Thermo Fisher Scientific C101 Colorimeter - Manual (Page 43)

Calibration
C401/301/201/101/102/103/104/105 Colorimeter
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3 CALIBRATION
The C401/301/201/101/102/103/104/105 Colorimeter was calibrated and
tested prior to leaving the factory. Therefore, it is possible for you to use
the instrument directly out of the box. Re-calibration of the instrument is
NOT recommended particularly in the case of chemical tests of very
unstable and/or difficult to prepare calibration solutions. However, the
meter allows you to calibrate in one point for each chemical test fitted in
the instrument. It is recommended to calibrate the pH at 7.0 pH units using
the supplied colorless 7.0 pH buffer.
For each of the chemical tests fitted in the instrument, the Colorimeter
requires only one standard solution for a complete calibration. During
calibration, the instrument performs several system self-diagnostics. As
such, several warning messages will be displayed. If the instrument
detects an irregularity with either the detector or the lamp, a warning
message will be displayed during or upon exiting the calibration mode. If
this occurs, attempt to rectify the situation as indicated in Section 4
Troubleshooting Guide.
In any event, the instrument will continue to read
the concentration or pH, but with a decreased accuracy until the error is
rectified.
The meter has an auto exit feature whereby it will exits the calibration
mode if no key is pressed within 10 minutes or if there is an error during
calibration.
3.1 Calibration Procedure
The standard calibration solutions are to be prepared in the ranges
indicated in the specifications. Standard solutions should be measured
accurately and qualified by a different method or another instrument of
higher precision and accuracy.
NOTE: Do not pour liquid directly into the sample well of the instrument.
Always use a vial. The instrument will only accurately measure the sample
when vials sealed with the black caps are used. The black cap serves as
both seal and a light shield.
NOTE: Do not attempt to clean the sample well. The optics may be
damaged.
NOTE: This instrument is designed to measure solutions contained in the
custom made glass vials and therefore the use of other type of sample vials
or sample cells may result in inaccurate measurements.