In the present work, the analytical performance of a methodology based on a preconcentration using activated thin layers followed by high-energy polarised beam energy-dispersive XRF spectrometry (HE-P-EDXRF) for the determination of trace amounts of Cd in saline solutions is presented. Linear calibration curves were obtained over the range 5-8000 μg L-1 of Cd. When comparing the developed method to the direct analysis of Cd in sea water, the detection limits were improved by several orders of magnitude, with values of 2.25 μg L-1 (Al2O3 target) and 0.075 μg L -1 (CsI target), respectively. The accuracy was checked by analyzing spiked natural sea water at Cd concentrations of 20, 100 and 600 μg L -1 and results were compared to those obtained with anodic stripping voltametry and no significant differences at the 95% confidence level were found. The method has a good reproducibility over the investigated period of time and the precision of the method was better than 10%

This research has been developed in the framework of the Spanish National Research Programme (Projects: CGL2004-05963-C04/HID and CGL2007-66861-C4)