Application of Supramolecular Microextraction and Flame Atomic Absorption Spectrometry for Ultra-trace Determination of Cadmium in Food and Water Samples

In this work, a supramolecular microextraction procedure for trace cadmium as 1,2,4 thiadiazole-2,5 dithiol chelates has been established. Flame atomic absorption spectrometry was used for the determination of cadmium. A rapid injection of 600 L tetrahydrofuran and 200 L of 1-decanol in a sample solution containing cadmium at pH 8 leads to formation of a cloudy solution by ultrasonic waves. Then the supramolecular organic solvent mixture, including the chelated cadmium, was separated by centrifugation. Certified reference materials (TMDA 64.2 and TMDA 53.3) were tested and the determined concentrations were in agreement with the certified values. Furthermore, the method resulted in an LOD of 0.46 g L -1 , LOQ of 1.37 g L -1 , and RSD of 5.1%. The supramolecular microextraction procedure was successfully applied for the analysis of environmental samples including wastewater, seawater, dam water, valley water, and black pepper.