You might want to consider misusing the Xe-chamber which a couple of labs and synchrotrons bought in the late 90's to derivative crystals with Xenon. Instead of flushing the chamber with Xenon you could flush it with CO2 then plunge freeze your crystals within the chamber.
careful advertisement follows: http://hamptonresearch.com/product_detail.aspx?cid=21&sid=121&pid=346 [/clicking on links provided through emails are at your own risk/] Jürgen On Oct 2, 2011, at 6:36 PM, Edward A. Berry wrote: Jacob Keller wrote: Dear Crystallographers, I would like to soak my crystals in bicarbonate (a possible substrate), but the crystals have grown--and only grow--in pH 5.2-6.0, so the bicarb/CO2 will just keep evolving out of the solution and reliquishing its hydroxyls until the pH is elevated sufficiently out of range. Does anyone have a clever way of getting bicarb into these crystals? Grow them under CO2? Transfer them to higher pH, and hope for the best? Jacob Keller Assuming they grow by vapor diffusion- how about: Replace the reservoir with diet coke (Perrier water if you want to be high class) with pH adjusted to the range you want and sufficient PEG or glycerol to give the same osmolarity? CO2 diffusing in will lower the pH but not much below that of the reservoir. When you open the well to mount, especially with hanging drops, the CO2 will leave and pH will rise, but not above the starting point. ...................... Jürgen Bosch Johns Hopkins University Bloomberg School of Public Health Department of Biochemistry & Molecular Biology Johns Hopkins Malaria Research Institute 615 North Wolfe Street, W8708 Baltimore, MD 21205 Office: +1-410-614-4742 Lab: +1-410-614-4894 Fax: +1-410-955-2926 http://web.mac.com/bosch_lab/
