I also used to store my PEG solutions in light, and my stocks do sit out on the bench. I can't say for sure whether light or temperature make a difference, but I like to heed what seem like superstitions in crystallography to eliminate variables. We purchase our screens from Qiagen, who suggests that blocks be stored in the fridge and warmed to RT before use.
Best, Chris On 7/14/14, Nicholas Larsen <nicholas_lar...@h3biomedicine.com> wrote: > I don't think storage matters. I doubt Hampton stores their PEG stock > solutions at -80 before they ship out to customers. > I've solved tons of structures leaving my PEGS and PEG screens at RT in the > light. > > Nick > > > On Mon, Jul 14, 2014 at 12:32 PM, Chris Fage <cdf...@gmail.com> wrote: > >> Hi Jerome, >> >> -I have heard that PEG solutions can become unstable in light. We usually >> store our block in the fridge, where photons are scant anyway. For any >> stocks that I prepare, I wrap the tube/bottle in aluminum foil. I'm not >> sure about freezing them. >> -Some labs (not ours) evidently prepare buffered stocks of PEG solutions, >> as their pHs tend to shift with time. This is something I've been meaning >> to try. Of course, you may need to worry about buffer components that are >> incompatible with crystal hits. >> >> Hope this helps, >> Chris >> >> >> On Mon, Jul 14, 2014 at 9:33 AM, Jerome Nwachukwu <jnwac...@scripps.edu> >> wrote: >> >>> Dear all, >>> I have 3 short questions about PEG solutions: >>> Does anyone know the best way to store crystallization screening blocks >>> that contain PEG 3350? >>> Is it a good idea to freeze the PEG solutions at -80°C and thaw them >>> before use? >>> Would the freeze-thaw process considerably alter the PEG chain lengths? >>> >>> Thank you, >>> -Jerome >>> >>> Jerome Nwachukwu >>> >> >> > > -- > [This e-mail message may contain privileged, confidential and/or > proprietary information of H3 Biomedicine. If you believe that it has been > sent to you in error, please contact the sender immediately and delete the > message including any attachments, without copying, using, or distributing > any of the information contained therein. This e-mail message should not be > > interpreted to include a digital or electronic signature that can be used > to authenticate an agreement, contract or other legal document, nor to > reflect an intention to be bound to any legally-binding agreement or > contract.] >
