The incorporation of bismuth(III) into metal-organic frameworks for electrochemical detection of trace cadmium(II) and lead(II)
The first example of metallic bismuth encapsulated into a mesoporous metal-organic framework of the type MIL-101(Cr) matrix is presented. Bi(III)-impregnated MIL-101(Cr) (Bi(III)/MIL-101(Cr)) was dropped onto a conductive carbon cloth electrode (CCE). Then, bismuth was generated by electrochemical reduction of the Bi(III)/MIL-101(Cr) supported on CCE (Bi/MIL-101(Cr)/CCE). The resulting Bi/MIL-101(Cr)/CCE display impressive performance in terms of peak currents for the ions Cd(II) and Pb(II) when compared to the single-component counterparts. Differential pulse anodic stripping voltammetry (DPASV) enabled sensing of the two ions over linear working range of 0.1 to 30 μg L−1 and 30 to 90 μg L−1. The parameters are refined before the detection of two metal ions, including the amount of bismuth in MIL-101(Cr), optimum pH (5.0), deposition potential (−1.2 V) and deposition time (600 s). The respective detection limits are 60 and 70 ng L−1 (at S/N = 3). This is strikingly lower than the guideline values of domestic water given by the WHO which are 3 μg L−1 for Cd(II) and 10 μg L−1 for Pb(II). The Bi/MIL-101(Cr) onto CCE is fairly specific for Cd(II) (at around −0.76 V) and Pb(II) (at around −0.54 V), well reproducible and has excellent recovery in real water analysis.
KeywordsMetal-organic frameworks (MOFs) Bismuth/MOF Differential pulse anodic stripping voltammetry (DPASV) Cd(II) and Pb(II) detection
The authors acknowledge financial support from the National Natural Science Foundation of China (Nos. 21771047, 21403048, 21401147 and 21571045), University Nursing Program for Young Scholars with Creative Talents in Heilongjiang Province (No. UNPYSCT-2017183), Harbin Science and Technology Bureau (2016RAQXJ161), and PhD Research Startup Program of Harbin Normal University, China (No. XKB201310).
Compliance with ethical standards
The author(s) declare that they have no competing interests.
- 6.Zhou J, Li X, Yang L, Yan S, Wang M, Cheng D, Chen Q, Dong Y, Liu P, Cai W, Zhang C (2015) The Cu-MOF-199/single-walled carbon nanotubes modified electrode for simultaneous determination of hydroquinone and catechol with extended linear ranges and lower detection limits. Anal Chim Acta 899:57–65CrossRefGoogle Scholar