In general I think they should be ok. Some componenents may slowly oxidize or otherwise deteriorate, but as long as there is nothing growing in the solutions, you should be ok. If you experience irreproducibility when you try to follow up on a successful condition, it is good to keep in mind that this might be a reason why (but then so can be a different water source, etc.). You might want to filter the solutions with a 0.2 micron syringe filter (one for each solution).
On Thu, 27 Dec 2007 10:34:31 -0800 Ngo Duc Tri <[EMAIL PROTECTED]> wrote: Dear CCP4 users, I'm sorry for non-ccp4 question. My lab is using protein crystalization screening from Hampton and Emerald. However I noticed the Expires Date was 05/2002. That means we are using the too old chemical. Could I ask your experience about this problem? Should I need to remove these expired screening because we still have many stocks. Thank you for your reply. My best regards, TriNgo PhD Student, Sungkyunkwan University