Selective reduction of arsenic species by hydride generation - atomic absorption spectrometry. Part 2 - sample storage and arsenic determination in natural waters

Abstract

Arsênio total, As(III), As(V) e ácido dimetilarsínico (DMA) foram determinados seletivamente em águas naturais pela técnica da geração de hidretos -espectrometria de absorção atômica, em diferentes meios de redução. Para as amostras de água de rio investigadas os resultados mostraram ser arsenato a forma arsenical predominante. Os limites de detecção encontrados para As(III) (tampão citrato), As(III) + DMA (ácido acético ) e As(III) + As(V) (ácido clorídrico) foram, respectivamente, 0.6, 1.1 e 0.5 mg As L -1 . O estudo da estabilidade das formas arsenicais em amostras de águas naturais revelou serem os próprios meios reacionais convenientes para uma preservação adequada das amostras.Total arsenic, arsenite, arsinate and dimethylarsinic acid (DMA) were selectively determined in natural waters by hydride generation -atomic absorption spectrometry, using sodium tetrahydroborate(III) as reductant but in different reduction media. River water samples from the north region of Paraná State, Brazil, were analysed and showed arsenate as the principal arsenical form. Detection limits found for As(III) (citrate buffer), As(III) + DMA (acetic acid) and As(III) + As(V) (hydrochloric acid) were 0.6, 1.1 and 0.5 mg As L -1 , respectively. Sample storage on the proper reaction media revealed to be a useful way to preserve the water sample.

Speciation Analysis of Trace Inorganic Arsenic in Dietary Supplements by Slurry Sampling Hydride Generation Atomic Absorption Spectrometry

“…Otherwise, selective medium reactions were investigated for selectively generating the hydrides of each arsenic species (Bermejo-Barrera et al 1998;Quináia and Rollemberg 2001). Total inorganic arsenic [As(III) and As (V)] content can be determined using KBH 4 under higher HCl acidity after prereduction with KI, and DMA could not be determined under the same conditions.…”

Non-chromatographic hydride generation atomic spectrometric techniques for the speciation analysis of arsenic, antimony, selenium, and tellurium in water samples—a review

“…The use of L-cysteine gained popularity as a prereductant, and many procedures have included its use for As speciation analysis. Following the method of Anderson et al [105], several articles were published on arsenic speciation analysis utilizing different acids, buffers, and redox media to determine inorganic [109][110][111] and methylated species [61][62][63][64][112][113][114][115][116][117]. Typical procedures include the work of Torralba et al [112,113], Yano et al [114], Rude and Puchelt [115], Quinaia et al [116], and Shraim et al [64,117].…”

Advances in atomic emission, absorption and fluorescence spectrometry and related techniques

“…They suggested two mechanisms for the generation of arsines: (a) at low acid concentrations the thiolate As complexes in the 31 state react rapidly with borohydride, and (b) at high acid concentrations, arsines are generated by the reaction with nascent hydrogen produced by the decomposition of borohydride. A somewhat similar approach was adopted by Quinaia and Rollember 136 to speciate As by HG-AAS. In citrate buffer only As III was determined; in acetic acid both As III and DMA were measured, and in HCl both As III and As V were determined.…”