A simplified HPLC method for determination of tryptophan in some cereals and legumes

Abstract In the present study, a simple analytical method is proposed for determining tryptophan, and method is validated on some cereal and legume samples. In the method alkaline hydrolysis of proteins was used due to the destruction of tryptophan structure during acid hydrolysis. Following alkaline hydrolysis (120 °C for 12 h), hydrolysates are filtered through ashless filter paper and pH values are adjusted with hydrochloric acid solution. Separation and detection of tryptophan are performed on a reversed-phase column with fluorescence detection within 10 min by using a mobile phase of acetonitrile and acetate buffer of pH 6.3 (1:9, v/v). For determination of tryptophan content, the procedure described in the study offers an alternative analysis method by enabling high speed analysis and the use of simple extraction process to the other available methods.