Simultaneous determination of tryptophan and kynurenine in plasma samples of children patients with Kawasaki disease by high-performance liquid chromatography with programmed wavelength ultraviolet detection

A simple, fast, sensitive and specific high-performance liquid chromatography (HPLC) method is developed for simultaneous determination of kynurenine (Kyn) and tryptophan (Trp) with ultraviolet (UV) detection setting programmed wavelength. The separation was carried out on an Agilent Hypersil ODS column (125 mm × 4.0 mm, 5 μm) in less than 6 min and the eluate was monitored by the programmed wavelength detection setting at 360 nm from 0 min to 4 min for Kyn, and at 278 nm from 4 min to 6 min for Trp in a single run with UV detector. The linearities of the method were from 0.20 μmol/L to 21.2 μmol/L for Kyn and 2.25–678.0 μmol/L for Trp, and the detection limits were 0.028 μmol/L for Kyn and 0.053 μmol/L for Trp, respectively. Satisfactory precisions and recoveries were obtained by this method. The assay was employed to analyze plasma samples of children patients with Kawasaki disease (KD). The result showed great difference between Kawasaki disease and control group.