Question

Which of the following is not a problem of ion selective electrodes?

(a) Interference with other ions

(b) Output is influences by ionic strength

(c) Drift in electrode potential during a sequence of measurements

(d) Can measure only positive ions

The question was asked during an interview for a job.

This intriguing question comes from Ion Selective Electrodes-Principle and Types in division pH Meters and Ion Analysers of Analytical Instrumentation

Answer 1

Right choice is (d) Can measure only positive ions

To explain: Ion selective electrodes can measure both positive and negative ions. It is affected by interference from other ions.