Dear Peter, my guess is that isopropanol might have evaporated and, in general, that the concentration of PEG4000 might be higher that in the starting solution because of evaporation. I would try to decrease the isopropanol concentration, or even eliminate it.
As a "cooker test" if you smell the original solutions, do they smell isopropanol? Do you have an idea of the initial volume of your kit solution, is it now lower than expected? This might confirm that you had evaporation, if it is larger then, instead of losing water, you had PEG dilution due to water condensing in your tubes. Good luck, Beatrice -------------------------------------------------- Prof. Beatrice Vallone http://biocryst.bio.uniroma1.it/members_vallone.html Dipartimento di Scienze Biochimiche Università di Roma "La Sapienza" P.le Aldo Moro, 5 00185 - Roma Italy Tel +39 06 06 49690276 Fax +39 06 4440062 eMail beatrice.vall...@uniroma1.it ---------------------------------------------------- On Oct 3, 2012, at 11:37 PM, Peter Hsu wrote: > Hi all, > > I recently got some hits from a Mosquito grown at 18C with PEG4000 and 10% > propanol. I've tried reproducing these hits using the standard 24 well format > with no success, even with playing with PEG and propanol concentrations. The > initial screening solution was from a kit that's been sitting in the cold > room for the better part of 2 years. Does anyone here have any tips or tricks > in reproducing crystals grown from organic solvents? > > Many thanks in advance, > > Peter
