What is meant by drift in ISE measurements?
Drift is the gradual change in electrode response over a period of time. The rate and extent of drift can vary depending on which particular ISE and reference electrodes are being used and the age and degree of contamination of the electrodes. If a series of samples are measured repeatedly it will be observed that each successive reading of the same solution will be slightly different from the previous one. This problem can be overcome by frequently measuring one calibration solution in between sample measurements, then re-calibrating when the mV value has drifted beyond an acceptable level – depending on precision requirements.
