Combination of a magnetic ionic liquid and magnetic particles for the determination of Pb(II) and Sn(IV) using electrothermal atomic absorption spectrometry

A procedure for the determination of traces of lead and tin by electrothermal atomic absorption spectrometry (ETAAS) after complexation with diethyl dithiophosphate and preconcentration by using a microextraction stage with a magnetic ionic liquid (MIL) supported by ferrite particles is presented. After complexation, the analytes are extracted into the ferrite-supported MIL, the solid particles acting as a carrier to facilitate the separation with a magnet. The analytes are released by treating with acetonitrile and the resulting liquid phase is sampled for the ETAAS measurement. The optimal experimental conditions such as pH, appropriate complexing agent, volumes and doses of all reagents used in the procedure are studied to achieve complete separation of both species. Enrichment factors of 195 and 165 and detection limits of 25 and 72 ng L-1 are obtained for Pb and Sn, respectively. The reliability of the procedure is checked by analyzing six certified reference materials and applied to water samples of different origin, the results being in addition confirmed by standard additions (recoveries 97 +/- 7% in all cases).