Inorganic selenium speciation in water and biological samples by three phase hollow fiber-based liquid phase microextraction coupled with HPLC-UV

Abstract

A rapid, sensitive, high clean-up and economic three phase hollow fiber liquid phase microextraction method followed by HPLC-UV was applied for speciation of inorganic selenium in water and biological samples.

Separation of selenium species in plant tissues by high performance liquid chromatography-ultraviolet treatment-hydride generation atomic fluorescence spectrometry using various mobile phases

“…When 60 mmol L −1 (NH 4 ) 2 HPO 4 served as the mobile phase, the retention times of organic Se (SeCys and SeMet) slightly increased with the increase in pH, while the retention times of inorganic selenium [Se (IV) and Se (VI)] were reduced, and the retention time of Se (VI) was reduced greatly (Figure 3). This was in agreement with the findings of previous studies [31,32], the retention time of Se (VI) decreased with the increase of pH using 40 mmol L −1 phosphate buffer as the mobile phase [30], while only Se(IV) and Se(VI) were detected with pH up to 8, and the chromatographic peaks of SeCys2, MeSeCys and SeMet were not found with 40 mmol L −1 (NH 4 ) 2 HPO 4 as the mobile phase [32]. In addition, pH also influenced the peaks of various Se species.…”

“…However, when the mobile phase was 40 mmol L −1 NH 4 H 2 PO 4 at pH 4.48, only SeCys, SeMet and Se (IV) were detected (Figure 1A); and only SeCys and Se (IV) was separated using 40 mmol L −1 NH 4 Ac at pH 6.94 and 40 mmol L −1 NH 4 NO 3 at pH 5.18 as the mobile phase as shown in Figure 1B and Figure 1C. The Se (VI) were not eluted because of their higher charge on the species under the eluent pH used, leading to their strong retention on the column [29,30]. On the other hand, competing anions such as Acand NO 3 were too weak to elute SeMet and Se(VI) from the column [23].…”