Preparation of Core–Shell Silica Microspheres with Controllable Shell Thickness for Fast High Performance Liquid Chromatography Separation of Alkyl Benzenes and Intact Proteins

As it is difficult to prevent secondary nucleation and agglomeration during the preparation of core–shell silica microspheres, these issues have been successfully resolved in this study using template-dissolution-induced redeposition. The non-porous particles are transformed into core–shell silica microspheres (CSSMs) in the presence of cetyltrimethylammonium bromide and octyltrimethylammonium bromide under basic conditions. The shell thickness and pore sizes of the CSSMs are controlled by adjusting the etching time and molar ratio of the template, respectively. The CSSMs are modified using octadecyltrimethylammonium chloride to separate the mixture of alkyl benzenes, and a high column separation efficiency is achieved within two minutes. The CSSMs are used for the separation and analysis of proteins and the digests of bovine serum albumin. The chromatographic column packed with core–shell particles affords a significantly higher separation efficiency than the commercial column. Therefore, as a chromatographic stationary phase, these core–shell particles can potentially be used for the fast separation of proteins, small solutes, and complex samples.

HPLC-HRMS Global Metabolomics Approach for the Diagnosis of “Olive Quick Decline Syndrome” Markers in Olive Trees Leaves

Olive quick decline syndrome (OQDS) is a multifactorial disease affecting olive plants. The onset of this economically devastating disease has been associated with a Gram-negative plant pathogen called Xylella fastidiosa (Xf). Liquid chromatography separation coupled to high-resolution mass spectrometry detection is one the most widely applied technologies in metabolomics, as it provides a blend of rapid, sensitive, and selective qualitative and quantitative analyses with the ability to identify metabolites. The purpose of this work is the development of a global metabolomics mass spectrometry assay able to identify OQDS molecular markers that could discriminate between healthy (HP) and infected (OP) olive tree leaves. Results obtained via multivariate analysis through an HPLC-ESI HRMS platform (LTQ-Orbitrap from Thermo Scientific) show a clear separation between HP and OP samples. Among the differentially expressed metabolites, 18 different organic compounds highly expressed in the OP group were annotated; results obtained by this metabolomic approach could be used as a fast and reliable method for the biochemical characterization of OQDS and to develop targeted MS approaches for OQDS detection by foliage analysis.