A chromia-based sorbent for the enrichment of phosphotyrosine

Developing of new core@shell particles (CSPs) bearing metal oxides on their outer surfaces is of a great interest. Such hybrid systems have many benefits, i.e., low cost, operation simplicity, chemical stability and tunability along with simple recoverability and reusability that make them suitable as dispersive solid phase extraction (DSPE) sorbents for selecting/extracting different types of molecular structures. Accordingly, herein, novel chromia-based CSPs were successfully prepared and utilized as efficient DSPE for selective enrichment toward phosphotyrosine (pTyr). A modified version of Stöber method was used to prepare highly dispersed core particles that were further coated with the chromium oxide. The outer shell surface morphology and thickness of SiO₂@Cr₂O₃-CSP system were characterized by scanning electron microscopy (SEM) and transmission electron microscopy (TEM), whereas the surface functionalities were determined using X-ray photoelectron spectroscopy (XPS), FT-IR spectroscopy and zeta potential. The prepared chromia sorbent showed a significant improvement in extracting a probe-analyte (pTyr) compared to the results obtained by titania-based counterparts. As well to this, a noticeable stability of the SiO₂@Cr₂O₃-CSP sorbent was remarkably achieved which upon simple solvent-wash cycles, the studied sorbent can be regenerated/reused. Noticeably low-levels of LOD and LOQ (3.0 and 15 pg mL^-1) were attained with good linearity (R² of 0.9995), batch-to-batch reproducibility (RSD% ≤ 10) and run-to-run repeatability (RSD% ≤ 5.5).