I extracted the NAMI tubers with 95% ethanol by cold maceration. The extract was concentrated under reduced pressure until dryness then I dissolved it in 5% acetic acid. The acid supernatant was filtered and made to alkaline by ammonia water then extracted with dichloromethane until the base was exhausted. The combined dichloromethane extract was evaporated under reduced pressure to give a syrupy mass which then was dissolved in a small amount of absolute ethanol. Saturated picric acid in water was added to form yellow Dioscorine picrate.

What other alternative acids/chemicals should I use aside from using picric acid (which is explosive)? I'm an undergraduate student.