High-performance liquid chromatographic separation of aromatic carboxylic acids with β-cyclodextrin-bonded stationary phases

Quantification of Intracellular Metabolites in Escherichia coli K12 Using Liquid Chromatographic-Electrospray Ionization Tandem Mass Spectrometric Techniques

“…Additionally size-dependent and enantio-specific inclusion complexes can be formed (22,38,39). Furthermore, an anion-exchange mechanism has been proposed to account for the chromatographic differentiation of negatively charged compounds (35)(36)(37). However, separation of the analytes is only acceptable for the nucleotides, as can be seen in the differences in retention times (see Table 1) and the necessity of using two columns in series.…”

Separation and Retention Behavior of Aromatic Carboxylic Acid Isomers by High‐Performance‐Liquid‐Chromatography Using β‐Cyclodextrin Bonded Phase with Diamine‐s‐Triazine Moiety

“…It should be noted that, using a b-CD bonded phase without an amino group in the spacer arm, the retention factors of some aromatic carboxylic acids decrease contrarily with increasing the pH of the mobile phase. As the inclusion complexes formed between b-CD and the neutral form of the acidic solutes are more stable than those formed with dissociated species 9 and the pKa value of toluic acid isomers fall in the range 3.91-4.36, 7 it is expected that the dissociated species increases with increasing mobile phase pH in the pH range studied. The elution orders of aromatic acid isomers with different substituents significantly, because various interactions may involve to a different extent in the retention of acidic solutes with different substituents.…”

“…It is of interest to note that the elution order of the three isomers of toluic acid on the bonded phase prepared is consistent with that observed on the three b-CD bonded phases with an amine moiety in the spacer arm. 7 The anionexchange sorption mechanism was proposed by Fujimura et al 7 to rationalize the increase in the retention factor with increasing the pH of the mobile phase, because the secondary amino group in the spacer arm of the amine-b-CD bonded phases and unreacted amino groups on the silica surface were thought to act as the anion exchangers. 7 Similar arguments should also be taken into consideration in the retention of aromatic carboxylic acids on the bonded phase prepared.…”

“…7 The anionexchange sorption mechanism was proposed by Fujimura et al 7 to rationalize the increase in the retention factor with increasing the pH of the mobile phase, because the secondary amino group in the spacer arm of the amine-b-CD bonded phases and unreacted amino groups on the silica surface were thought to act as the anion exchangers. 7 Similar arguments should also be taken into consideration in the retention of aromatic carboxylic acids on the bonded phase prepared. It should be noted that, using a b-CD bonded phase without an amino group in the spacer arm, the retention factors of some aromatic carboxylic acids decrease contrarily with increasing the pH of the mobile phase.…”

“…[2][3][4][5][6][7][8][9][10][11][12] Separations of the isomers of aromatic carboxylic acids using b-CD bonded phases by HPLC have previously been reported. [7][8][9][13][14][15][16][17][18] In our previous publication, the isomers of the five aromatic carboxylic acids, including toluic acid, aminobenzoic acid, nitrobenzoic acid, hydroxybenzoic acid, and naphthoic acid, were effectively separated on an amine-s-triazine-b-CD bonded phase. 18 With the continuation of our studies, it is of interest to further examine the retention of these analytes on the diamine-s-triazine-b-CD bonded phases, so that the influence of the functionality of the spacer arm of the bonded phase on the retention of the analytes can be evaluated and the retention mechanisms can be better understood.…”