Highly sensitive detection of Cr(VI) by reduced graphene oxide chemiresistor and 1,4-dithiothreitol functionalized Au nanoparticles

Detection of highly toxic Cr(VI) is greatly desired. In the present study, a highly sensitive method for Cr(VI) detection by reduced graphene oxide (rGO) chemiresistor and 1,4-dithiothreitol (DTT) functionalized Au nanoparticles (AuNPs) is reported. The detection strategy is based on the selective binding between DTT functionalized AuNPs1 located in rGO conductive channels and DTT functionalized AuNPs2 in solution through the formation of disulfides induced by Cr(VI) at acidic condition, which results in aggregation of DTT functionalized AuNPs2 on the rGO channels producing a readily measurable resistance change. The response of the chemiresistor is rapid and allows real-time monitoring of Cr(VI). Using this method, as low as 0.9 nM of Cr(VI) in water was detected with good selectivity. The proposed method has great potentials for monitoring of trace Cr(VI) in drinking water.