%0 Journal Article
%T Determination of Arsenic in Drinking Water Samples by Electrothermal Atomic Absorption Spectrometry after Preconcentration Using the Biomass of Aspergillus niger Loaded on Activated Charcoal
%A Mohsen Shahlaei
%A Alireza Pourhossein
%J Journal of Chemistry
%D 2014
%I Hindawi Publishing Corporation
%R 10.1155/2014/912619
%X A simple, fast, and sensitive method for determination of total arsenic in drinking water sample by ETAAS after solid phase preconcentration has been developed. The dead biomass of A. niger loaded on activated charcoal has been applied as bioadsorbent for preconcentration step. The effects of parameters such as pH, type and concentration of eluent, biosorption time, sample volume, and effect of interfering ions have also been studied. Under the optimum condition, the enrichment factor of 10 for the analyte has been obtained. The accuracy of the method has been investigated by the recovery of spiked standards and the recovery percents between 99 and 102% have been achieved. Total amount of arsenic was determined by reducing As (V) to As (III) with potassium iodide (KI) and ascorbic acid in HCl solution. Under the optimum conditions, for 400£¿mL of drinking water samples, the detection limit (3¦Ò) and linear range were achieved 1£¿ng/mL and 5¨C100£¿ng/mL, respectively. The relative standard deviation for ten determinations of a spiked sample with concentration of 10£¿ng/mL As was 3.2%. 1. Introduction Arsenic is a toxic trace element widely distributed in nature. The malignant symptoms may appear even when trace arsenic is ingested. The toxicity mechanism of arsenic has been shown that it binds to enzymes, which are inhibited for functioning [1]. Arsenic is present in water, soils, rocks, and all living things (plants and animals); also, it is accumulative poison that affects all bodily systems [2¨C4]. Because of its high toxicity, it is of great importance to regularly monitor and recover arsenic from different samples such as natural waters. Recently, WHO prescribes a limit of 10£¿ng/mL for total As in drinking waters [5]. The analysis of such low levels demands highly sensitive techniques. Some analytical techniques have been used for trace determination of arsenic such as colorimetry [6, 7], atomic absorption spectrometry [7, 8], hydride generation system combined with atomic absorption spectrometry [9], inductively coupled plasma mass spectrometry [10, 11], and atomic fluorescence spectrometry [12]. Recently, electrothermal atomic absorption spectrometery has been extremely used as a powerful technique for determination of arsenic in various samples [13]. The results obtained by ETAAS show good sensitivity and low detection limits. But the sensitivity of analysis by ETAAS can decrease because of aging of graphite tube which is used as atomizer. Therefore in order to achieve accurate, sensitive and reliable results at ultratrace levels of As with ETAAS,
%U http://www.hindawi.com/journals/jchem/2014/912619/