Metrohm 900 Touch Control Manual - Manual (Page 416)

29.11 Electrode test for pH electrodes (ELT)
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400 ￭￭￭￭￭￭￭￭
900 Touch Control
NOTE
Ensure in particular the flawlessness of the pH 9 buffer. It can readily
deviate from its specified pH value as the result of absorption of CO
2
from the ambient atmosphere, thus leading to incorrect test results.
Stirrer
A stirrer has to be connected for the electrode test.
Temperature
Take care to ensure that the entire electrode test is carried out at a consis-
tently uniform temperature. Work should be accomplished at room tem-
perature wherever possible, in light of the fact that temperature exercises
a great influence on response time. The preset limit values are calibrated
to 25 °C.
29.11.1 Electrode test parameters
Under [Electrode test param.], the parameters influencing the
sequence of the electrode test are defined.
Buffer type
Selecting a predefined buffer series.
Selection Metrohm | NIST | DIN | Fluka Basel | Mettler |
Merck Tit. | Radiometer | Merck Cer. | Baker |
Hamilton | Precisa
Default value Metrohm
Merck Cer.
Reference temperature = 25 °C. When using Merck CertiPUR buffers
(20 °C) the buffer type Merck Tit. must be selected.
Sample Processor
If the calibration is carried out with a Sample Processor, the buffers or
standards are automatically changed. This is why no request for the cali-
bration temperature appears when starting the calibration. The value
entered above is used.
Selection off | Remote | USB
Default value off
off
For calibrations without Sample Processor. During the calibration, a
request for changing the buffer/standard is displayed.