Analysis of water in room temperature ionic liquids by linear sweep, differential pulse and square wave cathodic stripping voltammetries

In this work we put forward an optimized electroanalytical method for the determination of water in room temperature ionic liquids (RTILs) based on the reduction of a gold oxide layer prepared by chronoamperometry on gold electrodes under the presence of trace water. Linear sweep, differential pulse and square wave voltammetries were compared as stripping techniques, and the chronoamperometric growth of the gold oxide layer was studied and optimized, confirming the formation of up to three monolayers of AuO on the surface of the working electrode. For [C2mim][NTf2], dried for 12 h at 60 °C, concentrations of water of 110.5±4.6 ppm, a sensitivity of −ip,c/C = (10.9±0.4)×10−7 A ppm−1, a LOD = 3.3 ppm and a LOQ = 11.0 ppm were found using the proposed CSSWV method.