Wednesday, September 23, 2015

10 ul pipet tips

Small, useful things - links:
  • I thought this The Atlantic Monthly article on firefighters, fire retardants and cancer was interesting, but wasn't very convincing. It's worth reading the comments - believe it or not, there is some level of subject matter expertise. 
    • Isn't the real cancer hazard from house fires polyaromatic hydrocarbons? I am very willing to believe "firefighters have a much higher exposure to carcinogens", but less willing to attribute them to fire retardants combustion products. 
  • Slate has a long article on methylene chloride (fixed!) and people who die from using it while stripping bathtubs. Gotta say, I would definitely want to avoid that. 
    • Bathtubs are 1) large items that'd require a lot of DCM to strip, 2) in a small space that requires lots of ventilation. Isn't that the root of the problem? In that case, perhaps any potential asphyxiant is a bad idea. 
  • Good article by Hepeng Jia of Chemistry World on the Tianjin incident. Ammonium nitrate seems to me to be the "horses-not-zebras" answer here. 
  • I liked this Carmen Drahl piece on new findings on the Nazi nuclear reactor. 
  • Interesting piece by Mark Lorch on the Chinese terracotta army and their chrome-plated swords.
  • I had no idea that Bruker had a blog, but it is gorgeous. Good post on honey.
  • I hope you'll join Jyllian Kemsley and Mary Beth Mulcahy at this ACS webinar on the Sangji case.
  • Prof. Shawn Burdette has some questions for you, regarding what he believes to be some erroneous papers. 
Readers, anything that I missed? 


  1. PBDEs ain't exactly good for you before they burn, either.

    1. That's fair, but what's the exposure level for them?

  2. Regarding Shawn Burdette's objections: I never did understand how Fe(III) was supposed to enhance an organic molecule's fluorescence when all of the (non-fluorimetric Fe(III) sensor) reports that I've seen amply show that paramagnetic metal ions quench fluorescence.

  3. 1) If flame retardants actually stop stuff from burning, the firepeople aren't exposed selectively to them. (To their combustion products, yes, but not to them.)
    2) How much flame retardant is in an object? A sofa weighs > 100 lbs - how much of that is flame retardant? How does the amount of halogenated stuff generated in a house fire compare to that of, say, PVC piping?

    I guess I'd be more worried about burning electronics and pipes - metals burn, but don't burn down to better stuff, generally.

  4. CJ, the link about methylene chloride sends me to a 404 page on slate. Is it just me?

  5. This is the correct link:

    A quote from the article says "An open flame, meanwhile, can transform methylene chloride to phosgene. "

    Is it true??

    1. I am sure there are cases where you can oxidize DCM to phosgene, but I don't think an open flame is one of them?

    2. Yes, an open flame will produce phosgene from DCM although the amount can really vary. It's one of the reasons not use DCM paint strippers in an area heated by a device with an open flame or in an area where there are things like furnaces or hot water heaters. It amazes me that anyone would essentially ignore the safety warnings and fill an open bathtub with DCM in an enclosed bathroom and not expect to have real problems. I've been taught that DCM quickly overwhelms standard respirator cartridges so that containment of the vapors using engineering controls along with supplied air through helmets or the equivalent is the only way to go. Of course, if you are using relatively small amounts of DCM strippers in a WELL VENTILATED area like outside or in a garage with a fan, you should be alright.

    3. Got a literature cite for "an open flame will produce phosgene from DCM although the amount can really vary"?

    4. This might be useful:


looks like Blogger doesn't work with anonymous comments from Chrome browsers at the moment - works in Microsoft Edge, or from Chrome with a Blogger account - sorry! CJ 3/21/20