Evaluation of Cadmium (II) and Lead (II) in marine soil in Benghazi city using Atomic Absorption Spectroscopy

This article presents a new approach to measure the concentrations of lead and cadmium in soil marine samples. The technique involves a two-step process: first, the samples are pre-concentrated using liquid-liquid extraction, and then atomic fluorescence spectrometry is used for analysis. In this process, dithizone is used as the chelating agent. During the procedure, a complex is formed between lead and cadmium with dithizone. The researchers also investigated important factors that may affect the efficiency of the extraction, such as pH of the sample and shaking duration.The results demonstrated that the extraction process yielded optimal results within a pH range of 7 to 9, and the ideal duration of shaking was between 10 to 30 minutes. Through stoichiometry analysis, it was determined that the most probable structure of the extracted ion pair complex consisted of one metal ion bonded to two ligand molecules (1M+2:2HDZ-). The influence of organic solvents on the extraction process showed that the distribution ratio (D) for extraction increased with a decrease in dielectric constant. Particularly, carbon tetrachloride demonstrated a higher distribution ratio (D), possibly due to its lower dielectric constant, which aids in the disruption of hydration shell around metal cations (Cd and Pb), allowing for enhanced coordination between the ligand molecules and metal cations. A previously described method for analyzing Cd and Pb in marine soil was adapted for this study.