Hydrophilic interaction liquid chromatography (HILIC)—a powerful separation technique

Hydrophilic interaction liquid chromatography (HILIC) provides an alternative approach to effectively separate small polar compounds on polar stationary phases. The purpose of this work was to review the options for the characterization of HILIC stationary phases and their applications for separations of polar compounds in complex matrices. The characteristics of the hydrophilic stationary phase may affect and in some cases limit the choices of mobile phase composition, ion strength or buffer pH value available, since mechanisms other than hydrophilic partitioning could potentially occur. Enhancing our understanding of retention behavior in HILIC increases the scope of possible applications of liquid chromatography. One interesting option may also be to use HILIC in orthogonal and/or two-dimensional separations. Bioapplications of HILIC systems are also presented

Effects of substituted cyclodextrins on the separation of aromatic sulphonic acids by capillary zone electrophoresis

Effects of the addn. of various additives in the working electrolyte on the selectivity of capillary electrophoretic sepn. of naphthalenesulfonic acids used as intermediates in the prodn. of synthetic dyes were studied. Cyclodextrins form inclusion complexes with various compds. and are not only excellent chiral selectors, but were also successfully applied for sepns. of positional isomers. Me-b-cyclodextrin, heptakis(2,6-di-O-methyl)-b-cyclodextrin, heptakis(2,3,6-tri-O-methyl)-b-cyclodextrin, (2-hydroxypropyl)-b-cyclodextrin and (2-hydroxypropyl)-g-cyclodextrin were studied as isomeric selector additives and compared with unsubstituted b-cyclodextrin. In addn. to the size of the cyclodextrin cavity, the no. and type of the substituents in the cyclodextrin mols. strongly affect the sepn. of isomeric naphthalenesulfonic acids, but the effect of the substituted cyclodextrins on the sepn. selectivity is different for various types of sulfonic acids. Best sepns. of nonsubstituted naphthalenesulfonic acids were achieved in a borate buffer with Me-b-cyclodextrin, whereas the running buffer with nonsubstituted b-cyclodextrin provides superior sepn. of amino and hydroxynaphthalenesulfonic acids. [on SciFinder (R)

Comprehensive profiling of APTS-Labeled N-Glycans using capillary zone electrophoresis/laser induced fluorescence

In this article, a method for the analysis of N-linked glycans derived from glycoproteins is described. Complex mixtures of APTS-labeled neutral and acidic N-glycans were resolved using capillary zone electrophoresis coupled with laser-induced fluorescence detector. All separations were carried out on a polyacrylamide coated capillary with reduced electroosmotic flow. N-glycan pools released from several standard glycoproteins were analyzed in order to generate a migration time database used for the identification of N-glycans released from more complicated samples. In addition, enzymatic digestions using specific and non-specific exoglycosidases were used to positively identify glycan isomeric structures

Comparing SMB Chromatography with Low Capacity/High Selectivity and High Capacity/Low Selectivity Chiral Stationary Phases

Simulated moving bed (SMB) chromatography is increasingly applied in the pharmaceutical industry. Numerous chiral stationary phases (CSPs) exist for enantioseparations. The adsorption behavior of the enantiomers can differ significantly on these CSPs (depending on system, mobile phase composition, adsorption mechanisms, ...). Frequently several CSPs are available to perform the same separation. Objective of this work is to examine the impact of the adsorption equilibrium functions on the productivity in enantioseparations by SMB chromatography for different combinations of CSP/mobile phase