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Organic Carbon, Total
Sampling and Storage
Accuracy Check
Organic Carbon, Total
Page 4 of 6
Substance
Phosphate
Silica
Sulfate
Sulfide
Sulfite
Zinc
If the sample contains greater than 1000 mg/L CaCO
sample pH to less than 7 before testing by adding Sulfuric Acid Solution
(Cat. No. 2449-32).
Most sample turbidity is either dissolved during the digestion stage or settled
during the cooling period. Sample turbidities up to 900 NTU have been tested
without interference.
Collect samples in clean glass bottles. Rinse the sample bottle several times with
the sample to be collected. Fill the bottle completely full before capping. Test
samples as soon as possible. Acid preservation is not recommended.
Homogenize samples containing solids to assure representative samples.
Standard Additions Method (Sample Spike)
1. Prepare a 300-mg/L C standard as described in Standard Solutions Method,
below.
2. Use the TenSette pipet to add 0.1, 0.2, and 0.3 mL of the 300-mg/L C standard
to each of three Acid Digestion vials.
3. Add the contents of one TOC Persulfate powder pillow to each vial.
4. Add 0.3 mL sample to each vial. Swirl to mix.
5. Proceed with the procedure starting at step 8 on page 2.
6. The mg/L C concentration should increase by 100 mg/L for each 0.1 mL
increment.
See Section 3.2.2 Standard Additions on page 32 for more information.
Standard Solutions Method
1. Prepare a 1000-mg/L organic carbon stock standard by dissolving 2.1254 g
dry primary standard Potassium Acid Phthalate in Organic-Free Reagent
Water and dilute to 1000 mL. This stock standard is stable for about 1 month
at room temperature.
Alternatively, open one ampule of TOC Standard Solution
(Cat. No. 27915-05).
2. Prepare a 300-mg/L C standard by transferring 15.00 mL of the stock
standard to a 50-mL Class A volumetric flask. Dilute to volume using
Organic-Free Reagent Water. Stopper and mix thoroughly. Prepare this
standard fresh daily.
(continued)
Maximum Level Tested
3–
3390 mg/L PO
4
100 mg/L SiO
2
2–
5000 mg/L SO
4
2–
20 mg/L S
2–
50 mg/L SO
3
5 mg/L
alkalinity, lower the
3
OrganicCarbonTotal_Other_High_DIR_Eng_Ody.fm
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