Interferences - Hach POCKET COLORIMETER II Instruction Manual

4. Analyze each standard addition sample as described in the procedure. The
phosphate concentration should increase 0.2 mg/L for each 0.1 mL of
standard added.
Standard Solution Method
Use a 3.00 mg/L phosphate standard solution in place of the sample. Perform the
procedure as described above.
Multi-parameter standards that simulate typical wastewater and drinking water
concentrations without dilution are available to confirm test results. See
Reagents on page
Standard Calibration Adjust Method
To perform a standard calibration adjustment using the 3.0 mg/L phosphate
standard, or using an alternative concentration, see
page 2—13

Interferences

Large amounts of turbidity may cause inconsistent results in the phosphate tests
because the acid present in the powder pillow may dissolve some of the suspended
particles and because of variable desorption of orthophosphate from the particles.
29.
Phosphorus, Reactive,
Standard Calibration Adjust on
1—25
continued
Optional