Chromatographic profiles of tryptophan and kynurenine enantiomers derivatized with (S)-4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole using LC-MS/MS on a triazole-bonded column.

d- and l-Tryptophan (Trp) and d- and l-kynurenine (KYN) were derivatized with a chiral reagent, (S)-4-(3-isothiocyanatopyrrolidin-1-yl)-7-(N,N-dimethylaminosulfonyl)-2,1,3-benzoxadiazole (DBD-PyNCS), and were separated enantiomerically by high-performance liquid chromatography (HPLC) equipped with a triazole-bonded column (Cosmosil HILIC) using tandem mass spectrometric (MS/MS) detection. Effects of column temperature, salt (HCO NH ) concentration, and pH of the mobile phase in the enantiomeric separation, followed by MS detection of (S)-DBD-PyNCS-d,l-Trp and -d,l-KYN, were investigated. The mobile phase consisting of CH CN/10 mM ammonium formate in H O (pH 5.