Palygorskite modified with N-doped carbon for sensitive determination of lead(II) by differential pulse anodic stripping voltammetry
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A glassy carbon electrode (GCE) was coated with N-doped carbon-modified palygorskite and used as an electrochemical sensor for determination of Pb(II) by differential pulse anodic stripping voltammetry. To obtain high reproducibility and sensitivity, optimum experimental conditions for lead deposition are studied. Voltammetric responses of the modified GCE prepared with different ratios of carbon and palygorskite are examined under same conditions. Compared with a bare GCE, a N-doped carbon modified/GCE and a bismuth-modified GCE, N-doped carbon-modified palygorskite greatly improves the performance of GCE. Response is the best and the interfacial impedance is minimized if the fraction of carbon coating is 31%. This indicates that its performance is due to the synergies between palygorskite and N-doped carbon. Figures of merit for the modified GCE include (a) a preconcentration time of 180 s, (b) a detection limit of 0.42 μg·L−1 (2σ criterion), and (c) a linear response in the 4.0 μg·L−1 to 10.0 mg·L−1 Pb(II) concentration range. The method is successfully applied to the determination of Pb(II) in spiked tape water and gives recoveries between 97.1 and 104.3%.
KeywordsClay-modified electrode Nanocomposite Modification of palygorskite Conductivity Electroanalysis Alternating current impedance method Detection of heavy metal ions Measurement of lead
We are greatly grateful for the National Natural Science Foundation of China (No. 51674293), and the Fundamental Research Funds for the Central Universities of Central South University (No. 502211709, 201810533077, 201810533573).
Compliance with ethical standards
Conflict of Interest
There are no conflicts of interest to declare.
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