You can increase the formate concentration and it will be a cryoprotectant on its own. Test increasing amounts until you find the concentrationthat freezed clear as glass and the transfer your crystal to this. We did this with sodium formate at 7 M quite easily.
On Tue, Dec 17, 2013 at 2:59 AM, Tim Gruene <t...@shelx.uni-ac.gwdg.de> wrote: > -----BEGIN PGP SIGNED MESSAGE----- > Hash: SHA1 > > Dear Junyu, > > You can test cryo conditions conveniently in the absence of your > crystals if you have access to e.g. an inhouse machine. Prepare your > solutions with the usual suspects (PEG400; PEG400+glycerol; > butanediol; Na Malonate etc. pp.) at various concentrations, pick up a > large as possible drop with a nylon loop and take a shot to see if you > have ice rings. > Try to be on the safe side with respect to the decision about the > minimal concentration because the presence of the crystal might give a > slightly different result. > > Best, > Tim > > On 12/16/2013 10:36 PM, Xiao, Junyu wrote: > > Dear all, sorry if this topic does not interest you. I wonder > > whether anyone has experience with freezing crystals grown in ~0.2 > > M Magnesium Formate. Garman and Mitchell suggested that "A major > > anomaly is solution 44, 0.2 M magnesium formate, which requires 50% > > glycerol for cryoprotection" in their 1996 paper (J Appl. Cryst. > > 29, 584-587). Since 50% glycerol is kind of harsh, I wonder > > whether anyone has tried alternative cryo protectant. Your kind > > help will be highly appreciated. > > > > Best regards, Junyu > > > > ----------------------------------------------------------- Junyu > > Xiao, Ph.D. University of California, San Diego Leichtag Room 283 > > 9500 Gilman Drive, 0721 La Jolla, CA 92093-0721 Lab phone: > > 858-822-0684 > > ------------------------------------------------------------ > > > > > > - -- > - -- > Dr Tim Gruene > Institut fuer anorganische Chemie > Tammannstr. 4 > D-37077 Goettingen > > GPG Key ID = A46BEE1A > > -----BEGIN PGP SIGNATURE----- > Version: GnuPG v1.4.12 (GNU/Linux) > Comment: Using GnuPG with Icedove - http://www.enigmail.net/ > > iD8DBQFSsBJ/UxlJ7aRr7hoRApCiAJ0b3LyawgscAsIzwFUUHNDqRSplPwCeOZPv > pF9iloWrCgMjIwo4hKlAgN8= > =l4tU > -----END PGP SIGNATURE----- >
