In the lab, we often want to measure out exact amounts of liquid. For small amounts - less than a ml, we use a pipetter. For larger amounts, we use reusable glass pipets. These we attach to what looks like a little gun connected to a vacuum pump to create suction, which allows us to pick up up to 25mls of liquid.
There are little signs outside some labs (not ours) with warning labels on them. Often, one of the warning lables is a cartoon of a head with a long glass/plastic pipet in it’s mouth, with a big circle/slash NO over it. NO MOUTH PIPETING!
But sometimes, sometimes you only want 3mls of liquid. And maybe it’s not really a DANGEROUS liquid. Something stupid. And you’re in a hurry, you just want to suck up 3mls, move it to your tube, and be done with it.
Even though we wash, sterilize and reuse our glass pipets, and sometimes a little something will get stuck in the tip, so that when you try to suck liquid up, it sticks a bit, then releases ALL at once.
This is OK if you’re using the vacuum gun. Not so much when you’re mouth pipetting because you’re in a hurry.
Wanna know what isopropanol tastes like?
not good.
ew.
You may be the first person I know who I consider SMART to MOUTH PIPETTE!
Maybe I need to reconsider my standards, ha!
CH3-CH2OH-CH3
Yummy. Working up to tert-butanol? Then you’re hard core…
I don’t do it that often. My pipet vacuum thing hasn’t been working all that great lately, and I just didn’t feel like walking to the other side of the room to get the cordless.
No fear. Won’t be doing that again ANY time soon.
Blech.
I started life as a clinical microbiologist, and so have a real phobia about mouth pipetting. However, I’m also fortunate to work at a biotech company, where those “pipet guns” sit on every bench and we can afford to purchase disposable sterile pipets. And actually dispose of them after a single use. Just be careful. It starts with isopropanol, but standards creep can lead to mouth pipetting 3M NaOH or acrylamide monomer (seen both done).
Hmmmm. Tasty! Well, at least it wasn’t bacteria…….
Ew!!
Oh and Lab Rat? Thinking about it with NaOH just makes me wince!
And Bunsen? The Mad Scientist rides again, soon as Honey sends my molds!
It tastes like a really bad martini, doesn’t it?
And a big “UGH”! on the NaOH. Good thing its small amounts we’re talking about, but still — the inside of the mouth is about the most sensitive place you can get to with your pants on.
Bad and wrong ESC!
You know, over here they always told us as undergrads that we should never mouth pipette, but here’s the thing, the very idea of it was completely alien, not to mention abhorent. They may have well said to us, “you must never eat dog shit” or something.
I am lucky in my lab, we do use disposables, which we fill with electronic handsets. That being said, we had a visiting researcher a few years back. A professor from NYU on sabatical, whom had not regularly been in the business end of a lab since the early 80s.
I was stunned into silence when I saw our visitor mouth pipetting bacterial cultures, and not just any cultures, our current Mu50 strain of vancomycin intermediate-resistant Staphylococcus aureus, or “MRSA-with-a-kick” as I like to call it.
Madness.