engleski

Determination of arsenic species in liquid samples by EDXRF method

EDXRF is commonly used method for simultaneous trace element analyses of wide range of metals in complex environmental samples. Although, this method was used for bulk composition determination only, our intention was to develop appropriate procedure for trace element speciation followed by determination of the concentration of each specie by EDXRF system since toxicological behaviour and biochemical activity of the elements highly depends on their chemical form. This paper refers to the analyses of arsenic species by EDXRF method. A simple procedure for determination of As(III) and total arsenic in liquid samples via preconcentration with ammonium pyrrolidinedithiocarmbamate (APDC) and determination by EDXRF was described. The effect of pH in the range of 0-14 on the recovery of As(III) and As(V) has been investigated. The influence of organic matter and carbonate ions on the recovery of As(III) over whole pH range was also tested in order to simulate condition occurring in natural waters that usually contain certain amount of dissolved organic matter and carbonate species. It was determined that As(V) do not forming complex with APDC over whole pH range and As(III) is forming with maximum recovery on pH 0.5 which make possible to separate these two species. Concentration of total arsenic was determined as As(III) after reduction of As(V) to As(III). Method was tested on real environmental samples and compared with the results obtained for the same samples by ICPMS.

As(III) ; As(V) ; preconcentration ; EDXRF ;

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