A novel sampling strategy for metal ions determination in water: application to the determination of cadmium

• Sampling device for water sampling and sample treatment in a single step • Based on solid phase extraction, using a cationic exchange resin, Chelex 100 • Five-fold analyte enrichment • Reusable sampling device, up to 50 usages • Successful application for cadmium quantification in freshwaters This work proposes a novel, portable, and reusable device for in situ water sampling, sample preparation, and analyte enrichment in a single step. For this purpose, a commercial cationic exchange resin (Chelex 100), was used to obtain a solid-phase extraction column for cadmium (II) retention and enrichment. The optimization of key parameters such as sample volume, reagents concentration, and flow-rate, was performed to maximize cadmium retention and elution efficiency. The method was applied to real samples, and the results agreed with those obtained with reference methodologies, with no significant differences (< 10%). Additionally, recovery rates of 97.8 ± 3.5% were achieved. This method integrates, in one step, the sampling and sample preparation procedures and employs reusable devices, contributing to providing a sustainable solution for metal ions monitoring in aquatic environments.