Those bubbles are mostly air - expelled out of the water by heat of mixing (simple alcohols and water generate fairly huge heat upon mixing). Crystalline sugars heat of mixing/dissolution is negative (which is why tea gets cooler when you add sugar to it). Not sure what glycerol+water mixtures do in these terms...
Artem "Nothing is built on stone; all is built on sand, but we must build as if the sand were stone" Jorge Luis Borges -----Original Message----- From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of Jacob Keller Sent: Monday, July 06, 2009 6:40 PM To: [email protected] Subject: Re: [ccp4bb] Bubbles on crystals Perhaps the bubbles are related to the bubbles which form when mixing alcohols with water, e.g., when making coomassie destain? And what are those bubbles, by the way? Jacob ******************************************* Jacob Pearson Keller Northwestern University Medical Scientist Training Program Dallos Laboratory F. Searle 1-240 2240 Campus Drive Evanston IL 60208 lab: 847.491.2438 cel: 773.608.9185 email: [email protected] ******************************************* ----- Original Message ----- From: <[email protected]> To: <[email protected]> Sent: Monday, July 06, 2009 5:56 PM Subject: Re: [ccp4bb] Bubbles on crystals > Hi, > > If you're worried - instead of transfering the crystal, just flood the > entire drop with excess of your cryo buffer. No exposure to air this way. > I bet that the bubbles won't go away though :) > > Artem > >> Dear members, >> I have protein crystals grown in a condition with Isopropanol (13%) and >> citric acid (0.2 M). When I transfer the crystals to cryo-buffer (30% >> glycerol or 25% ethyleneglycol with 0.25 M citric acid and 13%-15% >> Isopropanol), small bubbles appear on the surface of the crystals. These >> tiny bubbles sometimes disappear in few seconds and sometimes not. >> Crystals >> are exposed to air only for 2-3 seconds in the process of transfer. I am >> worried if the formation of these bubbles is due to evaporation of >> isopropanol form the crystal and if it affects the crystal lattice. These >> crystals diffract X-rays upto 4 angstroms. Any ideas how to avoid this >> problem? >> Thank you >> Kumar >> >
