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

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.