Ultratrace Determination of Cd (II) in Water, Salt, Environmental, Alloy, and Biological Samples by Liquid-Liquid Extraction Followed by Inductively Coupled Plasma Mass Spectrometry Technique.

RATIONALE: Cadmium is a highly toxic heavy metal associated with severe environmental and health risks, making its precise quantification in complex matrices critical. Inductively coupled plasma mass spectrometry (ICP-MS) is one of the most powerful tools for trace metal analysis due to its exceptional sensitivity, selectivity, and multielement capability. However, accurate detection often requires effective preconcentration and matrix elimination strategies.

METHOD: A liquid-liquid extraction procedure was developed using N,N'-diphenyl sebacoyl dihydroxamic acid (DPSDHA) as a selective complexing ligand for cadmium. The Cd-DPSDHA binary complex formed at pH 9.5 was extracted into dichloromethane, effectively preconcentrating cadmium and minimizing matrix interference prior to ICP-MS measurement. The optimized conditions ensured maximum recovery and stability of the analyte, thereby improving detection limits and analytical precision.

RESULT: Coupling the DPSDHA extraction with ICP-MS enabled trace-level determination of cadmium with excellent sensitivity and reproducibility. The method exhibited a wide linear dynamic range, low detection limits, and strong resistance to matrix interferences, ensuring accurate quantification in complex samples. Application to water, alloy, environmental, and biological samples yielded accurate results, which were consistent with certified reference values.

CONCLUSIONS: The combination of selective DPSDHA-based extraction with ICP-MS provides a robust, highly sensitive approach for cadmium determination in diverse sample matrices. This methodology enhances detection accuracy by reducing matrix effects, making it well-suited for environmental monitoring, industrial quality control, and biological studies where trace-level cadmium analysis is essential.