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Polar columns with dual-mode retention mechanism in comprehensive HILICxRP and RPxRP liquid chromatography. Monolithic HPLC columns in food analysis

Autoři: Jandera Pavel | Hájek Tomáš | Růžičková Marie

Rok: 2018

Druh publikace: ostatní - přednáška nebo poster

Strana od-do: nestránkováno

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
eng	Polar columns with dual-mode retention mechanism in comprehensive HILICxRP and RPxRP liquid chromatography. Monolithic HPLC columns in food analysis	In comprehensive two-dimensional liquid chromatography, rational combination of separation systems with complementary selectivities in the first and in the second dimension (orthogonal systems) provides large two-dimensional peak capacity for moderately polar analytes. Comprehensive RPxHILIC systems combining reversed-phase chromatography (RP) on a bonded C18 column with aqueous normal phase (HILIC) chromatography on a polar column are highly orthogonal, but mobile phase compatibility in the two systems presents a challenging problem. Small volume sample volume injection may provide a solution. We developed new polar monolithic zwitterionic polymethacrylate micro-columns showing dual retention mechanism: In acetonitrile-rich mobile phase, hydrophilic interactions control the retention (HILIC system), whereas in more aqueous mobile phases the columns show predominantly hydrophobic properties (RP system). Coupled to a short alkyl-bonded core-shell or silica-based monolithic column in the second dimension, a zwitterionic micro-column can be used in the first dimension of a comprehensive two-dimensional LC system, either in the reversed-phase mode (RPxRP), or in the aqueous normal-phase mode (HILICxRP). The first dimension conditions control mainly the retention range of separated sample compounds, both in the RP and in the HILIC mode. The quality of 2D separation, which can be measured by orthogonality, theoretical and practical two-dimensional peak capacity, and peak production rate per separation time, depends primarily on the repeating reversed-phase gradients in the second dimension, which must be very fast (1 minute or even less). We investigated the effects of the second-dimension column (type - core shell versus monolithic -, length, diameter, stationary phase chemistry, particle size), mobile phase flow-rate and gradient type (full-in-fraction, segment in fraction, continuously shifting), range and time, on comprehensive HILICxRP and RPxRP 2D. A comprehensive L	two dimensional liquid chromatography; monolithic column; zwitterionic column; dual retention mechanism; hydrophilic interaction liquid chromatography

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