pH-isfet used as a detector in a flow injection titration system

Abstract

Ion-sensitive field effect transistors (ISFETs) have been successfully introduced into a titration system for flow injection analysis (FIA). The influence of the titration parameters of the ISFET-FIA system is discussed and experimentally studied. Various kinds of acid-base titration have been tested. There exists a good linearity between t_eq (titration time) and log C⁰₂ (concentration of analysed substance), with a regression coefficient better than 0.9997. The titration can be done at a rate of up to 75 samples per hour. The reverse titration method can extend the detection limit down to 5 × 10⁻⁴ M of the analysed substance.