title: Development of chip-based photocatalyst-assisted reduction device to couple high performance liquid chromatography and inductively coupled plasma-mass spectrometry for determination of inorganic selenium species.
abstract: In this study, a poly(methyl methacrylate) chip-based photocatalyst-assisted reduction device (PMMA chip-based PCARD) was developed as a reactor based on its excellent optical properties and ease of fabrication. Its transmittance of ultraviolet light at 365nm (UV365) was found to be as high as 92% using a PMMA of 2mm thickness. To optimize the vaporization efficiency, the effect of varying the depth of the geometry trenched on the PMMA-based chip was investigated. After optimization, it required only 29s of UV365 irradiation to vaporize the selenium (Se) species of interest. The PMMA-based chip was successfully used as an interfacing device for the hyphenation of high performance liquid chromatography (HPLC) separation and inductively coupled plasma-mass spectrometry (ICP-MS) detection. Additionally, under the optimized conditions for vaporization, using 1gL(-1) titanium dioxide nanoparticles (nano-TiO2) at pH 5, we found that Se(IV) and Se(VI) were converted quantitatively into volatile Se products. In addition, the optimized vaporization efficiency of the Se species of interest for the online HPLC/PMMA chip-based PCARD/ICP-MS system enabled us to achieve detection limits for Se(IV) and Se(VI) in the nanogram-per-liter range (based on 3σ). A series of validation experiments indicated that our proposed methods could be applied satisfactorily to the determination of inorganic Se species in environmental water samples.
authors.affiliation: Department of Biomedical Engineering and Environmental Sciences, National Tsing Hua University, 30013 Hisnchu, Taiwan.
authors.forename: Tsung-Ting
authors.initials: TT
authors.lastname: Shih
authors.forename: I-Hsiang
authors.initials: IH
authors.lastname: Hsu
authors.forename: Jung-Fu
authors.initials: JF
authors.lastname: Wu
authors.forename: Cheng-Hsing
authors.initials: CH
authors.lastname: Lin
authors.forename: Yuh-Chang
authors.initials: YC
authors.lastname: Sun
mesh_terms: D002384:Catalysis; D002851:Chromatography, High Pressure Liquid / Q000295:instrumentation*; D004867:Equipment Design; D056656:Lab-On-A-Chip Devices; D057230:Limit of Detection; D013058:Mass Spectrometry / Q000295:instrumentation; D053758:Nanoparticles / Q000737:chemistry; D019904:Polymethyl Methacrylate / Q000737:chemistry; D018036:Selenium Compounds / Q000032:analysis*; D014025:Titanium / Q000737:chemistry; D014466:Ultraviolet Rays; D014835:Volatilization; D014867:Water / Q000032:analysis*
chemical_list: D018036:Selenium Compounds; D014867:Water; C009495:titanium dioxide; D019904:Polymethyl Methacrylate; D014025:Titanium
keywords: Chip; Inductively coupled plasma-mass spectrometry (ICP-MS); Photocatalyst; Poly(methyl methacrylate) (PMMA); Selenium (Se); Vaporization