Voltammetric detection of mercury(II) using lead powder-modified thiol-functionalized polysiloxane film electrode

Abstract

Surfactant-templated silica films functionalized with thiol groups and modified with lead powder have been deposited during one-step process onto glassy carbon electrodes. This strategy was based on co-condensation of tetraethoxysilane and 3- mercaptopropyltrimethoxysilane in the presence of cetyltrimethylammonium bromide, and modification of sol by the appropriate amount of lead powder. After template extraction, the novel lead powder modified thiol-functionalized polysiloxane film electrode was applied to the determination of Hg(II). The obtained results indicated that the sensitivity at this electrode was remarkably improved with relative to the thiol-functionalized polysiloxane film electrode prepared without use of the lead powder. Various parameters have been optimized to get the highest current response, such as the film composition, accumulation time, detection conditions, and concentration of analyte. Linear calibration curve was obtained in the Hg(II) concentration range from 5 × 10−8 to 1 × 10−5 mol L−1 for the accumulation time of 60 s. The detection limit estimated from 3 times the standard deviation for the lowest determined concentration of Hg(II) was equal to 1.9 × 10−8 mol L−1. It has to be noted, that the detection limit can easily be improved by the prolongation of the accumulation time up to 30 min.