Preconcentration/Separation of Palladium in Geological and Environmental Samples Based on Ionic Liquid Prior to the Determination by Flame Atomic Absorption Spectrometry

A simple and environmentally friendly method was developed for the preconcentration, separation, and determination of palladium (NOD) in geological and environmental samples. Room temperature ionic liquid (RTEL), 1-butyl-3-methylimidazolium hexafuorophosphate ([C4MIM][PF6]), was used for Pd(II) preconcentradon and diethyldithiocarbamate (DDTC) was used as the chelating agent for extraction. The DDTC complex was extracted into the ionic liquid phase. Subsequently, Pd(II) was back-extracted from the organic phase into 1 mL of 6M nitric acid solution and analyzed by flame atomic absorption spectrometry (FAAS). The parameters influencing the extraction and determination of Pd(R), such as pH, concentration of chelating agent, extraction time and temperature, amount of ionic liquid, ionic strength, and coexisting ions were investigated and optimized. Under the optimized experimental conditions, an enhancement factor of 29 was achieved with a 30-mL sample. The limit of detection (30) was 2.2 ng mL(-1), and the relative standard deviation (RSD) was 3.7% for 7 replicates. The method was successfully validated by analyzing palladium in the certified reference material and in environmental samples with satisfactory results.