Cadmium separation in human biological samples based on captopril-ionic liquid paste on graphite rod before determination by electrothermal atomic absorption spectrometry

A mixture of captopril nanoparticles (CAP-NPs) and ionic liquid (IL, [HMIM] [PF6]) paste on micro graphite rod (CAP-IL-MGR) and was used for separation cadmium in human serum and urine samples by micro solid phase extraction (μ-SPE). 0.01 g of CAP-NPs and 0.1 g of [HMIM] [PF6] mixed with 1 mL of acetone and mixture passed physically on micro graphite rod (MGR) at 55o C. Then, the graphite probe placed on 10 mL of human biological samples with 5 min of sonication, then cadmium ions complexed by thiol group of captopril (CAP-SH) at pH=5.5. The cadmium ions on micro probe were back extracted with 0.25 mL of nitric acid (0.5 M) which was diluted with DW up to 0.5 mL and finally, the cadmium concentration determined by ET-AAS. By optimizing of amount of captopril, the absorption capacity and recovery were obtained 132.4 mg g-1 and more than 96%, respectively. The limit of detection (LOD), linear range (LR) and enrichment factor (EF) were achieved 2 ngL^-1, 0.01-0.35 μg L^-1 and 19.7, respectively (RSD % 5%). The validation was done by certified reference material (CRM, NIST) and ICP-MS analysis.