Hach DR/850 Procedures Manual page 383

PHOSPHORUS, TOTAL,
Method Performance
Interferences
continued
acid-washed 100-mL Class A volumetric flask. Dilute to the
mark with deionized water.
Precision
In a single laboratory, using a standard solution of 3.00 mg/L
PO 3- and two lots of reagent with the instrument, a single
4
operator obtained a standard deviation of ±0.06 mg/L PO
Estimated Detection Limit
The estimated detection limit for program 82 is 0.07 mg/L PO
For more information on the estimated detection limit,
see Section 1.
The following may interfere when present in concentrations
exceeding those listed below:
Substance
Aluminum
Arsenate
Chromium
Copper
Iron
Nickel
Silica
Silicate
Sulfide
Turbidity (large amounts)
Zinc
Highly buffered samples or
extreme sample pH
Store PhosVer 3 Reagent Powder Pillows in a cool,
dry environment.
383
Interference Level and Treatment
200 mg/L
Interferes at any level.
100 mg/L
10 mg/L
100 mg/L
300 mg/L
50 mg/L
10 mg/L
90 mg/L
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.
80 mg/L
May exceed the buffering capacity of the
reagents and require sample pretreatment; see
pH
Interferences (Section 1).
3- .
4
3- .
4