An electrochemical assay for the determination of Se (IV) in a sequential injection lab-on-valve system

College of Chemistry and Chemical Engineering, Yangzhou University, Yangzhou 225002, China.
Analytica chimica acta (Impact Factor: 4.51). 10/2009; 649(1):75-9. DOI: 10.1016/j.aca.2009.06.055
Source: PubMed


A sequential injection lab-on-valve (LOV) unit, integrating a miniaturized electrochemical flow cell (EFC), has been constructed for the determination of trace amounts of Se (IV) by employing cathodic stripping voltammetry (CSV) technique. The procedure is carried out on a mercury film coated glassy carbon electrode. The analyte solution and electrolyte solution were continuously aspirated and merged in the holding coil (HC) by using a single syringe pump, which were afterwards pushed into the EFC, where the peak current was generated during the subsequent deposition/stripping procedure and measured as the basis of quantification. Assay parameters were optimized in order to achieve the best analytical performance, including mercury film preparation, supporting electrolyte composition, deposition potential and deposition time, and flow variables in the LOV. By loading a sample volume of 500 microL, a linear calibration graph was derived within 1-600 microg L(-1), and a detection limit (3b) of 0.11 microgL(-1) was achieved along with a sampling frequency of 20 h(-1). By integrating the EFC into the LOV unit, the assembling system not only minimized the sample/reagent consumption and waste generation, but also enhanced the sampling frequency. The work itself extended the applications of electrochemical detection techniques and provided a good platform for Se (IV) electrochemical analysis.

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    • "Flow based methods provide automation for sample preparation and detection. Flow based techniques incorporating with hydride generation-atomic absorption spectrometry (Zhang and Adeloju 2008; Mena et al. 1999), hydride generation-atomic fluorescence spectrometry (Semenova et al. 2003; Gamiz-Gracia and Luque de Castro 1999), fluorometry (Pedro et al. 2004), spectrometry (Nakano, Yoshii, and Kawashima 2004; Mousavi, Ghiasvand, and Jahanshahi 1998), and voltammetry (Wang et al. 2009) were applied for determination of selenium in various samples such as food, pharmaceutical, and environmental samples. "
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