Sciencemadness Discussion Board

Sodium metabisulfite - this stuff is nasty!

Upsilon - 21-9-2015 at 15:47

My order of sodium metabisulfite arrived today. Opening the bag was enough to stir up the slightest amount of powder, which quickly dissipated after exiting the bag. Even then, this stuff is just as bad as chlorine gas. My nose felt like I was inhaling acid. Soon after I had some minor coughing. Needless to say I quickly closed the bag and got away.

Sodium metabisulfite is supposed to release sulfur dioxide on contact with moisture. I was surprised that the few particles that actually made it to my nose were able to combine with the moisture in it to generate enough sulfur dioxide to warrant such an extreme reaction. If anyone else is going to use this stuff, make sure you do so in a well ventilated area.

DraconicAcid - 21-9-2015 at 16:54

I've been making wine for years, so you don't have to tell me twice.

byko3y - 21-9-2015 at 16:56

Have never had such problems. Try to work with potassium cyanide. You will either learn, or...

cyanureeves - 21-9-2015 at 17:20

first time i got mine it irritated my sinuses and caused itchy ear canal. i like to sniff it every time i recover gold.years later i broke out in hives when i was taking Sulfamethoxazole.they took me off it and was told i could never take Sulfonamides.every time i take a whiff of smb i get an allergy tease and i like it.

[Edited on 9-22-2015 by cyanureeves]

woelen - 21-9-2015 at 22:47

If you call Na2S2O5 nasty, then what do you call stuff like 37% HCl, Cl2, Br2? Or even stuff like POCl3, AlCl3?

Many chemicals can be pungent, but they can be handled very well, if treated with care. Na2S2O5 is one of the more benign chemicals. The fact that it is sold to the general public without any questions asked already is a demonstration of that.

phlogiston - 22-9-2015 at 01:29

While Na2S2O5 can certainly be handled safely, it can be a little unexpected for a solid material to be so easily dispersed and inhaled. At least with concentrated acids /volatile liquids/gasses, you anticipate the corrosive and toxic vapour and act accordingly.

I was caught off guard like this the first time I was making a solution of sodium dodecyl sulfate, SDS. As soon as you open the container, no matter how carefully, a fine 'mist' of extremely irritant powder floats and spreads in the air. The only reasonable way to weigh it is with a balance in a fume hood, even though the turbulence messes up the weighing accuracy.

[Edited on 22-9-2015 by phlogiston]

woelen - 22-9-2015 at 01:53

One of my biggest surprises I once had was when I received an order of technical grade AlCl3. I opened the bottle of the material and was greeted with a loud hissing noise and a dense cloud of HCl-fumes as soon as I opened the bottle. The bottle was pressurized like a coca cola bottle, but instead of CO2 a cloud of HCl escaped from the bottle. I felt the heat of the HCl-gas hydrating on my skin and had to step back to avoid inhaling the dense fumes.

Harristotle - 22-9-2015 at 02:58

SO2 forms adducts with proteins, including but not limited to with cysteine residues.

That is not, in itself, exciting, but the immune system can sometimes mount a response against them. So a couple of 10s of nanomoles of SO2 can have the effect of unleashing a storm of H2O2, hypochlorous acid, - all of the good things that the NADPH oxidase system that kills bacteria that get inside your body. In extreme cases, red wine, with its 100ppm SO2 has killed sensitive people.

This is mentioned in the abstract to the review http://www.ncbi.nlm.nih.gov/pubmed/3302664 - I don't have a primary reference to hand. 5% of asthmatics is not insignificant!

ave369 - 22-9-2015 at 08:24

It's just a stinky salt, similar to salt of hartshorn. I've received a shipment of the latter today; the entire parcel reeked of ammonia, despite that the container with the salt of hartshorn was closed tightly. I have yet to open this container; right now it sits in my reagents cabinet and stinks there.

[Edited on 22-9-2015 by ave369]

Upsilon - 22-9-2015 at 08:48

Quote: Originally posted by woelen  
If you call Na2S2O5 nasty, then what do you call stuff like 37% HCl, Cl2, Br2? Or even stuff like POCl3, AlCl3?

Many chemicals can be pungent, but they can be handled very well, if treated with care. Na2S2O5 is one of the more benign chemicals. The fact that it is sold to the general public without any questions asked already is a demonstration of that.


I have dealt with concentrated HCl and chlorine gas before. I definitely had a worse reaction to this than I do with HCl. I have also been in a chlorine gas cloud significant enough to the point where I couldn't breathe and ran away as fast as I could. Maybe it's not as bad as chlorine gas, but I was caught off guard by how hard such a small amount of this stuff hit me.

woelen - 22-9-2015 at 22:37

Especially when you start doing experiments then it is very good practice to do them on a micro scale (e.g. use test tubes instead of beakers or jars for your reactions). Being enveloped in clouds of chlorine gas is very risky. What if you stumbled and fell to the floor and were not capable of running away in time?

Upsilon - 23-9-2015 at 16:21

Quote: Originally posted by woelen  
Especially when you start doing experiments then it is very good practice to do them on a micro scale (e.g. use test tubes instead of beakers or jars for your reactions). Being enveloped in clouds of chlorine gas is very risky. What if you stumbled and fell to the floor and were not capable of running away in time?


Other people were nearby that could have done something. I never do any particularly dangerous experiments when I'm alone.

Deathunter88 - 23-9-2015 at 22:25

Quote: Originally posted by Upsilon  
Quote: Originally posted by woelen  
Especially when you start doing experiments then it is very good practice to do them on a micro scale (e.g. use test tubes instead of beakers or jars for your reactions). Being enveloped in clouds of chlorine gas is very risky. What if you stumbled and fell to the floor and were not capable of running away in time?


Other people were nearby that could have done something. I never do any particularly dangerous experiments when I'm alone.


And possibly put the people next to you in danger? It's better to always pretend that you are on your own and that your life depends on yourself.

crestind - 26-9-2015 at 18:25

If you're doing gold refining I would really stick with ferrous sulfate to precipitate HAuCl4. Ferric chloride will do it to, although at a very slow rate.