ORBECO SP600, Instruction Manual, Page: 137 / 334

135
SP600 Spectrophotometer 01/2008
1.1 Methods
Notes:
1. Samples cannot be preserved and must be analysed immediately.
2. Sample temperature should be 21°C ± 4°C.
3. Caused by the reagent itself the blank may develop a faint yellow colour.
4. Interferences:
• Ammonium causes no interferences up to 10 mg/l.
At a concentration of 20 mg/l it is possible that the test result increase up to 20%.
• Morpholine does not interfere up to 10 mg/l.
• Highly colored or turbid samples:
Mix 1 part deionized water with 1 part household bleach. Add 1 drop of these
mixture into 25 ml of water sample and mix. Use 10 ml prepared sample in place of
deionized water in point 1.
Note: at point 7 use the unprepared water sample.
Principle: Hydrazine is oxidised by the household bleach. The interference by colour
will eliminated by zeroing.
5. There is an option to change the unit from mg/l to μg/l.
The unit mg/l is rounded, e.g.: 25 μg/l = 0.025 mg/l display 0.03 mg/l.
mg/l
μg/l