Phosphorus, Acid Hydrolyzable Hydrolysis To Orthophosphate Method - Hach DR/850 Procedures Manual

PHOSPHORUS, ACID HYDROLYZABLE
Hydrolysis to Orthophosphate Method
1.
Measure 25 mL of
sample into a 50-mL
erlenmeyer flask using a
graduated cylinder.
Note: Wash all glassware
with 6 N hydrochloric acid.
Rinse with deionized water.
Do not use detergents
containing phosphate to
clean glassware.
* Adapted from Standard Methods for the Examination of Water and Wastewater.
2.
Add 2.0 mL of
5.25 N Sulfuric Acid
Solution.
Note: Use the 1-mL
calibrated dropper
provided.
*
For water, wastewater, seawater
30:00
minutes
3.
Place the flask (the
prepared sample) on a
hot plate. Boil gently for
30 minutes.
Note: Samples should be
concentrated 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.
359
Method 8180
4.
Cool the hot
prepared sample to room
temperature.