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Regeneration of the sensor is required when the function responds has dropped remarkably when calibration. This is caused by the depletion of electrolyte solution when the membrane is damaged or contaminated. To maintain the sensor, exchanging the electrolyte solution and membrane head and cleaning the electrodes are needed.
In general, electrode maintenance should only be necessary about once per year for steady-state polarographic sensors and about once every 3 months for steady-state galvanic sensors. Do not perform the following maintenance procedures just because a sensor ‘looks’ dirty. Only perform the following procedures if the instrument will not calibrate or if the readings are unstable and a regular membrane change did not correct either of these problems.
The following points should be emphasized when carrying out the cleaning and maintenance process. Source: http://www.eidusa.com/Theory_DO.htm#Cleaning of sensors
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