Avoiding Errors In Photometric Measurements - Millipore Spectroquant Multy Operating Manual

4.3 Avoiding errors in
photometric measurements
1. The cells and lid must be cleaned thoroughly after each analy-
sis run to prevent errors due to cross-contamination. Even
the smallest residues of reagents will lead to erroneous results.
2. The outer walls of the cells must be clean and dry before the
analysis is carried out. Fingerprints or water droplets on the
light-path surfaces of the cells will lead to erroneous results.
3. The cells for the zero calibration and the test itself must always
be inserted into the measurement compartment in such a way
that the white triangle or, respectively, the line of the graduation
is correctly aligned with the corresponding mark on the case
(see page 16 or 17).
4. The zero calibration and the test itself must both be made with
the cell lid in place. The cell lid of the 24-mm cell must be
fitted with a seal ring. The 16-mm cell must be covered with
the lid for the adapter.
5. The formation of air bubbles on the inner walls of the cell will
lead to erroneous results. In this case attach the cell lid to
the cell and swirl the cell to eliminate any air bubbles before
carrying out the test.
6. Care must be taken to prevent any water from entering the
measurement compartment. Any entry of water into the case
of the colorimeter may result in the destruction of electronic
components and in damage due to corrosion.
7. Any contamination of the optical components in the measure-
ment compartment will lead to erroneous results. The light-path
surfaces of the measurement compartment must be checked
at regular intervals and cleaned wherever necessary. Use moist
wipes and cotton-wool buds for these cleaning operations.
8. Major differences in temperature between the colorimeter and
the local environment can lead to erroneous results, e.g. due to
condensation on the optical components and on the cell.
9. When operating the colorimeter make sure that it is protected
from direct sunlight.
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