Simultaneously colorimetric detection and effective removal of mercury ion based on facile preparation of novel and green enzyme mimic

• Published in: Spectrochimica acta. Part A, Molecular and biomolecular spectroscopy Vol. 266; p. 120410
• Main Authors: Zou, Yanyun, Chai, Qingli, Zhu, Ting, Yu, Xiaoxiao, Mao, Guobin, Li, Ningxing, Chen, Jinyang, Lai, Guosong
• Format: Journal Article
• Language: English
• Published: Elsevier B.V 05.02.2022
• Subjects: Chitosan; Colorimetric; Enzyme mimic; Hg2+ detection; Hg2+ removal; Enzyme mimic; Chitosan; Hg2+ removal; Hg2+ detection; Colorimetric
• ISSN: 1386-1425
• DOI: 10.1016/j.saa.2021.120410

[Display omitted] •A novel enzyme mimic was obtained through one-pot preparation of chitosan/Cu/Fe composite.•The enzyme mimic is environmentally-friendly, cost-effective and highly-efficient.•The enzyme mimic was applied in colorimetric detection of Hg2+ in a portable analytical tube.•Efficient Hg2+ removal could be realized at the same time of Hg2+ detection. In this work, an environmentally-friendly and cost-effective enzyme mimic was obtained by facile one-pot preparation of chitosan/Cu/Fe (CS/Cu/Fe) composite. This composite exhibited significantly enhanced oxidase-mimicking activity during catalyzing the oxidation of 3, 3′, 5, 5′-tetramethylbenzidine (TMB). The CS/Cu/Fe composite was comprehensively characterized and the possible catalytic mechanism was reasonably explored and discussed. Benefiting from the thermal stability and the compatibility with carbohydrate, the CS/Cu/Fe composite was further integrated with agarose hydrogel to fabricate a portable analytical tube containing oxidase mimic. Based on the inhibition of the catalytic oxidation of TMB in the presence of cysteine, as well as the recovery of oxidase-like activity of CS/Cu/Fe due to the specific complexation of cysteine and mercury ion (Hg2+), the rapid colorimetric detection of Hg2+ was successfully carried out in the analytical tube. This colorimetric method showed good linear response to Hg2+ over the range from 40 nM to 8.0 μM with a detection limit of 8.9 nM. The method also revealed high selectivity and satisfactory results in recovery experiments of Hg2+ detection in tap water and lake water. Furthermore, it was found that the effective removal of Hg2+ could be realized in the analytical tube based on efficient Hg2+ adsorption by CS/Cu/Fe composite and agarose hydrogel. This study not only prepared a robust and low-cost enzyme mimic, but also proposed a smart strategy to simultaneously monitor and remove toxic Hg2+ from contaminated water.