Organic Carbon, Total
Organic Carbon, Total
OrganicCarbonTotal_Other_High_DIR_Eng_Ody.fm Page 5 of 6
Method Performance
Precision
See Section 3.4.3 Precision on page 44 for more information, or if the standard
concentration did not fall within the specified range.
Sensitivity
See Section 3.4.5 Sensitivity on page 44 for more information.
To test for TOC levels below 100 mg/L C, use Method 10173. For more
information on determining precision data and method detection limits, refer to
Section 3.4 Method Performance on page 42.
Summary of Method
The total organic carbon (TOC) is determined by first sparging the sample under
slightly acidic conditions to remove the inorganic carbon. In the outside vial,
organic carbon in the sample is digested by persulfate and acid to form carbon
dioxide. During digestion, the carbon dioxide diffuses into a pH indicator
reagent in the inner ampule. The adsorption of carbon dioxide into the indicator
forms carbonic acid. Carbonic acid changes the pH of the indicator solution
which, in turn, changes the color. The amount of color change is related to the
original amount of carbon present in the sample. Test results are measured at 598
and 430 nm.
Program mg/L C 95% Confidence Limits of Distribution
426 100 ±14 mg/L C
426 250 ±13 mg/L C
426 400 ±15 mg/L C
426 550 ±23 mg/L C
426 700 ±34 mg/L C
Portion of Curve ∆Abs ∆Concentration
Mid-range 0.010 4 mg/L C
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