Determination of Zn2+ Cd2+ Pb2+ in food base on Bi-Co-BTC electrochemical sensor

Abstract

Objective: This study focused on the preparation of a new electrochemical sensor for detection of heavy metal content in food. Methods: In this study, a new type of bismuth-based metal-organic framework was prepared by hydrothermal method. 1,3,5-benzenetricarboxylic acid （H3BTC） was used as a ligand, which supplemented by bismuth nitrate pentahydrate [Bi（NO3）3 5H2O] and cobalt nitrate hexahydrate [Co（NO3）2·6H2O] metal salts to prepare novel bismuth-based metal-organic frameworks. Bi-based metal-organic framework composites supported by multi-walled carbon nanotubes were prepared by ultrasonic self-assembly. The surface of glassy carbon electrode （GCE） was modified by dropping casting. Results: The Bi-Co-BTC/MWCNTs/GCE was used as the working electrode to realize the simultaneous detection of Zn2+, Cd2+, and Pb2+ in the sample, and the detection limits were 0.040 3, 0.005 69, 0.023 9 ng/mL respectively. The recovery of Zn2+,Cd2+and Pb2+ in the tea were 97.21%~105.44%, 92.22%~106.10% and 93.97%~98.02%, respectively. Conclusion: The results show that Bi-MOF/MWCNTs/GCE can be used to detect the content of heavy metals in food.

Keywords

• bismuth metal-organic framework
• multi-walled carbon nanotubes
• electrochemical sensor
• heavy metal
• tea