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CEC enantioseparations of carboxylic acids on silica‐based monoliths modified with ergot alkaloid derivative
Author(s) -
Messina Antonella,
Moroni Sara,
Flieger Miroslav,
Sinibaldi Massimo,
Ursini Ornella
Publication year - 2009
Publication title -
electrophoresis
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.666
H-Index - 158
eISSN - 1522-2683
pISSN - 0173-0835
DOI - 10.1002/elps.200800788
Subject(s) - enantiomer , chemistry , chromatography , resolution (logic) , silica gel , selectivity , high performance liquid chromatography , carboxylic acid , chiral column chromatography , monolithic hplc column , sorbent , derivative (finance) , urea , organic chemistry , adsorption , catalysis , artificial intelligence , computer science , financial economics , economics
The enantioseparation of carboxylic acids, including amino acid dansyl‐derivatives, 2‐arylpropionic acids and 2‐aryloxypropionic acids, was tested by CEC on a porous silica sol‐gel monolithic column that was prepared by polycondensation of tetramethoxysilane in acidic conditions and post‐gelation heat treatment (120°C for 3 h) in the presence of urea, and successively, by anchoring to the silica (+)‐1‐allyl‐(5 R ,8 S ,10 R )‐terguride as the chiral selector. The bimodal structure of the sorbent showed through pores with a median value of 1.39 μm and a mesopore size distribution ranging between 6 and 12 nm (average pore size of 9.9 nm). To attain optimum separation conditions, the influence of the pH and the concentration of the buffer solution in the mobile phase on resolution were investigated. The monolithic column showed: (i) for the compounds studied resolution values two or three times higher in comparison with previously developed separation systems where the same chiral selector was used. For example, on the monolithic column Dns‐serine enantiomers were much better separated (8 min with a selectivity factor of 1.34) than by HPLC (20 min, α=1.17); (ii) high chemical and mechanical stability as demonstrated by the use of such column for hundreds of analysis along about 1 year without significant variations of the resolution and the retention parameters.