DR/2400
Phosphorus, Acid Hydrolyzable Digestion
PhosphorusAcidHydro_Other_AD_Eng_Ody.fm Page 1 of 4
• Rinse all glassware with 1:1 hydrochloric acid. Rinse again with deionized water.
• The results of the reactive phosphorus test after the digestion will include the orthophosphate and the acid-hydrolyzable
(condensed) phosphate. The condensed phosphate concentration is determined by subtracting the result of an orthophosphate
test from this result. Make sure that both results are in the same units, either mg/L PO
4
3–
or mg/L P before subtracting. The result
from this test is subtracted from the result of a total phosphorus test to determine organic phosphorus.
• For field applications, use a Heatab Cookit Stove (Cat. No. 2206-00) in place of the hot plate.
Phosphorus,
Acid Hydrolyzable Digestion
(Method 8180
Acid Digestion Method*
*Adapted from Standard Methods for the Examination of Water and Wastewater 4500-P B & E
Scope and Application: For water, wastewater, and seawater; USEPA Accepted for wastewater analyses
1. Use a graduated
cylinder to measure
25 mL of sample. Pour
the sample into a 125-mL
Erlenmeyer flask.
2. Use a 1-mL calibrated
dropper to add 2.0 mL of
5.25 N Sulfuric Acid
Solution to the flask.
3. Place the flask on a
hot plate. Boil gently for
30 minutes.
Do not boil dry.
Concentrate the sample to
less than 20 mL for best
recovery. After
concentration, maintain
the volume near 20 mL by
adding small amounts of
deionized water. Do not
exceed 20 mL.
4. Cool the sample to
room temperature.
Tips and Techniques
Powder Pillows Method 8180
HRS MIN SECHRS MIN SEC
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