Ion-pair high-performance liquid chromatography of diaminopimelic acid in hydrolysates of physiological samples.

A method is reported for the determination of diaminopimelic acid (DAPA) in physiological samples. DAPA is derivatized with an o-phthaldialdehyde reagent solution, subjected to reversed-phase high-performance liquid chromatography and detected spectrofluorometrically. The method is a significant advance over previous methods because it uses the ion-pairing agent hexadecyltrimethylammonium bromide (HTMA) to facilitate DAPA measurement. Ion-pairing with HTMA avoids interference with co-eluting derivatives to provide simultaneous, sensitive, reproducible measurement of both DAPA peaks (DD,LL-DAPA and DL-DAPA).