Enteric Coated Vitamin A

[Lana]

I'm having a difficult time in liquid-liquid extraction of vitamin A. My coating is cellulose acetate phthalate and I can't seem to dissolve the coating without affecting the vitamin A (I'm not getting any readings when I analyze it with the fluorometer). I've used the organic solvents, methanol, chloroform, and hexane for analysis, but no results.
Does anyone have any suggestions as to how to prepare my sample to analyze the vitamin A in my coated samples?

[gcguy]

It may sound obvious, but have you tried crushing the sample before extraction? If it is a coating then this should defeat it. If you are cruching the sample then it may not be the coating that is causing problems.

GCguy

[Lana]

My samples are already in powder form, ranging in the size of 5-15 um, so I can't crush the coating. Thanks for the suggestion though!