DETERMINATION OF LEAD IN HARAMAYA UNIVERSITY TAP WATER WITH DISPERSIVE LIQUID-LIQUID MICROEXTRACTION USING UV-VISIBLE SPECTROPHOTOMETER

Abstract

The need for highly reliable methods for the determination of trace and ultratrace elements has been recognized in analytical chemistry and environmental science. A powerful microextraction technique was used for the detection of the lead trace amounts in water samples using the dispersive liquid–liquid microextraction (DLLME), followed by UV-Visible spectrophotometery. In this microextraction technique, a mixture of 5 mL methanol (disperser solvent), containing 35 𝜇L carbon tetrachloride (extraction solvent) and 5 mL APDC (chelating agent), was rapidly injected by syringe into the 10 mL water sample, spiked with lead. In this process, the lead ions reacted with the chelating agent and were extracted into the fine droplets of CCl4.After centrifugation, the fine CCl4 droplets were sedimentedat the bottom of the conical test tube. The next step was evaluating parameters affecting DLLME, such asthe type and the volume of the extraction solvent, the type and the volume of the disperser solvent, pH, the chelating agent concentration, the extraction time, centrifugation time and the interfering ion. The relative lead recoveries in tap water sample at the spiking level of 0.071 ppm before spiking, 0.169 ppm after spiking and 0.1 ppm concentration of added amount. The percent recovery value was 98%.