Sciencemadness Discussion Board

Chemicals in things used for food.

golfpro - 3-6-2013 at 19:25

Hi, I want to do some things like purify AN by boiling solution on a frying pan, and then leaving this to dry in an oven, but we use these things for food. Are these OK to use after washing them thoroughly? Another example, ethanol for recrystalization in a glass kitchen measuring beaker and that sort of thing

[Edited on 4-6-2013 by golfpro]

adamsium - 3-6-2013 at 20:18

The standard answer is, of course, that you should never, ever mix or dual-purpose labware and kitchenware.

The reality, however, is more like 'it depends'. It depends on what you're placing in the vessels, how well you are able to clean them and how confident you are that they are indeed clean, as well as what risk you're willing to take. In theory, a properly cleaned vessel will likely be cleaner than what you'd ordinarily use in the kitchen. Personally, though, I just think it's a bad idea. Even if you really know what you're doing (and, - if you have to ask questions like this - you don't), there's always the risk of a 'mistake'... not cleaning something properly, things getting mixed up, etc. If you want to do chemistry, you really need gear for doing chemistry, not borrowed kitchenware.

Variscite - 3-6-2013 at 21:55

I agree, never cross-contaminate your lab with your house. Much safer to just use the proper equipment designed for these purposes (heating/drying/chemical attack). Buy yourself some dedicated beakers and a cheap alcohol burner ;).

Magpie - 4-6-2013 at 07:32

Many of my wife's kitchen items have been put to a higher use in my lab. But it's like "roach motel," they check in but don't check out. My wife then gets new bowls, spoons, plates, etc. Where possible I label the requisitioned items "for lab use only!"

Intergalactic_Captain - 5-6-2013 at 06:27

The only thing I've ever felt comfortable with using in this manner is Pyrex (or any off-brand borosilicate) cookware... As long as it isn't scratched/fogged/flawed, and nothing of any signifigant known toxicity is being used, I feel safe with proper cleaning - For example, I used to make quite a bit of black powder via a blender method that I perfected - Would never use that particular blender carafe for food, as it was impossible to clean out every nook and cranny, and for the same reason had another one dedicated solely to aluminum powder... However, I used a standard 9x13 pyrex baking pan for drying, and considering neither KNO3, sulfur, charcoal, dextrin pose any particular health risk, I felt perfectly safe using it for both cooking and chemistry, so long as it was undamaged and properly cleaned between uses...


On the same note, I was thinking on a different line when I saw the title here... Where I work now we have a relatively sane procedure for cleaning of processing equipment on production changeovers - rinse/foam/rinse/sanitize/rinse - The foam step is a high-strength bleach, the sanitizer is bleach and quat-amines... Then we RINSE the sanitizer off - This is an important step that I feel most "cover your ass" type procedural planners don't consider... In a lot of industries (anywhere that uses J&J products, IE every convenience store and fast food place in the US), the "final step" is the "sanitizer" - n-alkyl quat-amines...

...Here's the problem with that - If you don't rinse it off, all that wonderful germ-killing goodness is still there... And then it gets rinsed INTO the product that you're trying to keep clean and safe... Ever wonder why gas-station coffee tastes like crap first-thing in the morning? Someone followed the "proper" procedure... And now all those wonderful PTC based sanitizers that literally rip the lipid layers of microbes apart are at loose in your stomach. Think about it - Would you spray your cookware down with lysol (same active ingredients), wait for them to dry, and then have at it? Or would you have the common sense to rinse the chemical residue away in between? Your common sense here is completely wrong according to the procedural bean counters out there who don't believe any of us are capable of washing parts - Oh, and half the time they just aren't washed anyways - You don't want to know what goes on the rest of the time...

...That rant aside, IF you're going to use kitchenware, hit up your local thrift stores with the idea of disposability in mind. I love to cook, and as with my tools my pots and pans are dedicated - The GOOD ones are ONLY used for food, and are ONLY used by people who will treat them right - Everything else, screw it - I can replace it for pennies... So just prioritize - If you have some cookware that's crap, use it for whatever and don't ever plan on using it for anything else - If you need a pot for a one-off, pick it up for a buck or two at a thrift store... Helpful hint, coffee-maker carafes can be used directly on a gas stove as long as you're careful to minimize thermal shock...

EDIT - Formatting was screwed up, somehow the last paragraph wound up in the middle of the second one?


[Edited on 6-5-13 by Intergalactic_Captain]