BUCHI KjelSampler K-377 User Manual
Page 122
7 Maintenance
122
K-375/376/377 Operation Manual, Version B
We recommend replacing the electrode, if it does not fulfill the following criteria at 25 °C room
temperature anymore:
• Slope
95 – 105 %
• Zero point pH
6.4 – 7.6
For pH electrodes other than the ones supplied by BUCHI, additional criteria might be important.
NOTE
It is recommended to use buffer solutions pH 4.00 and 7.00.
Discard buffer solutions after usage. Work with fresh solutions every day.
To calibrate the pH electrode
• select System Preparation Calibration pH
electrode
• adapt all parameters to your needs
• press
START and follow the SOP given by
the software.
Details about all available parameters can be
found in chapter “6.6.1 System preparation”.
7 .1 .4
Filling boric acid into receiving vessel after last sample of rack was determined
By default the pH electrode has to be stored in saturated KCl solution. Keeping the electrode for a
long time in air reduces its lifetime.
If there is no chance to clean the electrode and store it in KCl solution, we recommend to fill boric
acid into the titration vessel after the last sample was determined.
Boric acid can be dosed into the receiver at the end of each sequence: