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• Proper use of dropper:
(a) to get good reproducible results, tap the dropper on the table for several times and wipe
the outside of the dropper with a cloth.
(b) always keep the dropper bottle in a vertical position while dosing the reagent.
The instructions listed below should be carefully followed during testing to ensure best accuracy.
• Color or suspended matter in large amounts may cause
interference, therefore these should be removed by
treatment with active carbon and by prior filtration.
• For a correct filling of the cuvette: the liquid in the
cuvette forms a concavity on the top; the bottom of this
concavity must be at the same level of the 10 mL mark.
• Proper use of the powder reagent packet:
(a) use scissors to open the powder packet;
(b) push the edges of the packet to form a spout;
(c) pour out the content of the packet.
GENERAL TIPS FOR AN ACCURATE MEASUREMENT
(a)
(b)
• It is important that the sample does not contain any debris. This would corrupt the
reading.
• Each time the cuvette is used, the cap must be tightened to the same degree.