Development of Spectrophotometric method for detection of trace of lead in aqueous ethanol system without using a preconcentration step

Lead is in focus of analytical chemists for a very long time due to its toxicity and its widespread use as a material in a variety of application including water piping, soldering, the printing industry, ballast, shielding, bullets, batteries, additive in gasoline pigment, and many others[1]. Naturally, The preconcentration steps slow the analytical process , which is a drawback when a large number of samples are to be analyzed. UV-Visible spectrophotometry employ less expensive instrumentation and is more suitable for automation of analytical procedures.[2]A modification of the dithizone Spectrophotometric method for determination of lead has been developed in this work by working in an aqueous ethanol system(80% ethanol by volume) and exraction and any Preconcentration step is avoided. The complex formation of lead in aqueous ethanol system with dithizone was completed rapidly at room temperature. The average molar absorption coefficient was found to be 1.16×10 7 L mol-1 cm-1. Two linear calibration graphs where obtained for 0.1-1 mg/L and 1-10 mg/L of pb(II). The interferance from over 20 cations , anions has been studied at 3 mg/L of pb(II). The maximum absorbance were observed in the pH 11 and in λmax 500nm. The standard deviation and %RSD of the method for ten determination of 3 mg/L of pb(II) is 0.00988 and 1.2% . This cost-effective sensing system allows for rapid and facile determination of pb(II) ions in aqueous sample.