Determination of Kynurenine Enantiomers by Alpha-Cyclodextrin, Cationic-βeta-Cyclodextrin and Their Synergy Complemented with Stacking Enrichment in Capillary Electrophoresis

Sensitivity enhancement in capillary electrophoresis and their applications for analyses of pharmaceutical and related biochemical substances

“…LODs were 0.12 and 0.06 μmol/L for reduced and oxidized glutathione, respectively [105]. Additionally, acid‐mediated stacking has been employed for the analysis of d , l ‐kynurenine, in human serum and urine samples by cationic‐β‐CD and its synergistic dual chiral selector system with α‐CD in 50 mM borax borate buffer (pH 9.0) [106]. Acid‐mediated stacking enrichment by hydrochloric acid offered the LOD and LOQ of 15 and 50 nM, respectively with good linearity in the range of 50 to 1000 nM and reproducibility (%RSD ≤ 3.35).…”

Chiral Separations by Capillary Electrophoresis and related Techniques with Different Chiral Selectors: A Review

“…The use of different substituents alters the enantioselectivity of the modified β-CDs. Modified β-CDs can be created in neutral [141,143], cationic [144][145][146] and anionic forms [147,148]. Cyclodextrin (CD) and its derivatives are among the most preferred chiral selectors in CE due to their chemical resistance, conveniences related to their structural properties and low UV absorptions [149][150][151].…”

Affinity Capillary Electrophoresis: A Critical Review of the Literature from 2018 to 2020

“…In addition to these common CD, they can also be derivatized to impact unique selectivity. Examples include cationic , and anionic , derivatives, CD–metal complexes, ,, and CD–nanocomposites . Analytes can interact with these by forming an inclusion complex with the cavity or interact via a combination of different molecular interactions, such as hydrogen bonding, polar, and steric interactions .…”

“…While the majority of chiral ACE use a single chiral selector, other reports have shown that a mixture of chiral selectors can achieve better separation. , In 2020, a paper was published using a mixture of cationic β-CD (mono-6 A -deoxy-6-(1-allylimidazolium)-β-CD) and α-CD for the separation of enantiomers of Kynurenine (Kyn), a metabolite of the essential amino acid, Trp . After optimization of the concentrations of α-CD and cationic β-CD, a high resolution ( R s = 11.43) was observed using a 1:1 molar ratio (50 mM/50 mM) with K b values of 6.0 × 10 –5 M –1 and 8.0 × 10 –5 M –1 for D- and L-Kyn, respectively.…”