Liquid-membrane electrode sensitive to ammonia and aliphatic amines based on 1-[(2-oxyphenyl)iminomethly]-2-oxybenzene-O,O′,N-ammin-nickel(II) complex

In this study, an ammonia-gas-sensing liquid-state membrane electrode based on 1-[(2-oxyphenyl)iminomethyl]-2-oxybenzene-O,O′,N-ammin-nickel(II) (Ni(II)-Schiff base) as an ionophore was developed. This membrane electrode gave a very good performance and exhibited linear response with near-Nernstian slope of 50.7±0.5 mV per decade, within a concentration range of 1.0×10−1–1.0×10−3 M. The electrode performance depends on the pH of the test solution and the optimum pH range was 10.0–11.5. The effect of concentration of internal solutions in the electrode was also investigated. The selectivity properties of the electrode towards aliphatic amines at a pH value of 10.2 were investigated with the mixed-solution method. Furthermore, the response time and lifetime of the electrode prepared were determined.