Solid-phase extraction to preconcentrate trace amounts of palladium using ZnO nanoparticles

The determination of palladium in environmental samples is difficult because of the high concentration of interfering matrix components and its low content in the most of samples [1]. To solve these problems, preconcentration and separation techniques have been often exploited [2]. In this work, a simple method based on solid phase extraction applying zinc oxide (ZnO) nanoparticles and atomic absorption spectrometry was developed for the trace amount determination of palladium (II) in aquatic samples. ZnO nanoparticles were prepared by dissolution–reprecipitation of micro-sized ZnO powder [3] and after characterization by SEM, IR and XRD techniques were applied for the solid phase extraction of palladium ions from aqueous solutions. Important parameters influencing the extraction and desorption process including sample pH, desorption solvent and its volume, extraction and desorption time were optimized. Under optimal conditions, a preconcentration factor of 143 was obtained. The calibration graph showed linearity in the range of 2.49 -70.0 μg L-1 of palladium with correlation coefficient of 0.9980. Detection limit based on the 3Sb criterion was 0.74 μg L-1 and relative standard deviation for six replicate measurements was found to be 3.8%. (n = 6). The developed method was successfully applied to real water samples while the recovery percentages obtained for the spiked water samples were from 93.5 to 101.2 %.