Pulsed amperometric detection of sulfide, cyanide, iodide, thiosulfate, bromide and thiocyanate with microfabricated disposable silver working electrodes in ion chromatography

The authors introduce a new type of silver electrodes. The new electrodes are designed to be disposable and as such they are used only for a limited period of time, usually 5-7 days, and then discarded. Manual polishing, which is required with non-disposable electrodes, is not necessary with disposable electrodes. This manuscript describes the development of pulsed amperometric detection waveforms that make it possible to utilize disposable silver electrodes in the chromatographic detection of sulfide, cyanide, iodide, thiosulfate, bromide and thiocyanate. Also discussed is an evaluation of analytical performance of the electrodes with the newly developed waveforms. The detection limits were found to be 1 ppb (S2−), 2 ppb (CN−), 5 ppb (Br−, S2O32− and I−) and 10 ppb (SCN−) for a 10 μl injection volume. Calibration plots for S2−, CN−, Br− and S2O32− are linear from their respective detection limits up to 50-100 ppm. The linear calibration for I− and SCN− can be obtained from the detection limits up to 10 ppm. Reproducible long-term performance was confirmed in a 2-week experiment with 10 μl injections of 1 ppm CN−.