An All-Solid-State Ammonium Ion-Selective Electrode Based on Polyaniline as Transducer and Poly (o-phenylenediamine) as Sensitive Membrane

摘要

An all-solid-state ammonium ion-selective electrode, with silverano-silver wire as the substrate,polyaniline as transducer and poly (o-phenylenediamine) as sensitive membrane, is presented. Thenano-silver was prepared by electrodeposition in 0.1 M AgNO3 standard solution with the half-sinewave at amplitude of 500 mV, frequency of 50 HZ and action time of 1 min. The polyaniline and poly(o-phenylenediamine) were electropolymerized on the surface of the silverano-silver substrate bycyclic voltammetry with the scanning potential from 0 to 0.45 V in solutions of 1.0 M anilinehydrochloride and 0.08 M o-phenylenediamine hydrochloride, respectively. Under the SEM, poly (o- phenylenediamine) with 0.5-5 m in size was evenly and firmly embedded on the surface of the PANI.This ammonium electrode exhibited low impedance of approximately 70 Ohm. It can detect as low as-5 2 1.210 M of ammonium ion, with the slopes of 54.99-55.70 mV per decade (R >0.99) within a linear-5range between 210 M to 0.1 M. It responds as quickly as 0.5-2 s, as well as its lifespan extends to at+ least 147 days. The electrode showed a superior selectivity toward NH4 , and was successfully applied+ to detect the NH4 concentration in real samples. In addition, this electrode is miniature and convenient+ for package and assembly, which will enable in-situ measurement and long-term monitoring of NH4concentration in rivers, lakes and industrial sewage.