Determination of the total tryptophan in food by high performance liquid chromatography combined with enzyme hydrolysis

High performance liquid chromatography was applied for the determination of tryptophan in food. The sample was hydrolyzed in a duration from 16 to 24 hour by protease enzyme at 50o C. The extract was separated on the C8 reversed phase column with mobile phase of NaH2PO4 50mM pH 2.3: Methanol (82:18; v/v). The linearity of the method was kept in the range of 0.5 - 50 mg/L. Limit of detection was found to be 4.6 mg/100g.