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Determination of arsenic species in environmental samples

Khalid H Al-Assaf, University of Massachusetts Amherst

Abstract

A method was developed for preconcentration, separation, and determination of arsenic species [As(III), As(V), DMA, and MMA] in water samples by flow injection solid phase extraction hydride generation atomic absorption spectrometry. Competing anion interferences were minimized by employing two anion-exchange columns in series. The method was successfully applied for the determination of trace concentrations in various water samples spiked with a mixture of arsenic species. ^ A new method was developed for the determination of ultra-trace amounts of As(III) and As(V) by flow injection solid phase extraction hydride generation atomic absorption spectrometry with tetrahydroborate immobilized on an anion-exchange substrate. The method offers several advantages including simplicity, sensitivity improvement, arsenic speciation, cost reduction and less waste generation compared to the conventional hydride generation AAS method. The method was successfully applied to the determination of As(III) and As(V) in different kinds of environmental water samples including well water, lake water, tap water, spring water, and sea water. ^ A new method was developed for the determination of As(III), As(V), DMA and MMA by high performance liquid chromatography hydride generation inductively coupled plasma optical emission spectrometry. The new multimode sample introduction system (MSIS) was employed instead of a conventional gas-liquid separator. The separation was achieved with good resolution and detection limits by using an anion-exchange column, either an IonPac AS10 or an Alltech Anion HC column. ^ The extraction of arsenic species from soils was significantly improved with a sequential extraction procedure. Arsenic species extracted were successfully separated and determined by high performance liquid chromatography hydride generation inductively coupled plasma optical emission spectrometry with the MSIS. No significant changes in the arsenic species were observed during the extraction. ^ A method was developed for improving the detection of the Hach test kits. Solid phase extraction was used for the preconcentration of arsenic in water samples prior to testing by the Hach kit. The color intensity for all concentrations including those close to 10 μg l-1 was increased. The method was successfully applied to environmental water samples spiked with low arsenic concentrations. ^

Subject Area

Analytical chemistry

Recommended Citation

Al-Assaf, Khalid H, "Determination of arsenic species in environmental samples" (2007). Doctoral Dissertations Available from Proquest. AAI3254933.
http://scholarworks.umass.edu/dissertations/AAI3254933

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