Arsenic (As) compounds are widely used and have long been recognized as toxicants. Acute As exposure can give symptoms with rapid onset of headache, nausea and severe gastrointestinal irritation. The occurrence of arsenic in plants and animals generally reflects its accumulation from the environment [1,2]. The presence of As in drinking water has reached calamitous proportions in many parts of the world. Many analytical methods have been employed for determination of As; however, the development of sensitive and accurate methods for preconcentration and determination of trace amounts of As is necessary [3,4]. In this study, a simple and sensitive method for the determination of As in water samples was developed. The method is based on the formation of micro particles of Methyl Violet and Molybdoarsenate, which gives an apparently homogeneous blue color to the solution. The absorption of the excess dye gradually decreases due to its conversion to a colorless carbinol species under strongly acidic conditions [1-2]. As in the range of 0.5-100 ppb could be determined. The relative standard deviation for 15 determinations of 40 ppb As was 2.45% and the limit of detection was 0.15 ppb. The proposed method was applied to the determination of As in water samples with satisfactory results.
