Rinse the inner walls of vial with trimethylsilyl chloride and dry it and then use it for crystallization. Crystals do not stick to the walls so that one can easily scoop them out without damaging it.

Good luck

Balakrishna

Professor Balakrishna Maravanji thanks for your reply! TMSCl we basically kill the free O- on the surface of the glass ? But the question of carefully "scooping" the crystals from the bottom of the scintillation vial remains.

crystals can be removed from the surface and suked up with a plastic pipette, than just quickly remove it from mother solution and transfere to the glass under microscope for future selection/preparation.

The best method strongly depends on the thoughness of your crystals and on the crystallization method. If your crystals are stable outside theys mother solution I would eliminate it with a pipette, add an anti-solvent (better if volatile), and use a glass pasteur (as the sharp corners of its mouth, in my experience, are less prone to damage your crystals than a plastic one) to scrape the bottom and the sides of your vial. If the scaping is too rough for your crystals you can use an ultrasonic bath to detach them from the vial, by quickly submerging and retrieving it in cycles of max a couple of seconds (the more delicate your crystals the qicker and fewer the cycles). If your crystals fade outside their mother liquor this method is still viable, the only precaution is to let them settle in the pasteur before you transfer them on the microscope slide, in order to minimize the transfer of mother liquor (one or two drops max), as it will evaporate (how quickly depending on the solvent) and it may cover your crystals with a powder that may be hard to remove and interfere with single crystal analysis even before you are able to partially dry them with a paper towel and cover your crystals with oil. The anti-solvent avoids completely this problem, so I tend to use it preferentially. Of course the solvents you may use strongly depend on the system you are crystallizing. Good luck.

Thanks for your replies Eduard Rusanov and Jacopo Andreo !

Jacopo Andreo Thanks for the anti-solvent suggestion. That never quite occurred to me. The mother liquor is a saline solution, this makes its even more tricky as any drying of mother liquor leads to formation of NaCl crystals in addition to the crystals I desire. Will definitely try the antisolvent method and get back to this thread for further suggestions.

For small crystals, usually needle in shape, I will take a disposable small gauge needle, file the tip of it so it's not as sharp, then use it as a scoop to pick up the needles. This is tedious for large quantities of crystals, but is fairly quick to collect a few crystals.