Sampling And Storage; Accuracy Check - Hach POCKET COLORIMETER II Instruction Manual

Sampling and Storage

Collect samples in plastic or glass bottles that have been cleaned with
1:1 Hydrochloric Acid Solution and rinsed with deionized water. Do not use
commercial detergents containing phosphate for cleaning glassware used in
phosphate analysis.
Best results are obtained when samples are analyzed as soon as possible after
collection. If prompt analysis is impossible, preserve samples up to 48 hours by
storing at or below 4 °C. Warm to room temperature before testing.

Accuracy Check

Standard Additions Method
1. Using a graduated cylinder, measure the appropriate amount of sample from
Table 1 on page 1—40
2. Snap the neck off a Phosphate Voluette
50 mg/L PO
4
into each of three 50-mL volumetric flasks.
3-
.
Phosphonates,
®
Ampule Standard Solution,
1—47
continued