DCM safety

[pgiorgos]

Hello again guys

Guess what am i going to talk about. safety in the lab  :p. My question is about dicloromethane this time. I have a very specific question about this stuff. I was performing an experiment in the hood and i wanted to do  TLC with dichroromethane and methanol (98/2 % ) I used 49ml of DCM and 1 ml of Meoh and i put my tlc plate inside the chamber for TLC. The absorber was at high level inside the hood but the glass of the hood was not closed all the way down cause i could not work. My head of course was outside. I had an acidic odor for a long (like an acidic sensation on my nostrils) and a bit cough when i came back home. Is DCM so hazardous in such amount (i used 98 ml in total cause i performed 2 TLC) inside a hood to cause problems? i was thinking maybe it was from the TLC plate (silica) but i know that DCM is not so safe. I have seen people perform TLC with DCM out of the hood and handle it (transfer liquids) out of the hood and sometimes poor it on the bench. Sorry if I ask safety issues but as i have said i want to handle everything in a right way. My supervisor just told me to do it in the hood and he didnt say that i do something wrong. If it was not DCM do you thing that silica plates is very dangerous (i cut it right but sometimes maybe it has some dust from the cut)

[hypervalent_iodine]

It has a very distinctive smell, but I wouldn’t call it acidic. I have inhaled DCM before and from memory it can sting a bit, but it isn’t lingering. I believe the main problem with it is more the long term effects from constant exposure, anyway (as well as environmental concerns). Was / is your hood working - i.e was it sucking in air? You can check by getting a bit of paper towel and seeing if it is pulled into the hood when held just under the sash. If it is, and if everything was fully contained to the hood, you shouldn’t have inhaled much or any. The culprit may be something else in the lab. Did you let the plate dry fully before developing it?

 

Side question, 50 mL for a single TLC?! Are you doing prep TLC with huge plates or something?

[pgiorgos]

9 hours ago, hypervalent_iodine said:

It has a very distinctive smell, but I wouldn’t call it acidic. I have inhaled DCM before and from memory it can sting a bit, but it isn’t lingering. I believe the main problem with it is more the long term effects from constant exposure, anyway (as well as environmental concerns). Was / is your hood working - i.e was it sucking in air? You can check by getting a bit of paper towel and seeing if it is pulled into the hood when held just under the sash. If it is, and if everything was fully contained to the hood, you shouldn’t have inhaled much or any. The culprit may be something else in the lab. Did you let the plate dry fully before developing it?

 

Side question, 50 mL for a single TLC?! Are you doing prep TLC with huge plates or something?

I used such amounts cause i had a lot of samples to spot so i wanted a big chamber. The hood is in a very good situation and it works fine. My problem is that everyone in the lab use DCM out of the hood. They want to run a TLC plate and they dont prepeare the chamber in a hood. They transfer liquids with DCM out of the hood and sometimes they evaporate out of the hood. I m not sure about the smell of DCM but i dont want to learn :P. Maybe i smell it every day but i dont know if its DCM or not. I AM GOINT TO STAY for 8 months in the lab so sometimes i think that its not a long period to get a serious damage but i am not sure. I think its not good for the others too. I really dont know 

[hypervalent_iodine]

DCM is not something I would use outside of a hood unless I was putting it on a rot evap. I think you are probably okay, but if you are uncomfortable with people using it outside of a fume hood, I would speak to someone about it. If you are concerned about symptoms, you should see a doctor. 

Also, regarding your question about the silica plate - it does not give an acidic smell, but I would avoid the dust. Small bits from cutting plates aren't anything to worry about, but larger amounts of free flowing particles (for say, columns) you should be mindful of and only work with inside a hood. 

[pgiorgos]

22 hours ago, hypervalent_iodine said:

DCM is not something I would use outside of a hood unless I was putting it on a rot evap. I think you are probably okay, but if you are uncomfortable with people using it outside of a fume hood, I would speak to someone about it. If you are concerned about symptoms, you should see a doctor. 

Also, regarding your question about the silica plate - it does not give an acidic smell, but I would avoid the dust. Small bits from cutting plates aren't anything to worry about, but larger amounts of free flowing particles (for say, columns) you should be mindful of and only work with inside a hood. 

Thank you for the answer my friend. I cannot understant why some people dont care about safety. Sometimes i want to quit lab cause of the "dont care" of some people. They use substances like this in a way that its not correct and we inhale a lot of things. Sometimes i dont know exactly what they use and accidentally i smell ammonia, dcm, acetic acid sometimes. I hope that i wont have a big problem for the short period i will be there (about 8-9 months). I want to do something else but i love science so i want to stay for these months. I take measures but sometimes i cannot avoid smell small amounts of organic solvents like dcm because someone forget the hood, forget to open windows, forget to inform etc. We live in a hurry and we forget serious things sometimes. So now i think that my cough is due to dcm or i am too anxious and i think such things. I really dont know. Thank you again my friend.