ORBECO SP600, Instruction Manual, Page: 27 / 334

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SP600 Spectrophotometer 01/2008
1.1 Methods
Notes:
1. The tablets must be added in the correct sequence.
2. The AMMONIA No. 1 tablet will only dissolve completely after the AMMONIA No. 2
tablet has been added.
3. The temperature of the sample is important for full colour development.
At a temperature below 20°C the reaction period is 15 minutes.
4. Sea water samples:
Ammonia conditioning reagent is required when testing sea water or brackish water
samples to prevent precipitations of salts.
Fill the test tube with the sample to the 10 ml mark and add one level spoonful of
Conditioning Powder. Mix to dissolve, then continue as described in the test
instructions.
5. Conversion:
mg/l NH
4
= mg/l N x 1.29
mg/l NH
3
= mg/l N x 1.22
6. N
NH
4
NH
3