Benefits and Drawbacks of Fully Porous sub-2 µm and Core-Shell Particles. Comparative UHPLC Applications in Food, Environmental, Forensic, Biopharmaceutical and Natural Products Analyses

Background: In everyday practice, it is necessary to carry out the most number of analyses in the shortest possible time. Therefore, chromatographic systems must usually work above the optimum linear velocity, in order to obtain efficient separations and fast analysis. Objective: This review illustrates the main advantages of the new generation of core-shell particles with respect to the modern totally porous sub 2-µm ones. Method: The benefits of core-shell particles can be summarized as follows: i) superior mass transfer kinetics that leads to better kinetic performance at high mobile phase flow-rate; ii) better column packing quality; iii) possibility to use sub 3-µm core-shell packing column to obtain approximately only half the operating backpressure of the sub 2-µm fully porous particles under their own optimal flow rate. Results: Comparisons between core-shell particles and sub 2-µm ones have been highlighted, making comparative examples of applications in different analytical fields, such as pharmaceuticals, food, environment, forensic and natural products. This multiplicity of applications is a demonstration of the wide use of core-shell particles both for the high efficient separation of small molecules and for that of macromolecules. Conclusion: However, porous silica sub 2-µm particles still have a good part of the market, in particular as concerns food and pharmaceutical analysis. In addition, it is not possible to utilize fully the real separation power of these very efficient core-shell columns because of the ineligible extracolumn effects of the commercially available UHPLC instrument