Colorimetric determination of arsenic

Vašák, V.; Šedivec, V.

doi:10.1135/cccc19530064

Cited by 15 publications

(2 citation statements)

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“…To our knowledge, no previous work has been published regarding the absorption characteristics obtained this way. Rather were the gases produced from precursors using specific reductants [15,26,30,36]. Sparging of AsH 3 under a nitrogen atmosphere resulted in the rapid formation of a deep red complex indicated by a broad absorption band with a maximum at 540 nm.…”

Section: Comparison Of Uv/vis-spectramentioning

confidence: 99%

“…Similar to the de-staining of Rhodamine-B upon reaction of As(III) with KIO 3 [12,13], the colourimetric silver diethyldithiocarbamate (AgDDTC) method is a compromise between field-test kits and expensive instrumental analytics. It is the most popular spectrophotometric method [14] and dates back to the work of Vašák and Šedivec in 1952 [15]. Since then, it has been continuously refined and modified with regard to different sample matrices [16][17][18][19], optimisation of the chromophoric [17,20,21] and hydride generation methods [22][23][24], the identification of interferences [17,[25][26][27][28] and As speciation [29][30][31][32].…”

Section: Introductionmentioning

confidence: 99%

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Overestimation of geogenic arsenic in landfill leachate: interference of humic and phosphinic acid in a commercial test kit

Brück

Glatthaar

Weigand

2014

International Journal of Environmental Analytical Chemistry

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Large-scale groundwater contamination by arsenic (As) requires economical yet reliable analytical procedures to monitor the quality of well water and the effluent of As elimination processes. The silver diethyldithiocarbamate (AgDDTC) method provides the basis of a series of colourimetric tests used as a compromise between semi-quantitative field-test kits and expensive instrumental analytics. This study aimed at understanding the significant As overestimation by the AgDDTC method observed in landfill leachate samples. Results of the AgDDTC test were up to threefold the levels obtained by reference analyses. Overestimation broadly agreed with the time course of chemical oxygen demand and total phosphorus in the leachate. We hypothesised that the interference was caused by reduced P species or humic acid (HA), respectively. To test this, As-AgDDTC determinations from As standards were conducted with phosphonic (H 3 PO 3 ) and phosphinic acid (H 3 PO 2 ) as well as two commercial HA as matrix components. While H 3 PO 3 showed no effect, H 3 PO 2 in concentrations of 0.06 to 28 mg P L −1 yielded As recoveries of up to 130%. This was probably due to the evolution of phosphine (PH 3 ) as suggested by the absorption spectra recorded after reacting pure PH 3 with AgDDTC in pyridine. The HA in concentrations of 0.6-320 mg dissolved organic carbon L −1 gave As recoveries of up to 600%, possibly due to a chromophoric reaction of volatile HA digestion products formed during the reduction step. Significant As overestimation in the presence of the above-named compounds may require pre-oxidation of the samples. To recognise interference effects, the acquisition of full absorbance spectra may be recommendable in lieu of fixed wavelength analyses.

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Section: Comparison Of Uv/vis-spectramentioning

confidence: 99%