title: Selective colorimetric detection of Cr(iii) and Cr(vi) using gallic acid capped gold nanoparticles.
abstract: A colorimetric assay is proposed for the selective detection of Cr(iii) and Cr(vi) via the aggregation-induced color change of gallic acid capped gold nanoparticles (GA-AuNPs). The AuNPs are characterized using UV-vis spectroscopy, transmission electron microscopy (TEM), dynamic light scattering (DLS) and Fourier-transform infrared spectrometry (FT-IR). To detect Cr(iii) and Cr(vi) coexisting in a sample, citrate and thiosulfate were applied to mask Cr(vi) for the detection of Cr(iii), and ethylenediaminetetraacetic acid disodium salt (EDTA) was applied to mask Cr(iii) for the detection of Cr(vi). At optimized experimental conditions, the selectivity of these AuNPs-based detection systems is excellent for Cr(iii) and/or Cr(vi) compared with other types of metal ions. The limit of detections (LODs) of a mixture of Cr(iii) and Cr(vi), Cr(iii) and Cr(vi) by eye vision are 1.5, 1.5 and 2 μM, respectively, and those by UV-vis spectroscopy are 0.05, 0.1 and 0.1 μM, respectively. The minimum detectable concentrations for Cr(iii) or Cr(vi) are all below the guideline value set by the US Environmental Protection Agency (EPA). The applicability of the AuNPs-based colorimetric sensor is also validated by the detection of Cr(iii) and Cr(vi) in electroplating wastewater and real water samples with high recoveries.
authors.affiliation: School of Chemistry and Chemical Engineering, Anqing Normal College, Anqing, Anhui 246001, China. wugenh@aqtc.edu.cn.
authors.forename: Chen
authors.initials: C
authors.lastname: Dong
authors.forename: Genhua
authors.initials: G
authors.lastname: Wu
authors.forename: Zhuqing
authors.initials: Z
authors.lastname: Wang
authors.forename: Wenzhi
authors.initials: W
authors.lastname: Ren
authors.forename: Yujie
authors.initials: Y
authors.lastname: Zhang
authors.forename: Zheyu
authors.initials: Z
authors.lastname: Shen
authors.forename: Tianhua
authors.initials: T
authors.lastname: Li
authors.forename: Aiguo
authors.initials: A
authors.lastname: Wu