Speciation analysis of inorganic arsenic in water samples using thiol-ligand and cotton fibres followed by ICP-OES determination

ABSTRACTThis research aimed to develop a method for the speciation analysis of arsenic species, including As(III) and As(V) in environmental samples. Cotton fibres and thiol-ligands, including ammonium pyrrolidine dithiocarbamate (APDC), L-cysteine, and diethyldithiocarbamic acid (DDTC), were used as a simple solid phase extraction (SPE) followed by arsenic determination using inductively coupled plasma optical emission spectrometry (ICP-OES). The separation parameters were thoroughly investigated, including pH, thiol-ligand concentration, cotton fibre amount, type of eluents, and flow rate. It was found that As(III) could be efficiently separated from As(V) by using a column containing 0.5 g cotton fibres and 0.1% APDC under pH 2. As(III) was then eluted using 5 mL of mixed solvents of 4 M HNO3, 4 M HCl, and 0.5 M H2O2 (1:1:1 v/v). The method was then used to perform a speciation analysis of arsenic in model solutions with As(III) and As(V) concentrations ranging from 10–1000 μg/L. The results showed good recoveries of both arsenic species at 80–120% with a satisfactory percentage relative standard deviation (%RSD). The developed method was subsequently applied for arsenic speciation analysis in the environmental samples, including natural and wastewater samples.KEYWORDS: Arsenicspeciation analysissolid phase extractioncotton fibresAPDC AcknowledgmentsThe success of this research can be attributed to the Environmental Analysis Research Unit (EARU), Department of Chemistry, Faculty of Science, Chulalongkorn University.Disclosure statementNo potential conflict of interest was reported by the author(s).Supplementary materialSupplemental data for this article can be accessed online at https://doi.org/10.1080/03067319.2023.2258069.