A new procedure for ultratrace determination of lead in a single phase water-ethanol system by fluorescence measurements

Lead is cumulative poision[1] that enters the body from lead water pipes, and lead based paints. Lead pollution is a serious danger to the environment and human health[2-3]. Lead intake causes many fatal diseases including disfunction of renal, blood and neurological systems. Lead (II) easily deposits in blood,kidney, reproductive system, nervous system and brain and cause lead poisoning[4]. Even low levels of lead in children cause brain and neurodevelopmental deseases[5]. Hence the determination of trace amounts of lead is important for environmental monitoring and this demands sensitive and accurate determination of lead. In this work a new procedure was found for determination of lead(II) in aqueous ethanol system. The proposed method is based on the complex formation between of lead(II) and dithizone. The parameters such as pH, cocentration of dithizone, and solvent ratio was optimized at pH 6, concentration of dithizone 1.16×10-5M , and solvent ratio( 50 % ethanol by volume0. The fluorescence intensity (excitation/ emission maxima 450/670) of Pb-Dtz complex was proportional to the concentration of pb 2+ ions in the range of 2.63nm-0.26µm with linear correlation coefficient( R 2 = 0.993) and LOD(S/N=3) of 0.5ppb and %RSD = 3. Fig 1. Fluorescence intensity graph in the different concentration of Pb2+