Dear Rashmi, The original standard for microbatch crystallisation is paraffin oil (from Sigma or elsewhere). Drops set under paraffin oil lose almost no water, so it works like a well-sealed batch experiment, in other words you need to have your conditions right and you do get crystals. Paraffin oil is the only case where the reported conditions are the true ones.
Al's oil allows slow water evaporation through the oil, so the drops get slowly concentrated, something like a vapour diffusion, except that you don't have a well-defined end-point, i.e. a reservoir solution. Douglas Instruments I think sell some microbatch plates with a channel around them which can be used as a reservoir for such cases. Al's oil may thus give you more hits, since the supersaturation of the drops gets progressively higher. Of course, you don't know what the true crystallisation conditions are. Silicone oil allows a great deal of evaporation through it, so it may actually give you even more hits but you also may end up with drops drying out before having the chance to produce any crystals, unless you use the plates I talked about before, in which case it works a lot like a vapour diffusion experiment. Have a look at Douglas Instruments' web page: there is a lot of relevant info in there. Cheers, Emmanuel Saridakis ----- Original Message ----- From: rashmi panigrahi To: CCP4BB@JISCMAIL.AC.UK Sent: Friday, April 23, 2010 5:35 AM Subject: [ccp4bb] Setting Microbatch trays !! Hi, While setting up microbatch trays (under oil crystallization), 1. Has anybody used mineral oil (sigma M8410) and obtained some crystal hits? 2. Has anybody used anything other than Al's oil from Hampton, as Parafin oil from sigma or silicone oil from sigma and obtained some crystal hits? Thanks -- rashmi
