LaMotte SMART Spectro Spectrophotometer - Manual (Page 18)

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INTERFERENCES
LaMotte reagent systems are designed to minimize most common interferences.
Each individual test instruction discusses interferences unique to that test. Be
aware of possible interferences in the water being tested.
The reagent systems also contain buffers to adjust the water sample to the ideal
pH for the reaction. It is possible that the buffer capacity of the water sample
may exceed the buffer capacity of the reagent system and the ideal pH will not
be obtained. If this is suspected, measure the pH of a reacted distilled water
reagent blank using a pH meter. This is the ideal pH for the test. Measure the
pH of a reacted water sample using the pH meter. If the pH is significantly
different from the ideal value, the pH of the sample should be adjusted before
testing.
Chlorine interference can be removed with the use of glycine. Very high levels
of chloramines may interfere if the test result is not read immediately. Oxidized
manganese interferences but can be removed with arsenite. Bromine and iodine
interferes but can be removed with a thioacetamide blank correction.
Interferences due to high concentration of the substance being tested, can be
overcome by sample dilution (see page 16).
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STRAY LIGHT INTERFERENCE
Normal indoor lighting causes no interference with the SMART. Always be sure
the sample chamber lid is closed when scanning blanks or samples.
18 SMART SPECTRO SPECTROPHOTOMETER 05.04