Hanna Instruments HI 93414 - Manual (Page 14)

14
GENERAL TIPS FOR AN ACCURATE MEASUREMENT
CUVETTE
The cuvette is part of the optical system in all measurements. The light reaches the sample by
passing through the cuvette glass. As a result, the measurement can be affected by the glass
imperfections, dirt, dust, scratches, or fingerprints present on the cuvette surface. So, special care
must be taken in preparing and handling the cuvette.
Note: In colorimetric measurements, when it is possible use the same cuvette both for zeroing and
measurement. If this is not possible always match the cuvettes.
Also, in turbidimetric measurements, if you are using multiple cuvettes, always match the cuvettes.
CUVETTE HANDLING
The cuvettes should be free of scratches or cracks. Any cuvette with visible scratches will be
discarded. The cuvettes should be periodically washed with acid. After washing, the cuvettes
should be well rinsed multiple times with distilled or deionized water. Allow cuvettes to air-dry
and store them for long periods of time with caps, to avoid dirt entering inside. Always handle
the cuvette by touching only the cap or its top side (over the horizontal line).
Always store the cuvettes in separate boxes or with separators between them to avoid scratches
on the surface.
CUVETTE PREPARATION
Whenever a cuvette is used, it must be clean inside and outside. When it is placed into the
instrument, it must be dry outside, completely free of fingerprints or dirt.
If the cuvette is not indexed, put the cuvette with the factory mark
aligned with the sign on the instrument top.
HI 93414 is a highly accurate combined meter for some very important drinking water parameters:
turbidity and free & total chlorine. To meet the instrument’s performance and fully benefit of its
features, it is very important for the analyst to use proper measurement techniques for accurate,
precise and repeatable readings. Special care must be taken during sample preparation and handling.
The instructions listed below should be carefully followed during measuring and calibration to ensure
best accuracy.