Spectrophotometric determination of arsenic in soil samples using 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol (Br-PADAP)

Abstract

In this paper, a new, simple and sensitive method for arsenic determination in soil is proposed. This is based on the reduction of silver (I) and iron (III) ions by arsine followed by a complexation reaction of iron (II) with the spectrophotometric reagent Br-PADAP 2-(5-bromo-2-pyridylazo)-5-di-ethylaminophenol. Arsenic determination with a Sandell's sensitivity of 3.1 10-4 cm-2, linear range from 0.1 µg ml-1 to 2.0 µg ml-1 (r560 = 0.9995), molar absorptivity of 2.45 10(5) l mol-1 cm-1 and a concentration detection limit of 1.4 ng ml-1 (3s) were obtained using a 10 ml sample volume. Selectivity was increased with the use of EDTA as a masking agent. The proposed method was applied for arsenic determination in the presence of several ions amounts in digested soil samples. The results revealed that antimony (III), mercury (II), germanium (IV), platinum (IV) interferes at all analyzed proportions. The interferences can be easily removed by the use of EDTA. Precision and accuracy obtained were satisfactory with a R.S.D. < 5 %. Recovery of arsenic in soil samples varied from 95.55 to 102.70 % with a mean of 99.63 %. These results demonstrated that the proposed method is applicable for arsenic analysis in different soil samples.

Metal contamination in traditionally used Medicinal plants: a serious threat in Murshidabad district, West Bengal, India

“…Another part of each soil sample was digested with di-acid mixture for analysis of arsenic concentration by SDDC method (Pereira et al, 2008;APHA, 1998).…”

The Recent Advances and Applications of Arsenic Speciation in Water

“…CPE is a powerful technique for separation and preconcentration of metal ions that can easily be adapted for AAS to improve the detection limit and selectivity of determinations, some drawbacks inherent in chromatographic separations can be overcome. This method has been applied for as preconcentration by using molybdate [23] , ammonium pyrolidine dithiocarbamate [24] ,o,o-diethyldithiophosphate [25] ,2-(5-bromo-2-pyridylazo)-5-diethylaminophenol( Br-PADAP) [26] and ammonium pyrolidine dithiocarbamate [27] as chelating agents. Ulusoy et al [28] has successfully been employed for the preconcentration of ultra-trace As species in aqueous samples prior to HGAAS.…”