Simultaneous clean-up and determination of Cu(II), Pb(II) and Cr(III) in real water and food samples using a magnetic dispersive solid phase microextraction and differential pulse voltammetry with a green and novel modified glassy carbon electrode

Abstract

A simple and efficient magnetic dispersive solid phase microextraction as a clean-up step was developed to simultaneous extraction of Cu(II), Pb(II) and Cr(III) in real water and food samples prior to their determination with differential pulse voltammetry (DPV). Four derivatives of β-cyclodextrin α-amino acid (methionine, valine, phenylalanine, and tryptophan) were prepared and applied for modification of glassy carbon electrodes as novel and green electrochemical sensors. The performance of four modified glassy carbon electrodes was compared together for the determination of Cu(II), Pb(II) and Cr(III). In addition, a novel SPME sorbent, magnetic diethylenetriamine functionalized graphene oxide nanocomposites were synthesized for clean-up and extraction of the analytes, and its characterization was studied through SEM images and FTIR spectra. Design of experiment approach was used for optimization of the effective factors in microextraction procedure such as pH of the sample solution, sample solution, and desorption solvent volume, amount of sorbent, dispersion time, extraction and desorption time. The proposed method had a suitable linear range with high repeatability and well stability to measure the analytes. Limit of quantitation (LOQs) and the relative standard deviations (RSDs, n = 5) were lower than 0.5 ng mL−1 and 4.3% for all analytes, respectively. Analysis of several real samples such as tap water, river water, well water, apple juice, and rice samples indicated that the method is an appropriate, sensitive and accurate procedure for the determination of these analytes in various real samples with relative recoveries of higher than 86.4.