Rapid colorimetric detection of arsenic (III) by glutathione functionalized gold nanoparticles based on RGB extracting system

A sensitive and selective method for the colorimetric detection of arsenic (As III ) ions has been demonstrated using glutathione functionalized gold nanoparticles (GSH-AuNPs). When arsenic ions are added to the GSH-AuNPs solution, the binding of arsenic ions with GSH ligands induces the aggregation of AuNPs, resulting in a rapid color change of the solution. With the implementation of a home-developed RGB extracting software, excellent linear correlation has been established between the calculated RGB color values and the arsenic concentrations ( R 2  = 0.99488). The limit of detection (LOD) of arsenic ions is as low as 0.12 ppb. More significantly, the GSH-AuNPs solution shows excellent detection selectivity to other metal ions (Fe 3+ , Co 2+ , Ni 2+ , K + , Na + , Mg 2+ , Ca 2+ , Cu 2+ , Hg 2+ , and Pb 2+ ). This method could be applied to on-site and real-time fast detection of low level arsenic ions.