Improved free chlorine amperometric sensor chip for drinking water applications

This paper outlines the advantages of using gold cathodes, in comparison to platinum ones, combined with a series of potential steps that keep the electrode active longer times. A working potential of 0.150 V versus Ag/AgCl (3 MKCl) allows the amperometric determination of free chlorine over the pH range most likely to be found in drinking waters. This pH window spans from pH 5 up to pH 8. The importance of pH and how it can influence the amperometric response inside and outside this narrow pH window is discussed.