Investigation of the new sorption preconcentration systems for determination of noble metals in rocks by inductively coupled plasma–mass spectrometry

• Six HP and Stirosorb sorbents for NMs' preconcentration were used for the first time.
• Degree of polymer network crosslinking plays a critical role in the sorption efficiency.
• The conditions of reversible extraction of Ru, Pd, Pt, Au on Stirosorb-514 were found.
• The interferences from Cu and Ni in ICP-MS analysis of NMs are insignificant.

The reversible sorption preconcentration of noble metals (NMs) prior to their determination by inductively coupled plasma–mass spectrometry (ICP-MS) was investigated. Six new hypercrosslinked polystyrene sorbents were tested. The dependence of the degree of NMs sorption on the average degree of polymer network crosslinking and pore diameters was investigated. It was found that sorbents HP-100/6, HP-300/6 and HP-500/6 have low efficiency of NMs chlorocomplexes extraction. Among Stirosorb sorbents (Stirosorb-2, Stirosorb-514 and Stirosorb-584) the highest efficiency of the extraction of NMs’ chlorocomplexes has Stirosorb-514. Tributylamine (TBA), N-methylbenzylamine (MBA), N,N-dimethylbenzylamine (DMBA), N,N-dibenzylmetylamine (DBMA) were studied as the reagents for extraction of Ru, Rh, Pd, Ir, Pt and Au chlorocomplexes from hydrochloric acid solutions in the form of ion associates by reversed-phase mechanism. The reversible quantitative extraction of Ru, Pd, Pt and Au in system Stirosorb-514 – TBA – 1 M HCl in ethanol as eluent was achieved. It was found that resulting eluates do not contain matrix components which may cause spectral interferences on the stage of NMs determination by ICP-MS. The found scheme of NMs reversible sorption was validated by the analysis of certified reference materials of basic and ultrabasic rocks GPt-5, GPt-6 and SARM-7. Good agreement between the measured NMs concentrations and the certified values was demonstrated. The achieved limits of detection for Ru, Pd, Pt and Au vary within 10−8–10−7 wt% range.

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