A polymeric membrane electrode for the detection of perchlorate in water at the sub-micro-molar level

Abstract

A highly sensitive polymeric membrane electrode was synthesized for the detection of perchlorate in water. The membranes were characterized for thickness, potentiometric responses, and response time. Factors such as interfering anions, humic acid, and pH that may affect the performance of the electrode were investigated. The membrane electrode exhibited favorable selectivity toward perchlorate over interfering anions such as chloride, nitrate, sulfate, and bicarbonate in water and had a response time of ca. 5 s over the perchlorate concentration (activity) range of 10⁻⁶ to 10⁻¹ M and a Nernstian slope of 58.5 ± 0.4 mV at room temperature. The potentiometric response of the electrode was pH independent in the range of 3.0 to 11.0 and had a perchlorate detection limit of 7.0 × 10⁻⁷ M (or 70 ppb). The polymeric membrane electrode was able to detect perchlorate ion at the sub-micro-molar level under conditions mimicking those of natural water systems.