Flame atomic absorption spectrometric determination of trace amounts of cadmium after dispersive solid phase microextraction using modified magnetic graphene oxide as the sorbent

Cadmium is a highly toxic element for humans and animals and can be accumulated in liver, kidneys, and lungs. Cadmium is mainly obtained as a by-product in the hydrometallurgical processing of metals such as copper, zinc and lead; and it is found in industrial dust, tobacco smoke, food and some water supplies. Therefore, there is an interesting request to monitor trace levels of cadmium in different biological, environmental and water samples [1-3].In this study, a simple and sensitive dispersive solid phase microextraction method for the separation and preconcentration of cadmium using 1-hexadecyl-3-methylimidazolium bromide ([C16MIM]Br)-coated magnetic graphene oxide nanoparticles (IL@mGO) as the sorbent has been developed. Cadmium in the solution is converted to the anionic complex of CdI42- and preconcentrated on the positively charged surface of the sorbent. Then, the preconcentrated cadmium was desorbed from the sorbent and determined by flame atomic absorption spectrometry. Factors affecting the extraction efficiency such as pH, sample volume, amount of the sorbent, extraction time, type, volume and concentration of eluent were investigated and optimized. Under the optimum conditions, a linear dynamic range of 0.2-12.5 µg L-1 was achieved for Cd(II). The limit of detection (LOD) was 0.05 µg L-1 ¬¬¬¬¬¬and the relative standard deviation at 2 µg L-1 level of cadmium (n = 8) was 3.7%. The method was applied for the determination of cadmium in biological and water samples.