Hi Frank, I think the lethal dose is lower than that.. It has acute toxicity (oral, dermal, inhalation) and is hazardous to the aquatic environment. Used as a buffer such as sodium cacodylate (less than 100-200 mM mostly). I would read the Safety information and stick it on the screen :).. but gloves might be enough for the tiny drops in crystal application. Apart from that I don't know what is your policy about purchasing the powder and storing it.. which might be a problem without even making the screen if you are worried. In one of the optimization screens of a condition with three components (Na Caco is one), I couldn't get any crystals when this buffer was replaced with another buffer (I tried a list of ten for buffer optimization covering each a range of pHs), so yes it is sometimes critical. It causes radiation damage when collecting data (keywords: Arsenic, Arsenate..)... you will maybe need many crystals to collect a full dataset.. for a small crystal you might not see the peak of Selenium in a scan (covered because of the caco. use). Regards
toufic el arnaout On Fri, Nov 9, 2012 at 12:26 PM, Frank von Delft < [email protected]> wrote: > Hi all - > > Anybody know > a) how hazardous is cacodylate? > b) does it really matter for crystallization screens? > > It seems by far the most hazardous component of the standard screens; > this 2011 paper seems to think so (bizarrely, I can't access it from > Oxford): > http://onlinelibrary.wiley.**com/doi/10.1111/j.1365-2818.** > 1977.tb01136.x/abstract<http://onlinelibrary.wiley.com/doi/10.1111/j.1365-2818.1977.tb01136.x/abstract> > > and this is site says lethal dose is 0.5-5g/kg: > http://cameochemicals.noaa.**gov/chemical/4468<http://cameochemicals.noaa.gov/chemical/4468> > meaning 2ml of a 0.1M solution contains 1/10th lethal dose...? (Someone > should check my maths...) [Coarse screens come mixed 2ml per condition.] > > > Has anybody done careful experiments that showed it really mattered for a > given crystal -- or even an entire screen? > > So I'm inclined to toss it out entirely rather than make crystallization > screening a "hazardous activity". (We're being subjected to a safety > review.) > > > Thoughts welcome. > phx >
