Analysis of trace cadmium in the environment

Cadmium is one of the most ecotoxic metals. A Spanish and Belgian research group led by Dr. M. Hidalgo (University of Girona, Spain) has recently reported the determination of trace Cd in complex environmental liquid samples. The method employed is basically a combination of a pre-concentration technique and Cd Kα XRF analysis with a high-energy polarized beam (PANalytical Epsilon 5 with a Gd tube, 100kV-6mA, and a Ge detector). In order to collect trace Cd effectively, the research group used Aliquat 336 (trademark of Cognis Corp.), which is tricaprylmethylammonium chloride (C₂₅H₅₄ClN), as an extractant. The typical detection limit is 0.7 μg/L, and the accuracy was investigated by using spiked seawater samples and a synthetic water sample containing, besides Cd, high amounts of other metal pollutants such as Ni, Cu, and Pb. For more information, see the paper, "High-Energy Polarized-Beam Energy-Dispersive X-ray Fluorescence Analysis Combined with Activated Thin Layers for Cadmium Determination at Trace Levels in Complex Environmental Liquid Samples", E. Margui et al., Anal. Chem., 80, 2357 (2008).