Utilization of electrodeposition on a graphite probe modified with palladium in determination of lead by graphite furnace atomic absorption spectrometry in water and environmental samples

In this work a rapid and selective procedure for separation and preconcentration of lead (Pb2+) before determination by electrothermal atomic absorption spectrometry (ETAAS) was developed. The procedure is based on the electrodeposition on a graphite probe modified with palladium. The lead was deposited from acetate buffer solution at pH 5.5. Various parameters, such as pH of solutions, deposition potential, buffer concentration, stirrer speed, time of deposition and temperature program, were optimized. After optimization of the conditions, detection limit 17 ng L–1 by 3 σ, and enrichment factor 61 were achieved for 2 min electrodeposition time and improved as deposition time was increased. Linearity of calibration was kept between 0.05-0.50 μg L–1 with a correlation coefficient of 0.9979 and suitable precision, R.S.D. % = 5.1 (n = 8). Samples were digested completely in a closed microwave digestion system using only perchloric acid, and interference owing to various cations was also investigated. The procedure was successfully applied to determine the presence of lead in rice, radish, okra, onion and water samples.