HPLC Resolution of Hydroxyl Carboxylic Acid Enantiomers Using 2-Quinoxaloyl Chloride as a New Precolumn Derivatizing Agent

Chiral α-hydroxy carboxylic acids were reacted using 2-quinoxaloyl chloride to form UV and fluorescent derivatives. Under mild conditions either in aqueous or non-aqueous conditions reaction proceeds quickly and without racemisation. The labelled compounds have been resolved into enantiomers on β-cyclodextrin bonded stationary phase operated with polar organic eluents. The high sensitivity and selectivity of the method has been used for the determination of low levels of enantiomeric impurities in commercial "pure" samples.