Highly sensitive chlorite ion sensor developed on the basis of etching of incurvate gold nanohexahedrons.

Incurvate gold nanohexahedrons (AuNHs) are feasible colorimetric probes for the monitoring of chlorite (ClO 2 −) ions. In this study, incurvate AuNHs were found to respond to ClO 2 − ions selectively, and the addition of ClO 2 − ions to water samples induced selectively the etching of incurvate AuNHs, eroding the sharp apexes to rounded edges, which brought in hypsochromic shift absorption attended by a color alternation from cobalt blue to violet pink. The process of etching of incurvate AuNH vertices was characterized using X-ray photoelectron spectroscopy and atom probe tomography. ClO 2 − ions were successfully detected using the incurvate AuNH-based probe at pH 2.0 and 25 °C with 20 mM NaCl. The A 563 nm /A 631 nm were linear in proportion to the ClO 2 − concentrations with two different slopes in the ranges 0.00–0.06 μM and 0.075–0.15 μM, and detection limits of 3.03 and 3.27 nM in tap water and waste water, respectively. The hypersensitive and selective optical assay reported herein has been excellently implemented to determine ClO 2 − concentrations in spiked tap water, waste water, Clorox cleaning solution, and disinfecting wipes. [Display omitted] • Incurvate AuNHs were synthesized as viable optical nanoprobe of ClO 2 − ions. • ClO 2 − ions induced selectively the etching for the sharp vertices of AuNHs. • The etching of AuNHs resulted in a color change from cobalt blue to violet pink. • The AuNH probe of ClO 2 − was optimized at pH 2, 25 °C, and 20 mM NaCl concentration. • The AuNH probe showed a LOD of 3.03 nM ClO 2 − in tap water. [ABSTRACT FROM AUTHOR]