Speciation of arsenic using sulfur containing ligand and cotton wool by ICP-OES

Abstract

This research aimed to develop a method for speciation of arsenic species including As(III) and As(V) in environmental samples. Cotton wool and sulfur containing ligands including ammonium pyrrolidinedithiocarbarmate (APDC), L–cysteine and diethyldithiocarbamic acid were used in a solid phase extraction and determination of arsenic by using inductively coupled plasma optical emission spectrometry. The separation parameters were studied including pH, ligand concentration, cotton amount, type of eluents and flow rate. It was found that at pH 2, 0.1% APDC concentration and 0.5 g of cotton, As(III) could form complex with APDC (As(III) – APDC) and was separated from As(V) by using cotton column. The adsorption percentage was around 90%. Then As(III) was eluted by using 5 mL of 4 M HNO3, 4 M HCl and 0.5 M H2O2 at a ratio of 1:1:1 as eluent. The proposed method was then used to perform a speciation analysis of arsenic in solutions containing As(III) and As(V) in the range of 10 – 1000 μg L-1. The results showed good recoveries of both arsenic species at 83 - 118% with acceptable relative standard deviation (%RSD). The proposed method was applied for arsenic speciation in environmental water samples. The results showed good recoveries and %RSD.