Cloud point extractors for simultaneous determination of Pd and Pt in water samples by ICP OES with multivariate optimisation

Abstract

- Palladium and platinum preconcentration in water samples prior to ICP OES determination. - Friendly solvents extraction for noble's metals investigation in aquatic compartments. - The use of the labilising agents for reduction the inertia of the chlorocomplexes in CPE methods. - Multivariate optimisation in cloud point extraction. Catalysts used in the combustion process inside vehicles, palladium (Pd) and platinum (Pt), can be released to the atmosphere and deposited in aquatic environments. Thus, a simple and environmentally friendly method was developed for simultaneous Pd and Pt determination by ICP OES in aqueous samples. Cloud point extractions (CPE) combined with a factorial design were employed to achieve method accuracy. The extraction was facilitated based on the interaction between a reducing (labilising) agent in hydrochloric acid medium together with the analytes. The cloud point solution (CPS) was composed of the non-ionic surfactant (Triton X-114), the chelating agent 2-mercaptobenzothiazole (2-MBT), the labilising agent tin chloride (SnCl 2 ) or potassium iodide (KI) as well as HCl. The analytical curves were linear in the range of 5–100 μg L −1 with detection limits of 0.525 and 0.752 μg L −1 for Pd and Pt, respectively. Factorial design, considering the concentration of Triton X-114, 2-MBT, HCl, SnCl 2 and KI, was used to optimise the analytical protocol. The proposed method was successfully applied in samples of tap, fresh, and saline waters.