LAUSR

ABSTRACT A new hydrophilic interaction liquid chromatography method coupled with diode-array detector was developed for the determination of 17 underivatized amino acids including L-canavanine in bitter vetch [Vicia ervilia (L.) Willd.] seeds. Amino acids were extracted as free as well as total extracts after acid hydrolysis, followed by chromatographic separation on a Zorbax Rx-SIL column with a mobile phase of acetonitrile/potassium phosphate buffer (12.5 mM; pH 3.0) using gradient elution and detection at 190 nm. The method is characterized by a wide linear range (0.01–200 µg/mL, r > 0.9987), sufficient accuracy (relative error 86.3–109.1%), and suitable precision for the results (relative standard deviation <4.9% in the case of intra-day and <9.8% in the case of inter-day precision). The limits of detection and quantification for free amino acids ranged from 0.01 to 0.24 mg/g and 0.03 to 0.72 mg/g, respectively, whereas the total amino acids ranged from 0.02 to 0.47 mg/g and 0.07 to 1.43 mg/g, respectively. The mean recoveries of free and total amino acids in spiked samples exceeded 70.3% for most amino acids. The mean total content of free and total amino acids in bitter vetch seeds was 1.71 and 14.88 g/100 g seed, whereas the corresponding values for canavanine were 0.07 and 0.19 g/100 g seed, respectively.