title: On-line electrochemically controlled in-tube solid phase microextraction of inorganic selenium followed by hydride generation atomic absorption spectrometry.
abstract: In this work, for the first time, a rapid, simple and sensitive microextraction procedure is demonstrated for the matrix separation, preconcentration and determination of inorganic selenium species in water samples using an electrochemically controlled in-tube solid phase microextraction (EC-in-tube SPME) followed by hydride generation atomic absorption spectrometry (HG-AAS). In this approach, in which EC-in-tube SPME and HG-AAS system were combined, the total analysis time, was decreased and the accuracy, repeatability and sensitivity were increased. In addition, to increases extraction efficiency, a novel nanostructured composite coating consisting of polypyrrole (PPy) doped with ethyleneglycol dimethacrylate (EGDMA) was prepared on the inner surface of a stainless-steel tube by a facile electrodeposition method. To evaluate the offered setup and the new PPy-EGDMA coating, it was used to extract inorganic selenium species in water samples. Extraction of inorganic selenium species was carried out by applying a positive potential through the inner surface of coated in-tube under flow conditions. Under the optimized conditions, selenium was detected in amounts as small as 4.0 parts per trillion. The method showed good linearity in the range of 0.012-200 ng mL(-1), with coefficients of determination better than 0.9996. The intra- and inter-assay precisions (RSD%, n = 5) were in the range of 2.0-2.5% and 2.7-3.2%, respectively. The validated method was successfully applied for the analysis of inorganic selenium species in some water samples and satisfactory results were obtained.
authors.affiliation: Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran.
authors.forename: Hamid
authors.initials: H
authors.lastname: Asiabi
authors.affiliation: Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran. Electronic address: yyamini@modares.ac.ir.
authors.forename: Yadollah
authors.initials: Y
authors.lastname: Yamini
authors.affiliation: Department of Analytical Chemistry, Faculty of Chemistry, K.N. Toosi University of Technology, Tehran, Iran.
authors.forename: Shahram
authors.initials: S
authors.lastname: Seidi
authors.affiliation: Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran.
authors.forename: Maryam
authors.initials: M
authors.lastname: Shamsayei
authors.affiliation: Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran.
authors.forename: Meysam
authors.initials: M
authors.lastname: Safari
authors.affiliation: Department of Chemistry, Tarbiat Modares University, P.O. Box 14115-175, Tehran, Iran.
authors.forename: Fatemeh
authors.initials: F
authors.lastname: Rezaei
keywords: Electrochemically control; In-tube solid phase microextraction; Nanostructured composite; Poly ethyleneglycol dimethacrylate; Polypyrrole; Selenium