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The instructions listed below should be carefully followed during testing to ensure best accuracy.
• For adding the exact amount of sample and reagent to the cuvette it is recommended to use
three class A laboratory pipettes.
• Alternatively, fill the cuvette up to the 10 mL mark: 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.
• In order to measure exactly 0.5 mL of reagent with the 1 mL syringe:
(a) push the plunger completely into the syringe and insert the tip into the solution.
(b) pull the plunger up until the lower edge of the seal is exactly on the 0.0 mL mark.
(c) take out the syringe and clean the outside of the syringe tip. Be sure that no drops are
hanging on the tip of the syringe, if so eliminate them. Then, keeping the syringe in vertical
position above the cuvette, push the plunger down into the syringe until the lower edge of
the seal is exactly on the 0.5 mL mark. Now the exact amount of 0.5 mL has been added
to the cuvette, even if the tip still contains some solution.
GENERAL TIPS FOR AN ACCURA
TE MEASUREMENT
class A pipette
• Color or suspended matter in large amounts may cause interference, therefore these should be
removed by treatment with active carbon and by prior filtration.
• 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.
