Graphite screen printed electrodes for the electrochemical sensing of chromium(VI)

We demonstrate that graphite screen printed macroelectrodes allow the low ppb sensing of chromium(VI) in aqueous solutions over the range 100 to 1000 microg L(-1) with a limit of detection of 19 microg L(-1). The underlying electrochemical mechanism is explored indicating an indirect process involving surface oxygenated species. The drawbacks of using hydrochloric acid as a model solution to evaluate the electrochemical detection of chromium(VI) are also pointed out. The analytical protocol is shown to be applicable for the sensing of chromium(VI) in canal water samples at levels set by the World Health Organisation. The protocol is simplified over existing analytical methodologies and given its analytical performance and economical nature, holds promise for the de-centralised screening of chromium(VI).