Hach DR/850, Procedures Manual, Page: 367 / 460

367
Interferences
The following may interfere when present in concentrations
exceeding these listed below:
The PhosVer 3 Phosphate Reagent Powder Pillows should be
stored in a cool, dry environment.
Sample Disposal Information
Final samples will contain molybdenum. In addition, final
samples will have a pH less than 2 and are considered corrosive
(D002) by the Federal RCRA.
Substance Interference Level and Treatment
Aluminum 200 mg/L
Arsenate Interferes at any level
Chromium 100 mg/L
Copper 10 mg/L
Iron 100 mg/L
Nickel 300 mg/L
Silica 50 mg/L
Silicate 10 mg/L
Sulfide 6 mg/L. Sulfide interference may be removed by
oxidation with Bromine Water as follows:
1. Measure 25 mL of sample into a 50-mL beaker.
2. Swirling constantly, add Bromine Water drop-wise
until a permanent yellow color develops.
3. Swirling constantly, add Phenol Solution dropwise
until the yellow color just disappears. Proceed with
step 1 .
Turbidity (large amounts) May cause inconsistent results because the acid present in
the powder pillows may dissolve some of the suspended
particles and because of variable desorption of
orthophosphate from the particles.
Zinc 80 mg/L
Highly buffered samples or
extreme sample pH May exceed the buffering capacity of the reagents and
require sample pretreatment; see pH Interferences
(Section 1).
PHOSPHORUS, REACTIVE,
continued