Solid-phase extraction method for preconcentration of cadmium and lead in environmental samples using multiwalled carbon nanotubes

摘要

A new sensitive and accurate solid-phase extraction method for preconcentration of trace amounts of cadmium and lead in various environmental samples prior to flame atomic absorption spectrometry determination has been developed. The proposed method is based on the utilization of multiwalled carbon nanotubes in combination with 5-benzyl-4-[-chlororbenzylidene amine]-4H-1,2,4-triazole-3-thiol (BCBATT) as a solid-phase sorbent with the aid of ultrasonication. The effect of the preconcentration parameters was investigated. Good recoveries ranging from 95% to 102% with relative standard deviations of 3.2% and 2.8% for Cd$^{2+}$ and Pb$^{2+}$, respectively, were obtained, indicating high accuracy and precision. The limits of detection were 0.2 and 0.5 $mu $g/L for Cd$^{2+}$ and Pb$^{2+}$, respectively. The preconcentration factor was 100. The validation of the proposed preconcentration procedure was performed using certified reference materials with satisfactory and compatible results. The proposed method was applied to various real environmental samples for determination of Cd$^{2+}$ and Pb$^{2+}$ concentrations and satisfactory results were obtained.