
1.	Reprep and reanalyze standard
2.	Recalibrate and verify
aThe CCV must be at a different concentration than the ICV.
Dilute and reanalyze samples with TOC concentrations exceeding the range of the calibration curve. Results
for such reanalyses should fall within the mid-range of the calibration curve. Report results and submit
documentation for both analyses.
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Use between 10 and 50 mg of soil sample for analysis. Reanalyze using a smaller sample size if the TOC
concentration in a 10 mg sample exceeds the calibration range.
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Table 3. Summary of Internal Quality Control Procedures for Total Organic Carbon (TOC) by SW-846 Method.
9060
QC Element
Frequency
Acceptance
Criteria
Corrective Action
Method Blank
(MB)
One per Batch or SDG a
(1 per 20 samples
minimum)
< CRDL
1.	If lowest sample concentration is more than
10X the blank conc., no action
2.	If samples are non-detected, no action
3.	If detected sample concentrations are less
than 10X blank conc., all associated samples
must be prepared again with another method blank
and reanalyzed
Duplicate
Sample (DUP)
All samples in the
batch or SDG
RPD <20% for
samples >5X
CRDL; ± CRDL
for samples
<5X CRDL
1. Flag associated data with an
Matrix Spike
(MS)
One per batch or SDG
(1 per 20 samples
minimum)
± 25% from
expected
value b
1. Flag associated data with an "N"
Laboratory
Control Sample
(LCS)
One per batch or SDG
(1 per 20 samples
minimum)
± 20% from
expected
concentration
1.	Terminate analysis
2.	Identify and document the problem
3.	Reanalyze all associated samples
a SDG - Sample Delivery Group - each case of field samples received; or each 20 field samples within a case;
or each 14 calendar day period during which field samples in a case are received.
b An exception to this rule is granted in situations where the sample concentration exceeds the spike
concentration by a factor of 4. In such an event, the data shall be reported unflagged.
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Analyze all samples in duplicate, including MS, LCS, and blanks. Report the average and relative percent
difference of the results for duplicate analysis.
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