Speciation of cadmium in human blood samples based on Fe3O4-supported naphthalene-1-thiol- functionalized graphene oxide nanocomposite by ultrasound-assisted dispersive magnetic micro solid phase extraction.

Cadmium (Cd) has toxic effect in human body and exists as the inorganic (Cd2+) and organic (R-Cd) forms in human biological matrix. Due to cadmium toxicity in various forms, the speciation of cadmium in human blood samples is very important. In this study, the Fe3O4-supported naphthalene-1-thiol- functionalized graphene oxide (Fe3O4@NpSH-GO, NMNT-GO) as a novel nanomagnetic composite was used for cadmium speciation in blood samples by ultrasound-assisted dispersive magnetic micro solid phase extraction (USA-DM-μ-SPE). By procedure, 20 mg of the NMNT-GO was used for extraction of Cd(II) from 1 mL of human blood samples at pH = 6.0, before determined by electrothermal atomic absorption spectrometry (ET-AAS). The total cadmium (T-Cd) was obtained by converting organic (R-Cd) to inorganic form (Cd2+), before adjusting pH and continuing with USA-DM- μ-SPE procedure. The organic cadmium was simply calculated by subtracting total cadmium from inorganic cadmium content. In optimized conditions, the linear range (peak area), limit of detection (LOD) and the preconcentration factor were obtained 30-1520 ng L-1, 10 ng L-1 and 4.88 in human blood samples, respectively (RSD: 1.1 %). The adsorption capacities of the Fe3O4@NpSH-GO and the GO were achieved 185.3 mg g-1 and 33.7 mg g-1 for inorganic cadmium, respectively. The results were validated by certified reference materials (CRM, NIST) and inductively coupled plasma mass spectrometry (ICP-MS) in human blood samples.