Manual

Test Procedure
1 Filter sample if necessary to obtain a clear solution.
2 Using the measuring syringe take 1 ml of the sample. Transfer to the test tube
and make up to the 10 ml mark with deionised water.
3 Add one Nitriphot No 1 tablet, crush and mix to dissolve.
4 Add one Nitriphot No 2 tablet, crush and mix to dissolve. Cap immediately.
5 Stand for exactly two minutes to allow full color development. Ignore any
further color development after this time.
6 Select Phot 43 on the photometer.
7 Take photometer reading in the usual manner (see photometer instructions).
8 The result is displayed as mg/l NaNO
2
.
Interferences
Chlorine in excess of 30 mg/l may give slight positive interference. However,
nitrite and chlorine are incompatible and do not normally co-exist.
The solution should be cooled to below 30°C before testing for the most accurate
analytical results.
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