Selective colorimetric detection of Cr(VI) using starch-stabilized silver nanoparticles and application for chromium speciation

The selective quantitation of Cr(VI) was developed through colorimetric detection using starch-stabilized silver nanoparticles (starch-AgNPs). The detection of Cr(VI) was based on oxidative degradation of starchAgNPs as the reduction of UV-Vis signal and the distinctive color change from yellow to colorless of starch-AgNPs were observed. To achieve the highest sensitivity by this method, pH 3, and only 1 min were required for the determination of Cr(VI). For analytical performances, two linear ranges of 0- 6 mM and 10-80 mM with limit of detection of 0.93 mM (48 mg/L) and 11.57 mM (0.60 mg/L) were obtained, respectively. The developed colorimetric method was combined with inductively coupled plasma optical emission spectroscopy (ICP-OES) for the speciation analysis of chromium. The concentration of Cr(III) was calculated by subtraction of Cr(VI) from the total chromium concentration determined by ICP-OES. A satisfactory accuracy and precision based on the AOAC guidelines also proved that this simple and rapid sensor was successfully applied for speciation of chromium in real water samples.(c) 2022 Elsevier B.V. All rights reserved.