Jin P, Tan W, Li X, Fan J, Li K. Methyl orange as a novel colorimetric iodide indicator with in situ generation of H2O2 by etching uncoated Ag-Ti3C2 nanohybrids.
Talanta 2023;
260:124619. [PMID:
37149939 DOI:
10.1016/j.talanta.2023.124619]
[Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Revised: 04/26/2023] [Accepted: 04/29/2023] [Indexed: 05/09/2023]
Abstract
Iodine intake remains a major public health concern, as both iodine excess and deficiency are related to adverse effects on health. Therefore, developing simple and economical methods to detect I- is still in great demand. Herein, we constructed a visual I- sensing platform based on the uncoated Ag-Ti3C2 nanohybrids using methyl orange (MO) as a colorimetric indicator. Plasmonic nanostructures are frequently employed in colorimetric analysis, but uncoated Ag nanoparticles (NPs) are unstable because their surface energies are usually high. Considering that Ag NPs can be etched by I- via forming Ag-I bond, we introduce Ag-Ti3C2 nanohybrids because uncoated Ag NPs with immaculate surfaces are more conducive to binding with I- and being etched. Dissolved O2 molecules adsorbed on Ti3+ of Ti3C2 MXenes enable the in situ generation of H2O2 by iodine-etching of uncoated Ag-Ti3C2 nanohybrids. ∙OH radicals promote the degradation of MO through a self-driven Fenton-like process, exhibiting the color variation from orange to transparent. Under optimal conditions, the absorbance of MO at 465 nm decreases linearly with the concentration of I- in the range of 0.5-300 μM, with a limit of detection as low as 0.31 μM. This work opens the feasibility of iodine-etching of Ag in developing novel probes for facile colorimetric determination of I-.
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