Determination of Trace Lead Detection in a Sample Solution by Liquid Three-Phase Microextraction–Anodic Stripping Voltammetry
Herein, the micro extraction and quantification of lead (II) ions were investigated in trace levels on in situ pulse anodic stripping voltammetry (DPASV) and polytetrafluorethylene (PTFE) membrane-based liquid three-phase micro extraction. The voltammetric cell contained the acceptor solution and reference, the counter, and working electrodes. The modified Pt electrode with 3-Trimethoxysilyl-1-propanethiol and gold nanoparticles (Au NPs), respectively, was applied as the working electrode. The voltammetric cell combined with DPASV was utilized in situ during the extraction time. The obtained results showed the effect of different factors on the pre-concentration and micro extraction of lead ions, including the organic solvent, pH of the donor and acceptor phases, concentration of the complexion agent, extraction time, stirring rate, and electrochemical factors; also, the optimal extraction conditions were established. The final stable signal was achieved after 18-min extraction time for analytical applications. The relative standard deviation and the enrichment factor were obtained to be 6.0% (n =5) and 18, respectively. The calibration curve was obtained in the range of 0.207-62.1 ppb Pb(II) (analytical equation: y = 3.986 x + 0.381), and the limit of detection was found to be 0.021 ppb with optimum conditions. The lead (II) ions were determined in fish, rice, and wastewater samples.