Selective hydride generation-cryotrapping-ICP-MS for arsenic speciation analysis at picogram levels: analysis of river and sea water reference materials and human bladder epithelial cells

Abstract

An ultra sensitive method for arsenic (As) speciation analysis based on selective hydride generation (HG) with preconcentration by cryotrapping (CT) and inductively coupled plasma- mass spectrometry (ICP-MS) detection is presented. Determination of valence of the As species is performed by selective HG without prereduction (trivalent species only) or with L-cysteine prereduction (sum of tri- and pentavalent species). Methylated species are resolved on the basis of thermal desorption of formed methyl substituted arsines after collection at −196°C. Limits of detection of 3.4, 0.04, 0.14 and 0.10 pg mL−1 (ppt) were achieved for inorganic As, mono-, di- and trimethylated species, respectively, from a 500 μL sample. Speciation analysis of river water (NRC SLRS-4 and SLRS-5) and sea water (NRC CASS-4, CASS-5 and NASS-5) reference materials certified to contain 0.4 to 1.3 ng mL−1 total As was performed. The concentrations of methylated As species in tens of pg mL−1 range obtained by HG-CT-ICP-MS systems in three laboratories were in excellent agreement and compared well with results of HG-CT-atomic absorption spectrometry and anion exchange liquid chromatography- ICP-MS; sums of detected species agreed well with the certified total As content. HG-CT-ICP-MS method was successfully used for analysis of microsamples of exfoliated bladder epithelial cells isolated from human urine. Here, samples of lysates of 25 to 550 thousand cells contained typically tens pg up to ng of iAs species and from single to hundreds pg of methylated species, well within detection power of the presented method. A significant portion of As in the cells was found in the form of the highly toxic trivalent species.

Vapor generation – atomic spectrometric techniques. Expanding frontiers through specific-species preconcentration. A review

“…A series of studies have been undertaken by J. Dědina et.al. in the last 5 years [47,50,51] in the matter of arsenic speciation. The applicability of a criotrapping automatic device developed some years ago [116] was demonstrated.…”

“…Preconcentrarion strategies have also been described for the volatile species generated in the VG technique resulting in the so called gas-phase trapping [44][45][46][47][48][49][50][51][52][53].…”

Chemical Generation of Arsane and Methylarsanes with Amine Boranes. Potentialities for Nonchromatographic Speciation of Arsenic

“…The method of selective determination of DMAA was tested on CASS-4, SLRS-4, and NASS-5 natural waters, certified for total As, which have been recently analyzed for arsenic speciation by Matousek et al by selective hydride generationcryotrapping-ICP-MS. 8 These differences are not easy to explain, and conclusions cannot be drawn in the absence of certified reference samples. Nevertheless, the results are encouraging, and the analytical scheme could be useful for those less-favored laboratories which have to face arsenic speciation by using simple and inexpensive equipments.…”

“…8,9 Methods employed for the speciation of the different arsenic forms, like hydride generation, voltammetry, and chromatography (liquid chromatography, including high-performance liquid chromatography and gas chromatography), which are usually coupled with numerous sensitive detectors, have been extensively published and reviewed. 4,10−12 Chemical generation of volatile hydrides (CHG) coupled with atomic and mass spectrometric techniques represents one of the most important analytical tools for the determination and speciation of hydride-forming elements at trace and ultratrace levels.…”

Inorganic Arsenic Determination in Food: A Review of Analytical Proposals and Quality Assessment Over the Last Six Years

“…Chen et al 132 propose a method for selective separation of As(III) from As(V) based on adsorption on multi-wall carbon nanotubes functionalized with branched cationic polyethyleneimine (BPEI-MWNTs) and measurement by HG-AFS. Matoušek et al 133 develop a method for arsenic speciation based on selective HG-cryotrapping-ICP-MS, based on cryotrapping of arsines and desorption at their boiling points. Dados et al 134 propose a system to trap in situ arsenic hydrides previously generated using a nano-sized ceria-coated silica-iron oxide and final measurement of the slurry by inductively coupled plasma optical emission spectroscopy (ICPOES).…”