Preliminary screening method for the determination of inorganic arsenic in urine

A simple and rapid method was developed for the routine determination and classification of inorganic arsenic based on its clinical and forensic properties. Inorganic arsenic was isolated from urine by using copper granules, which was then made to react with ammonium molybdate in order to detect its presence with the naked eye. Based on studies of extraction and reaction conditions, e.g., reaction temperature and time, a colorimetric screening method was established. The reaction mixture was measured by a spectrophotometer, and there was linearity from 0.05 to 2.0microg/ml and the correlation coefficients of the calibration curves were greater than 0.99. The coefficients of intra-day variation at 0.2 and 2.0microg/ml of inorganic arsenic in urine were 9.6 and 4.2%, respectively (n=5). The minimum detectable level in urine is 0.03microg/ml, and it is possible to detect the lowest level of poisoning according to the published reports. The proposed method was applied to a poisoning case wherein the patient ingested NEOARSEN BLACK with alcohol, which contained 45% of arsenic trioxide. This method produced positive results in all the urine samples tested, and this method is useful for the screening of inorganic arsenic based on its clinical properties because it enables the detection of inorganic arsenic in urine without expensive equipment.