Facile Synthesis of Iminodiacetate-Stabilized Gold Nanoparticles with Sensitive Detection of CrIII.

A highly sensitive, selective, and quick colorimetric assay for Cr^III detection has been developed by using iminodiacetate (IDA) modified gold nanoparticles (AuNPs). These AuNPs were prepared by a hydrothermal method with IDA as both a reductant and a stabilizer. The as-prepared IDA-AuNPs display good selectivity for colorimetric detection of Cr^III in aqueous solution over 15 other metal ions. In the presence of an increasing amount of Cr^III, the color of the IDA-AuNPs changes gradually from red to blue, together with a redshift of the plasmon absorption, within 1 min. The detection limit of Cr^III was approximately 1.5 µM for the naked eye and 0.3 µM for UV/Vis spectroscopy. A good linear relationship was obtained between the logarithm of the ratios (A₆₅₀/A₅₂₀) and the concentration of Cr^III over the range 0.3-3 µM. The feasibility of this technique was evaluated for the successful detection of Cr^III in drinking-water samples, with good recoveries. [ABSTRACT FROM AUTHOR]