Arsenic preconcentration viasolid phase extraction and speciation by HPLC-gradient hydride generation atomic absorption spectrometry

Abstract

A novel method for arsenic speciation is developed by interfacing solid phase preconcentration-liquid chromatography (LC) separation-gradient hydride generation (GHG)-quartz flame atomic absorption spectrometry (QFAAS). A MnO 2 mini-column is used to preconcentrate the arsenic species of As(III), As(V), MMA and DMA, during which process, As(III) is converted to As(V) via oxidation by MnO 2 , while other species remain unchanged. The recovery of As(V) (i.e., the total amount of arsenate and arsenite in the original sample), MMA and DMA from the MnO 2 mini-column is facilitated by tetramethylammonium hydroxide (TMAH). After LC separation with C30 columns, arsenic species in the eluate are subject to gradient hydride generation with detection by QFAAS. On the other hand, cellulose fibre selectively adsorbs the chelating complex between As(III) and ammonium pyrrolidine dithiocarbamate (APDC). After elution with HNO 3 , As(III) in the original sample is quantified by graphite furnace atomic absorption spectrometry (GFAAS), and the amount of As(V) is obtained by subtraction. A sample volume of 2.0 mL derives enrichment factors of 14.0-19.2 for the arsenic species. By injecting 20 mL of eluate into the LC system (the eluate of As(III)-PDC complex is injected into the GFAAS), detection limits of 0.019, 0.33, 0.39, 0.62 mg L À1 are obtained for As(III), As(V), MMA and DMA respectively. RSDs of less than 4.2% are achieved at the level of 2 mg L À1 for As(V), MMA, DMA and 1 mg L À1 for As(III). The procedure is evaluated by speciating arsenic in snow water and Hijiki samples.

Simultaneous speciation of inorganic arsenic, selenium and tellurium in environmental water samples by dispersive liquid liquid microextraction combined with electrothermal vaporization inductively coupled plasma mass spectrometry

“…They are more diffused than the chromatographic techniques for a simple elemental speciation, especially valence state of As, Se and Te. Among these non-chromatographic techniques, such as liquid liquid extraction, solid phase extraction [16][17][18], solid phase microextraction (SPME) [19], cloud point extraction (CPE) [20,21] and liquid phase microextraction (LPME) [22][23][24], LPME possesses merits of solvent-less, low cost, high enrichment factors, easy-to-operate and shows great potential in trace analysis.…”

Measurement of arsenic species in environmental, biological fluids and food samples by HPLC-ICPMS and HPLC-HG-AFS

“…The major conclusion is that it is essential to ensure that As species, especially in waters and sediments, are not artefacts of the preservation or extraction procedure. oxidation of As(III) to As(V) can be facilitated by the presence of Fe(III), MnO 2 and dissolved organic matter [34][35][36]. Arsenic cannot be extracted from samples using a single set of conditions but must be optimised for each sample type.…”

Speciation analysis of arsenic compounds by capillary electrophoresis on-line coupled with inductively coupled plasma mass spectrometry using a novel interface

“…There are already some methods for the speciation of arsenic species by coupling high performance liquid chromatography (HPLC), gas chromatography (GC) and capillary electrophoresis (CE) with atomic fluorescence spectrometry (AFS), atomic absorption spectrometry (AAS) and inductively coupled plasma mass spectrometry (ICP-MS) [3,[7][8][9][10][11][12][13][14][15]. GC has a great separation capacity for volatile arsenicals, but its application is limited because most naturally occurring arsenic species are non-volatile and have to be derivatized before further analysis.…”