Dispersive micro-solid phase extraction method using newly prepared poly(methyl methacrylate) grafted agarose combined with ICP-MS for the simultaneous determination of Cd, Ni, Cu and Zn in vegetable and natural water samples

Poly(methyl methacrylate) grafted agarose (agarose-g-PMMA) was prepared as a new adsorbent for the simultaneous separation and preconcentration of trace amounts of cadmium(ii), nickel(ii), copper(ii) and zinc(ii) in vegetable and natural water samples with a simple and facile dispersive micro-solid phase extraction (D-μ-SPE) prior to ICP-MS detection. Agarose-g-PMMA was prepared by microwave-assisted free radical polymerization, and the materials obtained under optimum conditions in high percentage of grafting were characterized by FTIR, FE-SEM, DSC and TGA. The effective parameters of the extraction process, such as mass of adsorbent, pH of sample solution, adsorption time, type of eluent, concentrations and volume of eluent and desorption time were optimized. A preconcentration factor (PF) of 100 was obtained for trace metals with an elution time of 120 s. Under the optimum conditions, the limits of detection (LODs) for Cd, Ni, Cu and Zn were 1.8, 0.9, 0.6 and 1.5 ng L^-1 with relative standard deviations (RSDs) of 2.1%, 3.5%, 4.9% and 3.8%, respectively, at an analyte concentration of 10 ng L^-1, n = 7. The proposed method was successfully applied for the determination of heavy metals in vegetable and natural water samples with good relative recoveries in the range of 92.0-104.0%.