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 µ m for the naked eye and 0.3 µ m for UV/Vis spectroscopy. A good linear relationship was obtained between the logarithm of the ratios (A 650 /A 520 ) and the concentration of Cr III over the range 0.3–3 µ m . The feasibility of this technique was evaluated for the successful detection of Cr III in drinking‐water samples, with good recoveries.