Prereduction of arsenic(V) to arsenic(III), enhancement of the signal, and reduction of interferences by L-cysteine in the determination of arsenic by hydride generation

Chen, Hengwu.; Brindle, Ian D.; Le, X. C.

doi:10.1021/ac00030a018

Cited by 145 publications

(71 citation statements)

References 42 publications

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“…At the concentrations below 1 % (m/v), i.e. 0.057 M, longer time may be needed to complete the process of pre-reduction of all arsenicals [16,22], however, this was not tested in this study. 2 % (m/v) of L-cys was used for further experiments.…”

Section: Resultsmentioning

confidence: 99%

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On-line pre-reduction of pentavalent arsenicals by thioglycolic acid for speciation analysis by selective hydride generation–cryotrapping–atomic absorption spectrometry

Musil

Matoušek

2008

Spectrochimica Acta Part B: Atomic Spectroscopy

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An improvement of current method of selective hydride generation based on pre-reduction for differentiation of tri-and pentavalent arsenicals is described, applied for the oxidation state specific speciation analysis of inorganic, mono-, di-and trimethylated arsenicals with minimum sample pretreatment using atomic absorption spectrometry with the multiatomizer. The preconcentration and separation of arsine, methylarsine, dimethylarsine and trimethylarsine is then carried out by means of cryotrapping. Presented study shows that 2% (m/v) L-cysteine hydrochloride monohydrate (L-cys) currently used for off-line pre-reduction of pentavalent arsenicals can be substituted with 1% (m/v) thioglycolic acid (TGA). Much faster pre-reduction of pentavalent arsenicals at 25°C with equal sensitivities as in the case of L-cys has been achieved with TGA. A setup for on-line prereduction by TGA has been optimized, with the application of segmented flow analysis for suppression of axial dispersion in the pre-reduction coil. Standard calibrations measured with or without on-line pre-reduction indicate uniform and equal sensitivities for all As forms. The possibility of standardization by water standards of single species (e.g. iAs(III)) for quantification of all other As forms in urine is demonstrated in the recovery study. Limits of detection were 100 ng·l −1 for iAs (III), 135 ng·l −1 for iAs(V) and 30 to 50 ng·l −1 for methylated arsenicals.

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Section: Resultsmentioning

confidence: 99%

“…Due to low stability and neccessity of high concentration of KI and HCl for reaching complete pre-reduction, agents with -SH group, namely L-cysteine (L-cys) are more popular nowadays [13,16,[21][22][23][24]. These agents reduce pentavalent arsenicals to trivalent and react with trivalent arsenicals forming arsinothiol derivates.…”

Section: Introductionmentioning

confidence: 99%

On-line pre-reduction of pentavalent arsenicals by thioglycolic acid for speciation analysis by selective hydride generation–cryotrapping–atomic absorption spectrometry

Musil

Matoušek

2008

Spectrochimica Acta Part B: Atomic Spectroscopy

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“…The enhancing effect of L-cysteine on HG of As compounds is well established [13,[25][26][27][28][29]. L-cysteine reduces pentavalent arsenicals to trivalency and reacts with trivalent arsenicals, forming arsinothiol derivatives [26,27,30].…”

Section: Introductionmentioning

confidence: 99%

Oxidation state specific generation of arsines from methylated arsenicals based on l-cysteine treatment in buffered media for speciation analysis by hydride generation-automated cryotrapping-gas chromatography-atomic absorption spectrometry with the multiatomizer

Matoušek

Hernández-Zavala

Svoboda

et al. 2008

Spectrochimica Acta Part B: Atomic Spectroscopy

148

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An automated system for hydride generation -cryotrapping-gas chromatography -atomic absorption spectrometry with the multiatomizer is described. Arsines are preconcentrated and separated in a Chromosorb filled U-tube. An automated cryotrapping unit, employing nitrogen gas formed upon heating in the detection phase for the displacement of the cooling liquid nitrogen, has been developed. The conditions for separation of arsines in a Chromosorb filled U-tube have been optimized. A complete separation of signals from arsine, methylarsine, dimethylarsine, and trimethylarsine has been achieved within a 60 s reading window. The limits of detection for methylated arsenicals tested were 4 ng l −1 . Selective hydride generation is applied for the oxidation state specific speciation analysis of inorganic and methylated arsenicals. The arsines are generated either exclusively from trivalent or from both tri-and pentavalent inorganic and methylated arsenicals depending on the presence of L-cysteine as a prereductant and/or reaction modifier. A TRIS buffer reaction medium is proposed to overcome narrow optimum concentration range observed for the L-cysteine modified reaction in HCl medium. The system provides uniform peak area sensitivity for all As species. Consequently, the calibration with a single form of As is possible. This method permits a highthroughput speciation analysis of metabolites of inorganic arsenic in relatively complex biological matrices such as cell culture systems without sample pretreatment, thus preserving the distribution of tri-and pentavalent species.

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“…Além disso, quando há concentrações consideráveis de arsênio inorgânico na amostra ou quando estas são de interesse, a pré-redução pode ser realizada usando compostos que contenham o grupo tiol, como a L-cisteína e o tioglicerol, permitindo a obtenção de um único sinal para todas as espécies de arsênio em solução nas mesmas condições de acidez. 10,11 Outra técnica baseia-se na formação seletiva de arsina pelas diferentes espécies de As através da variação do pH e das concentrações do pré-redutor (L-cisteína) e do redutor (NaBH 4 ) envolvidos na reação de formação de arsina, sem a necessidade de pré-concentração e separação das espécies por cromatografia (HPLC) ou por trapeamento criogênico. 12 Nesta situação, as concentrações das quatro espécies mais comuns de As (As(III), As(V), MMA, DMA) de uma amostra são determinadas através de quatro determinações na amostra.…”

Section: Introductionunclassified

Estudo da especiação de arsênio inorgânico e determinação de arsênio total no monitoramento ambiental da qualidade de águas subterrâneas

Borba¹,

Puga²,

Figueiredo³

et al. 2009

Quím. Nova

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Estudo da EspEciação dE arsênio inorgânico E dEtErminação dE arsênio total noRecebido em 18/6/08; aceito em 24/10/08; publicado na web 12/2/09 DETERMINATION OF TOTAL As AND INORGANIC ARSENIC SPECIES FOR THE ENVIRONMENTAL QUALITY MONITORING OF GROUNDWATERS. This work reports an alternative, fast and robust method, for the determination of total As, As(III) and As(V) by HG-AAS without the use of prereductants. The method is based on the different rates of arsine formation of the inorganic As species and the effect of As(III) in the signal obtained for total As. Groundwater and mineral spiked waters were used to sample preservation evaluation. The method was validated by the determination of As in SRM 1640 and used in the determination of total As and its inorganic species in groundwater samples collected from mines in the Iron Quadrangle -MG.

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Prereduction of arsenic(V) to arsenic(III), enhancement of the signal, and reduction of interferences by L-cysteine in the determination of arsenic by hydride generation

Cited by 145 publications

References 42 publications

On-line pre-reduction of pentavalent arsenicals by thioglycolic acid for speciation analysis by selective hydride generation–cryotrapping–atomic absorption spectrometry

On-line pre-reduction of pentavalent arsenicals by thioglycolic acid for speciation analysis by selective hydride generation–cryotrapping–atomic absorption spectrometry

Oxidation state specific generation of arsines from methylated arsenicals based on l-cysteine treatment in buffered media for speciation analysis by hydride generation-automated cryotrapping-gas chromatography-atomic absorption spectrometry with the multiatomizer

Estudo da especiação de arsênio inorgânico e determinação de arsênio total no monitoramento ambiental da qualidade de águas subterrâneas

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