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Li Yao,Yongqun Zhu,Wenzhi Xu,Hong Wang,Xie Wang,Jianhua Zhang,Haitao Liu,Chaowen Lin 한국공업화학회 2019 Journal of Industrial and Engineering Chemistry Vol.72 No.-
In this study, the combination of dispersive solid phase extraction (DSPE) with dispersive liquid–liquidmicroextraction (DLLME) was proposed as a novel sequential speciation method for Cr determination bygraphite furnace atomic absorption spectrometry. In thefirst step, the selective extraction of Cr(III) byDSPE was achieved using graphene oxide (GO) nanoparticles as the adsorbent. The difficulty of separationand collection of GO in analytical performance was solved by the introduction of the syringe nanofilter. Then Cr(VI) was enriched by DLLME using [Omim] [PF6] as the extraction solvent. The experimentalparameters affecting the performance of both preconcentration methods were investigated andoptimized. Under the optimal conditions including the initial pH value of 7, 150 mg GO, 2 min ultrasoundtime, 210 mL elution solvent (first step), secondary pH value of 4, 0.15% (m/v) Aliquat-336, 120 mL of[Omim] [PF6] and 3 min ultrasound time (second step), the linear range of 0.06–5 ng/mL (R > 0.997), thelimits of detection of 0.015 and 0.02 ng/mL were achieved for Cr(III) and Cr(VI), respectively. The relativestandard deviations (n = 5) of 0.6 ng/mL Cr(III) and Cr(VI) were 3.2% and 4.6%, respectively. Finally, thisnewly developed method was applied for the speciation and determination of Cr species in differentwater samples and satisfactory results were obtained.