Solid Contact Potentiometric Sensors for Trace Level Measurements

Abstract

A simple procedure for the development of a range of polymeric ion-selective electrodes (ISEs) with low detection limits is presented. The electrodes were prepared by using a plasticizer-free methyl methacrylate−decyl methacrylate copolymer as membrane matrix and poly(3-octylthiophene) as intermediate layer deposited by solvent casting on gold sputtered copper electrodes as a solid inner contact. Five different electrodes were developed for Ag⁺, Pb²⁺, Ca²⁺, K⁺, and I^-, with detection limits mostly in the nanomolar range. In this work, the lowest detection limits reported thus far with solid contact ISEs for the detection of silver (2.0 × 10^-9 M), potassium (10^-7 M), and iodide (10^-8 M) are presented. The developed electrodes exhibited a good response time and excellent reproducibility.