When using spin concentrators, always remember to not spin more than 4-6min before remixing the content of the concentrator by pippetting, to prevent concentration gradient and subsequent precipitation at the bottom. Jan
Jan K Jensen, Pl-R, Ph.D. Post doctoral fellow at University of Illinois at Chicago (UIC) Laboratory of Peter GW Gettins Department of Biochemistry and Molecular Genetics MBRB Room 1260 900 S Ashland Chicago Il, 60607 -----Original Message----- From: CCP4 bulletin board [mailto:ccp...@jiscmail.ac.uk] On Behalf Of Matthew Alan Bratkowski Sent: Tuesday, May 05, 2009 2:45 PM To: CCP4BB@JISCMAIL.AC.UK Subject: Re: [ccp4bb] Lost my protein Hi. I have experienced similar problems with the Amicon filters previously. I found that using a swing bucket rather than a fixed angle centrifuge and keeping the speed at 4000 g, the recommended speed, resulted in better yields. If you have a large volume to concentrate (>12 mL), using an Amicon stirred pressure cell first may work better. This prevents repeated spinning of the filter, which is not recommended by the company. In my experience, using the same filter a few times is ok, but I guess that repeated centrifugation could eventually crack the filter. Matt
