Metrological parameters of sulphur dioxide amperometric sensor containing addition of aprotic solvents

The paper presents the results of investigation on influence of aprotic solvents contained in an internal electrolyte on metrological parameters of a prototype of sulphur dioxide sensor with Nafion membrane. Five sensors differing in composition of the internal electrolyte have been compared. Gold electrode vacuum sublimation deposited on the Nafion membrane surface was a working electrode. The electrolytes were aqueous solutions of sulphuric acid of the summary concentration 5 mol dm−3 (electrolyte A). The electrolyte B contained an addition of dimethylsulphoxide (DMSO), the electrolyte C contained an addition of N,N-dimethylformamide (DMF), the electrolyte D contained an addition of acetonitrile (AC) and the electrolyte E contained an addition of propylene carbonate (PC); water/solvent molar ratio in these solutions was 2:1. Based on a proposed equation an influence of the analyte flow rate on the sensor signal and response time to changes of SO2 concentration was investigated.