Fast screening of the working condition effects in potentiometry with ion-selective electrodes

Summary

The effects of chemcial interferences and instrumental parameters on the analytical signal of three ionselective electrodes for nitrate, chloride and cyanide have been studied. The evaluation of the effects is performed by the economic design of Plackett-Burman which enables an easy and fast screening of many variables. It is shown that the electrode behaviour differs, depending on its function in the linear or non-linear part of the calibration curve. Very significant effects prove to be the state of the electrode membrane and the presence of some chemical interferences. Other influences, such as stirring rate or response time, do not affect the electrode function significantly. The estimation of the working condition effects makes it possible to perform complex analytical procedures more easily.