High-Performance Liquid Chromatographic Analysis of Neurotoxin β-N-Oxalyl-α, β-diaminopropionic Acid (β-ODAP), Its Non-neurotoxic Isomer α-ODAP and Other Free Amino Acids in Lathyrus sativus

摘要

A simple method is proposed for the simultaneous analysis of the neurotoxin β-N-oxalyl-α, β-diaminopropionic acid (β-ODAP) and its isomer α-ODAP, as well as other free amino acids, in Lathyrus sativus extract based on reversed-phase (C18 column) high-performance liquid chromatography (HPLC) of their para-nitro-benzyloxycarbonyl chloride (PNZ-Cl) derivatives. Samples were derivatized in 0.5 M NaHCO3 within 2 min at ambient temperature by adding 50 mM PNZ-Cl in acetonitrile. The PNZ-derivatives were quantified by their UV-absorption at 260 nm. Detection limits were approximately 8 ng mL−1 for both α-, β-isomers, 9 ng mL−1 for homoarginine at a signal-to-noise ratio of 3:1. The coefficients of determination were 0.9967–0.9991. The method was validated by the determination of β-, α-ODAP and homoarginine contents in ethanol-water (30:70, v/v) extracts from the seed and foliage of Lathyrus sativus.