Combination of Medium- and High-Pressure Liquid Chromatography for Isolation of L-tryptophan (Q-marker) from Medicago sativa Extract

Medicago sativa (alfalfa) is a widely used animal feed. However, its quality has been difficult to control due the lack of appropriate marker compounds. Therefore, it very necessary select an (Q-marker) quality. In this study, medium-pressure liquid chromatography and high-pressure were employed effectively prepare separation Q-marker (L-tryptophan) from sativa. Firstly, using MCI GEL® CHP20P as stationary phase, 2.5 g target fraction Fr3 was enriched crude extract (2.9 kg) by chromatography. Secondly, Sephadex LH-20 further separate fractions, Fr34 (358.3 mg) after 14 repetitions. Lastly, ReproSil-Pur C18 AQ preparative column, 63.4 mg L-tryptophan obtained chromatography, purity above 95%. The results showed that (MCI LH-20) combined with (ReproSil-Pur AQ) could be natural products satisfactory purity.