22
SECTION 2,
continued
2.2.2
Measurement Notes
•
Always cap the sample cell to prevent spillage of sample into
the instrument.
•
When taking a reading, place the instrument on a level, stationary
surface. It should not be held in the hand during measurement.
•
Always close the sample compartment lid during measurement
and storage.
•
Always use clean sample cells in good condition. Dirty, scratched,
or damaged cells can cause inaccurate readings.
•
Do not leave a sample cell in the cell compartment for extended
periods of time. This may compress the spring in the cell holder.
•
Remove sample cell and batteries from instrument if the instrument
is stored for extended time period (more than a month).
•
Avoid operating in direct sunlight.
•
Make certain cold samples do not “fog” the sample cell.
•
Avoid settling of sample prior to measurement.
•
Keep sample compartment lid closed to prevent dust and dirt
from entering.
2.3 Measurement Techniques
Proper measurement techniques are important in minimizing
the effects of instrument variation, stray light and air bubbles.
Regardless of the instrument used, measurements are more accurate,
precise and repeatable if the analyst pays close attention to proper
measurement techniques.
Measure samples immediately to prevent temperature changes and
settling. Avoid sample dilution when possible. Particles suspended in
the original sample may dissolve or otherwise change characteristics
when the sample temperature changes or when the sample is diluted,
resulting in a non-representative sample measurement.
