title: Flow injection microfluidic device with on-line fluorescent derivatization for the determination of Cr(III) and Cr(VI) in water samples after solid phase extraction.
abstract: In this paper, a rapid and simple method using magnetic multi-walled carbon nanotubes (MWCNTS), as a solid-phase extraction (SPE) sorbent, was successfully developed for extraction and preconcentration trace amounts of Cr(III) in water samples. The synthesized magnetic-MWCNTs nanocomposite was characterized by scanning electron microscopy (SEM), transmission electron microscopy (TEM), Fourier transform infrared spectroscopy (FT-IR), X-ray photoelectron spectroscopy (XPS) and X-ray diffraction (XRD). A rhodamine derivative (R1) was synthesized and characterized as a highly selective and sensitive fluorescent derivatizing agent for Cr(III). After SPE procedure, Cr(III) analysis was performed by flow injection microfluidic chip with on-line fluorescent derivatization and laser-induced fluorescence (LIF) spectroscopy detection. The parameters, which affected the efficiency of the developed method were investigated and optimized. Under the optimized conditions, the method exhibited a linear dynamic range of 0-10.0 nM, with a detection limit of 0.094 nM and an enrichment factor of 38. Furthermore, real water samples were analyzed and good recoveries were obtained from 91.0 to 101.6%.
authors.affiliation: Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, 400045, China; Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084, China.
authors.forename: Guilong
authors.initials: G
authors.lastname: Peng
authors.affiliation: Key Laboratory of Eco-Environment of Three Gorges Region of Ministry of Education, Chongqing University, Chongqing, 400045, China. Electronic address: heqiang0980@163.com.
authors.forename: Qiang
authors.initials: Q
authors.lastname: He
authors.affiliation: Department of Mathematics and Physics, Armed Police College, Chengdu, 610213, China.
authors.forename: Ying
authors.initials: Y
authors.lastname: Lu
authors.affiliation: Research Center for Advanced Computation, College of Science, Xihua University, Chengdu, 610039, China.
authors.forename: Jing
authors.initials: J
authors.lastname: Huang
authors.affiliation: Department of Chemistry, Beijing Key Laboratory of Microanalytical Methods and Instrumentation, Tsinghua University, Beijing, 100084, China. Electronic address: jmlin@mail.tsinghua.edu.cn.
authors.forename: Jin-Ming
authors.initials: JM
authors.lastname: Lin
keywords: Flow injection microfluidic chip; Laser-induced fluorescence spectroscopy; Magnetic multi-walled carbon nanotubes; Solid-phase extraction