Univerzita Pardubice Fakulta chemicko- technologická

Univerzita Pardubice

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Publikace detail

HILIC-RP Dual Retention Mechanism on Polar Embeded Silica Stationary Phases

Autoři: Janás Petr | Jandera Pavel

Rok: 2016

Druh publikace: ostatní - přednáška nebo poster

Strana od-do: nestránkováno

Tituly:

Jazyk	Název	Abstrakt	Klíčová slova
eng	HILIC-RP Dual Retention Mechanism on Polar Embeded Silica Stationary Phases	The selectivity of the chromatographic system can be adjusted not just by the change of the stationary or mobile phase. If water-organic mobile phase is employed on moderately polar stationary phases, two kinds of retention mechanisms usually appear according to the concentration of water in mobile phase. If there is a low content of water in mobile phase (2-40%), water tends to being adsorbed onto the surface of polar stationary phase, what leads to the formation of a diffuse layer. Under these conditions, partition to the water layer predominates and the method is called hydrophilic interaction liquid chromatography (HILIC). With the increasing concentration of water, the diffuse layer is supressed, thus the changes in the retention mechanism emerge; dispersive interactions are the driving force of the retention and an organic modifier becomes stronger elution agent. This signifies RP system begins to predominate. Dual retention mechanism was confirmed on three diol and one amide bonded columns. The retention of some phenolic compounds was measured over broader range of content of water in mobile phase and the plots of retention factors on the volume fraction of water in mobile phase evinced characteristic shape of U-curve [1] with minimum marking the transition between both mechanisms. To ascertain the broadest operability in the HILIC mode, volume fractions of water in mobile phase corresponding to the minimum of U-plots were compared between individual columns. From this point of view, TSKgel amide 80 with bonded carbamoyl groups provided the most favourable results. Since around the minimum the retention is too low and successful separations can be accomplished maximally to the φH2O=0,25, better indicator is the volume fraction of water in mobile phase corresponding to k=0,5 (log k=-0,3), which is on average the highest on the TSKgel amide 80 column, too.	HILIC; RP; dual retention mechanism; chromatography column