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Advances in multi-dimensional LC - A combination of on-line and off-line approach using two separation modes on a single column
Autoři: Jandera Pavel | Hájek Tomáš | Staňková Magda
Rok: 2016
Druh publikace: ostatní - přednáška nebo poster
Strana od-do: nestránkováno
Tituly:
Jazyk Název Abstrakt Klíčová slova
eng Advances in multi-dimensional LC - A combination of on-line and off-line approach using two separation modes on a single column Multidimensional LC separations can be performed coupled either on-line or off-line, in time or in spatial domains, and their possible combinations. Using off-line or stop-and-go time-based 2D LC, we could theoretically separate a sample containing even several tens of thousands compounds, at the price of the separation time taking too long a time, even several days and high sample dilution (drop in sensitivity). In practice, the 2D separation in time domain is usually not sufficient for analyzing samples containing more than 100 - 200 relevant compounds using various multi-dimensional setups. As a way to solve this problem, we developed an automated dual LCxLC approach, enabling large essential changes in separation selectivity on a single column by large modulation of retention mechanism adjusting the mobile phase. Some polar columns allow fast transition from HILIC mechanism by adjusting the composition of aqueous-organic mobile phases, from high concentrations (60-95%) of organic solvent (acetonitrile), to reversed-phase mechanism showing completely different selectivity and elution order at less than 40% organic solvent in water, in alternating gradient elution runs during a single experiment on a single column. A monolithic zwitterionic sulfobetaine polymethacrylate micro-column BIGDMA-MEDSA, designed in our laboratory, shows such a dual retention mechanism: HILICIn acetonitrile-rich mobile phase, and RP with major role of hydrophobic interactions in more aqueous mobile phases. The BIGDMA-MEDSA column can be used in the first dimension of two-dimensional reversed-phase (RP) and HILIC modes, coupled with an alkylbonded core-shell or silica-based monolithic column in the second dimension, for alternating HILIC×RP and RP×RP comprehensive two-dimensional separations of a single sample. multi-dimensional liquid chromatography; HILIC; RP; monolithic column; dual retention mechanism