Tetrabutylammonium-chloride-glycerol of deep eutectic solvent functionalized MnO2: a novel mimic enzyme for the quantitative and qualitative colorimetric detection of l-cysteine. Issue 1 (8th December 2022)

• Record Type: Journal Article
• Authors: Chen, Jing; Qin, Hangdao; Xu, Lu; Leng, Senlin; Chang, Jun
• Is Part Of: Analyst. Volume 148:Issue 1(2023)
• Page Start: 182
• Page End: 190
• Publication Date: 2022-12-08
• Subjects: Chemistry, Analytic -- Periodicals; 543
• DOI: 10.1039/d2an01771g
• Languages: English
• ISSNs: 0003-2654

Abstract

Abstract : Application of a novel colorimetric sensor based on a [N4444 ]Cl-G/MnO2 -TMB system for the quantitative and qualitative detection of l -cysteine. Abstract : l -Cysteine is a common amino acid that plays an important role in human livelihood and production. Therefore, a novel method for the simultaneous quantitative and qualitative determination of l -cysteine by a colorimetric detection system is proposed. As a viable oxidase mimic, [N4444 ]Cl-G/MnO2, which consisted of MnO2 nanosheets functionalized by a tetrabutylammonium chloride–glycerol ([N4444 ]Cl-G) based deep eutectic solvent (DES) was fabricated. Owing to the oxidation of MnO2 nanosheets, [N4444 ]Cl-G/MnO2 could oxidize the colorless 3, 3′, 5, 5′-tetramethylbenzidine (TMB) into a blue product (oxTMB) with the characteristic UV–vis spectrum absorbance at 652 nm. The oxidation of TMB by DES/MnO2 was inhibited when l -cysteine was introduced, and the absorbance decreased proportionally with the increase in l -cysteine concentration. Due to this inhibition effect, a colorimetric detection system ([N4444 ]Cl-G/MnO2 -TMB) was developed for the quantitative determination of l -cysteine. Under optimal conditions, the assay showed good linearity over the concentration range of 0.125–2.00 μg mL −1 with a low detection limit of 5.96 ng mL −1 . A study of the inhibition mechanism demonstrated that the sulfhydryl group of l -cysteine could decompose [N4444 ]Cl-G/MnO2 into Mn 2+, thus limiting the conversion of TMB to oxTMB. In addition, the [N4444 ]Cl-G/MnO2 -TMB system was used in test strips for the visual qualitative detection of l -cysteine. The selectivity and test strip results demonstrated the high selectivity, simple operation, and rapid response of the [N4444 ]Cl-G/MnO2 -TMB system for the qualitative detection of l -cysteine. Given the satisfying performance of the detection strategy, colorimetric sensing based on the [N4444 ]Cl-G/MnO2 -TMB system is considered to have prospective application value in the quantitative and qualitative detection of l -cysteine.