Colorimetric detection of chromium(III) using O-phospho-l-serine dithiocarbamic acid functionalized gold nanoparticles

A sensitive and selective colorimetric Cr3+ detection method was developed by using O-phospho-l-serine dithiocarbamic acid (PSDTC) functionalized gold nanoparticles (PSDTC-AuNPs). The presence of Cr3+ immediately induced aggregation of PSDTC-AuNPs, yielding a color change from red to blue. This Cr3+-induced aggregation of PSDTC-AuNPs was monitored by bare eye and UV-vis spectroscopy. The SPR absorbance (651 nm) of the reaction between PSDTC-AuNPs and Cr3+ shows a good linearity in the Cr3+ concentration with a low detection limit 4.2 nM (S/N = 3). PSDTC-AuNPs showed excellent selectivity toward Cr3+ compared to other metal ions Ag+, Al3+, Ca2+, Cd2+, Co2+, Cu2+, Fe2+, Fe3+, Hg2+, Mg2+, Mn2+, Ni2+, Pb2+, and Zn2+. Optimal detection of Cr3+ was achieved over a pH range from 5 to 10. In addition, PSDTC-AuNPs were applied to detect Cr3+ in lake water, showing low interference.