Mecaptosuccinic acid modified gold nanoparticles as colorimetric sensor for fast detection and simultaneous identification of Cr3

Abstract In this paper, for the first time, we used mecaptosuccinic acid (MSA) modified gold nanoparticles to detect Cr 3+ selectively. The procession is indicated by a red shift of the UV–vis absorption and a dramatic color change from red to blue. Under optimized conditions, this technique exhibits high selectivity to Cr 3+ over other tested heavy metal ions. The ratio between the absorbance wavelength at 650 nm and 520 nm (A 650 /A 520 ) is linearly proportional to the concentration of Cr 3+ in the range from 0.6 to 1.4 μM. The detection limit is estimated as low as 0.04 μM by UV–vis spectroscopy and 0.6 μM by naked eyes, respectively, making naked eye-detection of Cr 3+ feasible. This result is below the maximum accepted levels of chromium in drinking water (0.962 μM) by the World Health Organization. This simple approach is tried to detect trace Cr 3+ in real water samples and shows recoveries of 93–107%. The overall sensing assay is simple, cheap (by the use of MSA) and fast (the detection time is 10 mins). Therefore, it has the potential application to be the on-site, real-time and low-cost Cr 3+ sensor.