Cloud point assisted dispersive ionic liquid -liquid microextraction for chromium speciation in human blood samples based on isopropyl 2-[(isopropoxycarbothiolyl)disulfanyl] ethane thioate

An efficient and fast method based on isopropyl 2-[(isopropoxycarbothiolyl)disulfanyl] ethane thioate (IICDET) were used for the speciation and determination of trace amount of Cr(III and VI) in human biological samples by cloud point assisted dispersive ionic liquid –liquid microextraction (CP-DILLME). Cr(VI) has carcinogenic effects, so, speciation of chromium in human body such as blood cells is very important. The cloudy solution was achieved by the mixture of acetone and IL ([C₈MIM][PF₆]) in human blood samples containing Cr(III) ions that were already complexed by IICDET at pH 4.5. After reduction Cr(VI) to Cr(III) by ascorbic acid, chromium speciation was obtained based on total chromium determination by electro thermal atomic absorption spectrometry (ET-AAS) and difference between total Cr and Cr(III) content. In addition, Cr speciation in human blood cells was calculated based on IICDET/CP-DILLME and hematocrit blood test (HCT). After optimized conditions, the enrichment factor (EF), Linear range and limit of detection (LOD) was obtained 25.2, 0.02–1.75 μg L⁻¹ and 5.4 ng L⁻¹ in human biological samples respectively. The validation of methodology was achieved by certified reference material (CRM) and ICP-MS technique.