Efficacy of dihydroxy-mercaptopyrimidine functionalized polymeric resin for the trace determination of Cd by SPE coupled flame atomic absorption spectrometry

Abstract

A novel 2-thiobarbituric acid functionalized polystyrene resin has been explored for its efficacy and applicability in solid phase preconcentration coupled atomic absorption spectrometric determination of trace cadmium. The prepared resin was characterized by infrared spectroscopy, scanning electron microscopy, energy dispersive X-ray analysis, and thermogravimetry. The maximum static sorption capacity of the prepared resin was 131.58 mg Cd g⁻¹ resin with a low preconcentration limit of 2.5 μg L⁻¹. The experimental parameters affecting the solid phase extraction of cadmium including sample pH, sorption time, flow rate for sorption and desorption, volume and concentration of the eluent, sample volume and concomitant ions were investigated. Under the optimized conditions, <0.008 standard deviation was observed in the absorbance of the quantitatively recovered 1 μg mL⁻¹ Cd even in the presence of common matrix ions. The linearity was maintained between 2.5–90.0 μg L⁻¹ with R² = 0.999. The good precision of the method was assessed by the resulting average inter column and inter day coefficient of variations of 3.34% and 3.07%, respectively. The accuracy of the method was verified by determining the Cd content in the Standard Reference Material (SRM) NIES-10c and by recovery experiments in spiked real samples. The proposed method was successfully used to preconcentrate cadmium from commonly consumed samples like cigarettes, rum, coffee, tap water and water after reverse osmosis with >96% recovery.