Francoise is right and i want to add one more point. We will aliquot them in smaller volumes and freeze multiple vials. So that we just use the vial once and discard them.
Do you have any idea about sigma P8139 (PMA or TPA). I ordered it and it was send to me in a small vial and it is colorless film so my question is how can I prepare it? I mean how can I dissolve it?