HPLC Method for Separation of a Mixture of Tryptophan and its Catabolites on Zodiac HST OG Column

Tryptophan is an essential amino acid involved in protein synthesis and serves as a precursor to several bioactive molecules including serotonin and melatonin. Its catabolites, formed primarily through the kynurenine and IDO pathways, include neuroactive and immunomodulatory compounds such as kynurenine, kynurenic acid, xanthurenic acid, 3-hydroxykynurenine, and quinolinic acid.

These compounds can be effectively retained, separated, and analyzed using the Zodiac HST OG mixed-mode column. A gradient mobile phase comprising water, acetonitrile (MeCN), and sulfuric acid as buffer enables robust separation. Detection is performed at 220 nm (UV) with good resolution and peak shape.