Bismuth-based metal-organic framework peroxidase-mimic nanozyme: Preparation and mechanism for colorimetric-converted ultra-trace electrochemical sensing of chromium ion

• Published in: Journal of hazardous materials 2023-06, Vol.451, p.131148-131148, Article 131148
• Main Authors: Yang, Qiu-Yu, Wan, Chao-Qun, Wang, Yu-Xin, Shen, Xiao-Fang, Pang, Yue-Hong
• Format: Article
• Language: English
• Subjects: Bismuth; Chromium; Chromium ion; Colorimetry - methods; Electrochemical/colorimetric sensor; Hydrogen Peroxide; Metal-organic framework; Metal-Organic Frameworks; Nanozyme; Peroxidase; Peroxidases
• ISSN: 0304-3894; 1873-3336
• DOI: 10.1016/j.jhazmat.2023.131148

A colorimetric-electrochemical dual-mode analytical method based on bismuth metal-organic framework nanozyme was developed for label-free and trace/ultra-trace Cr6+ detection. 3D ball-flower shaped bismuth oxide formate (BiOCOOH) was used as the precursor and template to facilely construct the metal-organic framework nanozyme BiO-BDC-NH2, which possesses intrinsic peroxidase-mimic activity to effectively catalyze the colorless 3,3′,5,5′-tetramethylbenzidine into blue oxidation products in the presence of hydrogen peroxide. Based on Cr6+ to promote the peroxide-mimic activity of BiO-BDC-NH2 nanozyme, a colorimetric method for Cr6+ detection was developed with the detection limit of 0.44 ng mL−1. Cr6+ can be electrochemically reduced to Cr3+ that would specifically inhibit the peroxidase-mimic activity of BiO-BDC-NH2 nanozyme. Thus, the colorimetric system for Cr6+ detection was converted into a low-toxic and signal-off electrochemical sensor. The electrochemical model showed upgraded sensitivity and a lower detection limit of 9.00 pg mL−1. The dual-model method was developed for selective appropriate sensing instruments in different detection scenarios, which can provide built-in correction for environmental effects, as well as the development and utilization of dual-signal sensing platforms for trace to ultra-trace Cr6+ rapid assay. [Display omitted] •A bismuth-based MOF nanozyme with 3D ball-flower shape was constructed.•The MOF showed Cr6+-promoted and Cr3+-inhibited peroxidase-mimic activity.•A dual-model colorimetric-electrochemical sensor for trace to ultra-trace Cr6+ detection.•The colorimetric model can convert into sensitive electrochemical model.