Ag/AgCl reference electrode based on thin film of arabic gum membrane

Abstract

The Ag/AgCl reference electrode based on the Arabic Gum (AG) hydrogel films was successfully developed. The Arabic Gum concentration used in this study was 10–40% (w/v) with an optimum concentration of 20% (w/v). In this study, reference electrode performance testing is based on ΔmV response of Cl– ion measurements, stability tests and performance testing against ISE sensors such as K+, NH4+, and NO3–. The Ag/AgCl based reference electrode of the Arabic Gum film shows an average ΔmV of 4.0 ± 0.7 mV when response test is performed against a standard Ag/AgCl double junction electrode in various concentrations of Cl– ion. Meanwhile, instability testing conducted in a 0.01 M KCl solution for 72 h found drift of < 0.6 mV/h. The reference performance test of the Arabic Gum reference electrode with three types of ISE NH4+, K+, and NO3– commercial sensors obtaining a slope closer to the Nernst value is 54.9 ± 0.9, 52.3 ± 0.5 and-53.2 ± 0.2 mV/dec with all having a linear range of 0.1–10–5 M.