Comprehensive Two-Dimensional Liquid Chromatography-Mass Spectrometry in Food Analysis

Food analysis is an interdisciplinary field of research with a significant health, societal, and economic impact. Its scope is to provide a characterization of food products in terms of chemical composition, traceability, safety, quality, sensory properties, and nutritional value. Liquid chromatography coupled to mass spectrometry (LC-MS) has been hitherto the most used platform for non-volatile profile of foods and food-related products. However, in many cases, one-dimensional liquid chromatography (1D-LC) is not capable of providing rewarding results. As a consequence, multi-dimensional and in particular “comprehensive” two-dimensional liquid chromatography (LC×LC) techniques involving two different separation modes have been introduced and used in the last three decades for such a scope. This chapter reports an overview of the main separation modes employed so far in LC×LC in the different research fields. Further, common interfaces, e.g., heart-cutting (LC-LC) and LC×LC (with storage loops or trap columns), novel construction modes, e.g., selective LC×LC (sLC×LC) and pulsed-elution LC×LC, and modulation modes, e.g., vacuum evaporation interface and evaporation membrane modulation, have also been reported.