you can try to rely on the results of a thin layer chromatography. is risky because you will not work with the results of a chromatographic plate with a sample of pure chloroquine.
in this technique you could do several tests with different solvents until you have finished, but obviously it would be very expensive.
for the technique you would need small smooth plates of glass or metal; some grams of Fluorescent Silica; organic solvents / and water; paper; dropper.
the interpretation of the results would be that there were several marks after the elucidations, the sample is severely contaminated; if it has only one mark, it is theoretically pure, but difficultly you will find only
a brand, even because most of the chemicals have 2-3% impurity. technique will not show the numerical amount of purity without the use of some sophisticated apparatus in the laboratory so it is a risk.
I think you will give up establishing purity because it is very difficult to achieve.
if there were a reaction with 100% yield that gave off a gas, it would be much easier to establish the purity up quantitatively if you use a balance.
