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Li Yao,Xie Wang,Haitao Liu,Chaowen Lin,Liangyu Pang,Junwei Yang,Qingbin Zeng 한국공업화학회 2017 Journal of Industrial and Engineering Chemistry Vol.56 No.-
A simple and efficient method for the determination of Cd and Pb in water samples was developed byultrasound-assisted magnetic retrieval-linked ionic liquid dispersive liquid–liquid microextraction (UA-MR-IL-DLLME) preconcentration and graphite furnace atomic absorption spectrometry (GFAAS)detection. Ionic liquid (IL) [Hmim] [PF6] was used as the extractant, ammonium pyrrolidinedithiocarbamate (APDC) as the complexing agent and Fe3O4 nanoparticles as the sorbent, whileultrasound was applied to assist the dispersion of the extractant and accelerate the mass transfer process. The effect of different factors on the extraction efficiency including pH, IL volume, APDC amount,ultrasound extraction time, ultrasound desorption time and Fe3O4 amount was studied by a fractionalfactorial design to screen for the most important factors. Then a central composite design was used tooptimize the significant factors. Under the optimal conditions, the method has linear calibration curvesover the range of 0.3–20 ng/mL for Cd and 0.5–40 ng/mL for Pb, with correlation coefficients (R) of0.9990 and 0.9986 for Cd and Pb, respectively. The limits of detection were 0.1 ng/mL and 0.15 ng/mL withrelative standard deviations of 3.4% and 2.8% for Cd and Pb, respectively. Finally, the method wassuccessfully applied for the determination of Cd and Pb in the real water samples and satisfactoryrecoveries were achieved.
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.