Organic and inorganic selenium speciation in environmental and biological samples by nanometer‐sized materials packed dual‐column separation/preconcentration on‐line coupled with ICP‐MS

Abstract

A novel, fast, and cheap nonchromatographic method for direct speciation of dissolved inorganic and organic selenium species in environmental and biological samples was developed by flow injection (FI) dual-column preconcentration/separation on-line coupled with ICP-MS determination. In the developed technique, the first column packed with nanometer-sized Al(2)O(3) could selectively adsorb the inorganic selenium [Se(IV), Se(VI)], and the retained inorganic selenium could be eluted by 0.2 mol l(-1) NaOH, while the organic Se [selenocystine (SeCys(2)) and selenomethionine (Se-Met)] was not retained. On the other hand, the second column packed with mesoporous TiO(2) chemically modified by dimercaptosuccinic acid (DMSA) could selectively adsorb Se(IV) and SeCys(2) and barely adsorb Se(VI) and Se-Met. When the sample solution was passed through the column 1, separation of inorganic selenium and organic selenium could be achieved first. Then, the effluent from column 1 was successively introduced into the column 2 and the speciation of organic selenium could be attained due to the different adsorption behaviors of Se-Met and SeCys(2) on DMSA modified TiO(2). After that, the eluent from column 1 contained Se(IV), and Se(VI) was adjusted to desired pH and injected into column 2, and the speciation of Se(IV) and Se(VI) could also be realized thanks to their different retention on column 2. The parameters affecting the separation were investigated systematically and the optimal separation conditions were established. The detection limits obtained for Se(IV), Se(VI), Se-Met and SeCys(2) were 45-210 ng l(-1) with precisions of 3.6-9.7%. The proposed method has been successfully applied for the speciation of dissolved inorganic and organic selenium in environmental and biological samples. In order to validate the methodology, the developed method was also applied to the speciation of selenium in certified reference material of SELM-1 yeast, and the determined values were in good agreement with the certified values.

Notice of Retraction: Determination of Selenium Speciation in Tea Samples by HPLC-DRC-ICP-MS

“…The regular consumption of tea may contribute to the daily dietary requirements of several essential elements. Considering the enormous consumption of tea and the investigation focusing on selenium, it is necessary to study selenium speciation in tea samples [6]. While there were still nearly few literatures concerning investigation on selenium speciation in tea samples based on high performance liquid chromatography (HPLC) coupled with inductively coupled plasma mass spectrometry (ICP-MS).…”

Nanometer‐sized alumina packed microcolumn solid‐phase extraction combined with field‐amplified sample stacking‐capillary electrophoresis for the speciation analysis of inorganic selenium in environmental water samples

“…The adsorption performance and coexisting ions interference of nanometer‐sized Al 2 O 3 has been evaluated in our previous research works . In the analysis of inorganic and organic Se species by using nanometer‐sized Al 2 O 3 and dimercaptosuccinic acid modified mesoporous TiO 2 packed column, it had been demonstrated that 4 g L −1 K + and Na + , 2 g L −1 Ca 2+ and Mg 2+ , 50 mg L −1 Al 3+ , 10 mg L −1 Fe 3+ , 3 g L −1 NO 3 − and Cl − , 1 g L −1 SO 4 2− , and 50 mg L −1 Br − would hardly affect the recoveries of target Se species . Therefore, only coexisting ions that would affect the CE separation of Se (VI/IV) were considered in this work.…”

“…Compared with these low‐cost SPE adsorbents, nanometer‐sized materials are featured with much higher surface area and more activated sites for adsorption due to their unique size and physical properties. In our previous works, the adsorption behaviors of some metal ions on nanometer‐sized TiO 2 and Al 2 O 3 had been systematically studied , and the methods of SPE‐ICP‐optical emission spectrometry (OES)/MS based on nanometer‐sized oxides as adsorbents were established for the determination of trace metals and also speciation analysis of inorganic selenium and seleno amino acids .…”

Determination of Cr(VI) and Cr(III) species in parenteral solutions using a nanostructured material packed-microcolumn and electrothermal atomic absorption spectrometry

“…Solid phases with these characteristics make possible to build columns with small volume and high retention capacity, which enables in turn the determination of the analyte at trace levels, and using low volumes of eluent and wastes. Thus, micro-and mini-columns packed with nanometersized materials have been used for speciation of dissolved inorganic and organic Se species [20], simultaneous determination of trace metals (V, Cr, Mn, Co, Ni, Cu, Zn, Cd and Pb) [17]. Moreover, nanostructured TiO 2 has been employed for speciation of Cr(III) and Cr(VI) in environmental samples [21,22].…”