Extraction and pre-concentration of platinum and palladium from microwave-digested road dust via ion exchanging mesoporous silica microparticles prior to their quantification by quadrupole ICP-MS

Abstract

We report on the use of mesoporous silica microparticles (μPs) functionalized with quarternary amino groups for the isolation of platinum and palladium tetrachloro complexes from aqueous road dust digests. The μPs have a size ranging from 450 to 850 nm and are suspended directly in the aqueous digests, upon which the anionic Pt and Pd complexes are retained on the cationic surface. Subsequently, the μPs are separated by centrifugation. Elements that cause spectral interferences in ICP-MS determination of Pt and Pd can be quantitatively removed by adding fresh 0.240 mol L−1 HCl to the μPs and by repeating the centrifugation step. The analyte-loaded μPs are then dissolved in 0.1 mL of 2 mol L−1 HF, diluted to 2 mL, and the solutions thus obtained are analyzed by quadrupole ICP-MS. This method avoids analyte elution from the sorbent. This “dispersed particle extraction” approach yielded a run-to-run relative standard deviation ≤ 5 % for Pt and ≤ 4 % for Pd (at 0.1 ng mL−1, n = 4 road dust digests). Method detection limits (expressed as concentrations in the dust samples) are 2 and 1 ng g−1 for Pt and Pd, respectively. The method was validated by analysis of a reference material (BCR CRM 723) and applied to the analysis of road dust samples collected in downtown Vienna. Pt and Pd concentrations in samples collected in summer and in winter were compared, with concentrations ranging from 205 to 1445 ng g−1 for Pt and from 201 to 1230 ng g−1 for Pd.Graphical AbstractMesoporous silica microparticles (μPs) functionalized with quarternary amino groups were used for isolating platinum and palladium from aqueous road dust digests. The μPs were suspended directly in the aqueous digests, and the analyte-loaded μPs were analyzed using “dispersed particle extraction”.

Levels of Trace Elements in the Aqueous Humor of Cataract Patients Measured by the Inductively Coupled Plasma Optical Emission Spectrometry

“…The elimination of artifacts is possible due to the species-specific isotope dilution method. To eliminate non-spectral as well as spectral interferences caused by the presence of organic compounds or salts as components of solvents, used for elution, the concept of dispersed particle extraction (DPE) was introduced [32,33,34,35]. In this case, the analyte-containing sorbent is introduced as a specific element into an inductively coupled plasma optical emission spectrometry (ICP-OES) detection device.…”

Combining Dispersed Particle Extraction with Dried-Droplet Laser Ablation ICP-MS for Determining Platinum in Airborne Particulate Matter

“…A detailed description of the method development and the optimum conditions for pre-concentrating Pt and Pd via DPE were reported previously. 16 To perform DPE, 40 µL of a 1 g L –1 suspension of mesoporous sorbent particles were added to the sample digests. The solution was thoroughly mixed (30 s Vortex and 2 min ultrasonication).…”

“…This was repeated one more time for efficient matrix removal. 16 Finally, the particles were re-suspended in 150 µL of a solution containing 2 mol L −1 HF and 1.2 mol L −1 HCl. This last step resulted in the swift disintegration of the sorbent particles.…”

“…The quantification of rhodium was not attempted, since this element is present only at very low concentrations in APM, and since its pre-concentration via dispersed particle extraction is not straightforward. 16…”

“…Many methods are suitable for such a chemical sample clean-up prior to PGE determination in combination with ICP-MS (e.g., tellurium co-precipitation, nickel or lead fireassays), but solid-phase extraction is a widely accepted and practical method (e.g., in the literature 6,[13][14][15] ). Recently, we have presented ''dispersed particle extraction'' (DPE) as an advanced method, which is based on solid-phase extraction, but circumvents some of the latter method's shortcomings (i.e., no ageing of sorbent material, no carry-over, no analyte elution required 16 ). Dispersed particle extraction proved to be a suitable method for quantifying the two most abundant traffic-related PGEs (Pt and Pd) in digested urban road dust, a sample available in large quantities.…”