Hach POCKET COLORIMETER II, Instruction Manuals

Page: 47 / 116

1—47
Chlorine, Free and Total, HR,
continued
Manganese,
Oxidized
(Mn
4+
, Mn
7+
) or
Chromium,
Oxidized (Cr
6+
)
1.
Adjust sample pH to 6–7.
2.
Add 3 drops Potassium Iodide (30-g/L) (Cat. No. 343-32)
to a 5-mL sample.
3.
Mix and wait one minute.
4.
Add 3 drops Sodium Arsenite (5-g/L) (Cat. No. 1047-32)
and mix.
5.
Analyze 5 mL of the treated sample as described in
the procedure.
6.
Subtract the result from this test from the original analysis
to obtain the correct chlorine concentration.
Interfering
Substance
Interference Levels and Treatments