1.1 Methods
Notes:
1. Samples cannot be preserved and must be analysed immediately.
2. Sample temperature should be 21°C ± 4°C.
3. The blank may develop a faint yellow colour due to the reagent.
4. Interferences:
• Ammonia causes no interferences up to 10 mg/l.
At a concentration of 20 mg/l it is possible that the test result increases by 20%.
• Morpholine does not interfere up to 10 mg/l.
• Highly coloured or turbid samples:
Mix 1 part deionised water with 1 part household bleach. Add 1 drop of this
mixture into 25 ml water sample and mix. Use 10 ml prepared sample in place of
deionised water in point 1.
Note: at point 7 use the unprepared water sample.
Principle: Hydrazine is oxidised by household bleach. Colour interference will be
eliminated by zeroing.
5. There is an option to change the unit from mg/L to μg/L.
mg/l
μg/l
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