Also, cacodylate contains arsenic which is heavy, and thus has a much larger X-ray absorption cross section than do buffers constituted of lighter atoms. There is therefore a bigger dose (Joules/kg of crystal) absorbed with cacodylate in the buffer than there would be without it (and no extra diffraction strength), so that is another very good reason to avoid it, or to buffer exchange it out before the diffraction experiment.
Elspeth -----Original Message----- From: CCP4 bulletin board [mailto:[email protected]] On Behalf Of Jim Pflugrath Sent: 23 November 2011 18:11 To: [email protected] Subject: Re: [ccp4bb] dark progression of radiation damage Any cacodylate buffer will cause gas to be produced. One only needs a minute exposure on a modern home lab source to see this happening. I suggest that everyone avoid cacodylate in their crystallization drops that end up being exposed to X-rays. Jim ________________________________________ From: CCP4 bulletin board [[email protected]] on behalf of Sanishvili, Ruslan [[email protected]] Sent: Wednesday, November 23, 2011 11:49 AM To: [email protected] Subject: Re: [ccp4bb] dark progression of radiation damage I think I need to clarify couple of things in my recent post about "exploding" crystals during re-mounting by a robot. First, it was a bit ....
