General notes
GB
Guidelines for photometric measurements
1. Vials and caps should be cleaned thoroughly after each analysis to prevent interference.
2. The outside of the vial must be clean and dry before starting the analysis. Clean the outside
of the vials with a towel to remove fingerprints or other marks.
3. Zero calibration and test must be carried out with the same vial as there may be slight
differences in optical performance between vials.
4. The vials must be positioned in the sample chamber for zeroing and test with the
on the vial aligned with the
5. Always perform zeroing and test with the vial cap tightly closed. Only use the cap with
a sealing ring.
6. Bubbles on the inside wall of the vial lead to incorrect measurements. To prevent this,
remove the bubbles by swirling the vial before performing the test.
7. Avoid spillage of water into the sample chamber because this can lead to incorrect test
results.
8. Contamination of the transparent cell chamber can result in wrong readings. Check at
regular intervals and – if necessary – clean the transparent cell chamber using a moist
cloth or cotton buds.
9. Large temperature differences between the instrument and the environment can lead
to errors – e.g. due to the formation of condensation in the cell chamber or on the vial.
10. To avoid errors caused by stray light do not use the instrument in bright sunlight.
11. Prior to measurement ensure that the sample is suitable for analysis (no major interference)
and does not require any preparation i.e. pH adjustment, filtration etc.
Correct position of the vial (Ø 24 mm):
Correct filling of the vial:
MD100_7c 03/2020
mark on the instrument.
mark
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