[topenator]

I am required to make my organic sample a picrate by using saturated picric acid in water. What other chemicals can I use to make my sample a crystal/salt?

[rolnor]

Oxalic acid is good for amines sometimes. It can be used as solution in ether.

[hollytara]

Picric acid is a problem. 

Can you give us other information - what is the type and purpose of the sample?  What is it that is "requiring" you to make the picrate?

[topenator]

I have a yam tuber sample which I freeze-dried and macerated with 95% ethanol, then I concentrated it using a rotary evaporator and dissolving in 5% acetic acid. Then, I got an acid supernatant which I filtered and made alkaline by using ammonium hydroxide then extracting it with DCM using a separatory funnel. I used the rotary evaporator again by using the combined DCM extract and used a small amount of absolute ethanol. Then I was supposed to use a saturated picric acid in water to form a picrate but for reasons (explosive, I am an undergrad. student) it is not available. I am trying to purify my sample (which is an alkaloid) which is why I'm trying to find alternative chemicals to form a salt/crystal just like what a picric acid can do which will not affect my sample as i imagine.