A Novel All-Solid-State Ion-Selective Electrode with Selenite-doped Polyaniline

A novel all-solid-state selenite electrode with Ag and nano-Ag as a substrate and selenite-doped polyaniline as a sensitive membrane was fabricated by using electrochemical methods. Nano-Ag particles were electrodeposited on the surface of a cathode Ag wire in 0.1 M AgNO 3 standard solution with a 1.2 V amplitude, 50 Hz frequency and 30 s action time. The polyaniline layer was coated by chronoamperometry and doped with selenite in selenite solution by the same technique. Scanning electron microscopy (SEM) and energy-dispersive spectroscopy (EDS) analysis proved the successful doping of selenite. The selenite electrode, which had excellent stability and repeatability, had an excellent Nernst linear response (slope -30.08 mV per decade, R 2 >0.99) with a linear range of 5×10 -6 ~1×10 -1 M and detection limit of 1.627×10 -6 M. The response time was less than 2 s, and the lifespan was more than 178 days. The electrode showed a high selectivity to selenite ions during the interference study. The recovery rates in the sample test were from 95~99%, indicating that the electrode can be applied in real sample measurements. Compared to previous work, this electrode is superior in terms of multiple properties.