What kind of pipette would I need for this labwork and where can I buy one online?

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Med_Leviathan

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Let's say I have to take 2.4 to 24 mL of one substance and then add distilled water to make 100 mL solutions of different molarities. Insert question from the title here.

I thought other premeds would know since we're all doing the lab-monkey thing...
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I'm not sure where to get one online but for labs like this at school we had 25 mL, 10 mL, 5 mL, 2 mL, 1 mL graduated. Looks like you'll need a combination of those.
 
Your lab should provide the necessary equipment. Unless of course, it's a meth lab. Then just mouth pipette the anhydrous...it's just like siphoning gas out of a car.
 
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2.4 mL is a huge amount, you don't need a pipette for that. Get a syringe.
 
if you want any kind of calibrated pipette if can cost you from 280-600 for a single pipette... plus you would need to buy the tips as well. either way...2.4 is a huge volume think about using volumetric flasks for titrations.
 
Thanks for the posts so far...keep them coming. 👍

Here is one thing that I am confused about: I was told that the substance and the water should be mixed in the same volumetric flask, but there is no flask capable of measuring just 2.4 mL of a substance, is there? In that case, would you measure the 2.4 mL in a 25 mL graduated cylinder, place that in the flask, and then fill it to 100 mL with distilled H2O? Would you follow the same procedure if you need 24 mL of a solution rather than 2.4?
 
Med_Leviathan said:
Thanks for the posts so far...keep them coming. 👍

Here is one thing that I am confused about: I was told that the substance and the water should be mixed in the same volumetric flask, but there is no flask capable of measuring just 2.4 mL of a substance, is there? In that case, would you measure the 2.4 mL in a 25 mL graduated cylinder, place that in the flask, and then fill it to 100 mL with distilled H2O? Would you follow the same procedure if you need 24 mL of a solution rather than 2.4?
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No, you would use a graduated cylinder or pipette to measure 2.4 mL of solute into the 100 mL volumetric flask and fill it all the way to the 100 mL line with solvent. Now you have 100 mL of solution.
 
spicedmanna said:
No, you would use a graduated cylinder or pipette to measure 2.4 mL of solute into the 100 mL volumetric flask and fill it all the way to the 100 mL line with solvent. Now you have 100 mL of solution.
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"In that case, would you measure the 2.4 mL in a 25 mL graduated cylinder, place that in the flask, and then fill it to 100 mL with distilled H2O? Would you follow the same procedure if you need 24 mL of a solution rather than 2.4?"

Sorry, aren't these the same statements? 😕
 
Med_Leviathan said:
"In that case, would you measure the 2.4 mL in a 25 mL graduated cylinder, place that in the flask, and then fill it to 100 mL with distilled H2O? Would you follow the same procedure if you need 24 mL of a solution rather than 2.4?"

Sorry, aren't these the same statements? 😕
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Yes, they are. I read your post too quickly. I assumed that you were trying to measure 2.4 mL of solute with a volumetric flask.

Basically, you are trying to prepare/attain a certain molarity, which is moles of solute over total volume of the solution. The volumetric flask helps you do that by assuring you have the right total volume at the end.

I'd use a smaller graduated cylinder, however. 5 or 10 mL would work better. These smaller cylinders are better calibrated to handle smaller volumes.
 
spicedmanna said:
Yes, they are. I read your post too quickly. I assumed that you were trying to measure 2.4 mL of solute with a volumetric flask.

Basically, you are trying to prepare/attain a certain molarity, which is moles of solute over total volume of the solution. The volumetric flask helps you do that by assuring you have the right total volume at the end.

I'd use a smaller graduated cylinder, however. 5 or 10 mL would work better. These smaller cylinders are better calibrated to handle smaller volumes.
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Thank you so much for your help; it really does mean a lot to me.🙂
 
I forgot to mention, in case it wasn't immediately obvious, that I was referring, in my reply, to measuring solute volumes with the appropriately sized graduated cylinder or pipette. For example, it would be better to measure 2.4 mL with a 5 mL cylinder than with a 25 mL cylinder. Likewise, it wouldn't be a good idea to measure 24 mL with a 10 mL cylinder, since measurement errors compound.

Sorry if I wasn't clear before.

Good luck! 😉
 
There are pipette aids that can be used for larger volumes ( mls). The regular pipettes usually can pipet up to 1000 uL ( or 1 mL)....

But yeah, unless you want a really, really accurate measurement, I'd use a graduated cylinder.
 
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To add to the first post, there are pipete volumes of 1ml, 2ml, 5ml, 10ml, 25ml, and 50ml.

For absolute precision, I would take a 5ml pipete, fill it with 2.4ml of the solution, add that to a 100ml graduated cylinder, and then fill with DI H2O to the 100ml line. If you take a 5ml grad cylinder and fill it with 2.4 and then add it to the 100ml grad cylinder (as was previously suggested), you will have a higher degree of error because there WILL be solution left in the first 5ml grad. cylinder.

Just my 2 cents.
 
Try disposable stripettes - you can wash and reuse them if sterility isn't an issue. Non-sterile is cheaper too. They come in 2, 5, 10, 25 mL and are graduated. They are the most convenient I think. Assuming 2.4 mL is okay, as opposed to 2.400 mL. Order from Fisher. You can use a bulb. Or your mouth. My PI mouth pipets acrylamide as some sort of macho demonstration.🙄

I hate graduated cylinders for volumes less than 25 mL personally.

ps - if there's some sort of chromophore make a little extra and measure the actual concentration of your solutions if you get worried.
 
Med_Leviathan said:
Let's say I have to take 2.4 to 24 mL of one substance and then add distilled water to make 100 mL solutions of different molarities. Insert question from the title here.

I thought other premeds would know since we're all doing the lab-monkey thing...
Click to expand...

If the substance is homogenous and you know the purity and density, weighing the solution would be an option.

If you really need to pipette, they come in a variety of set volumes, and some come with graduations (like a graduated cylinder would have).
 
A Tree said:
Try disposable stripettes - you can wash and reuse them if sterility isn't an issue. Non-sterile is cheaper too. They come in 2, 5, 10, 25 mL and are graduated. They are the most convenient I think. Assuming 2.4 mL is okay, as opposed to 2.400 mL. Order from Fisher. You can use a bulb. Or your mouth. My PI mouth pipets acrylamide as some sort of macho demonstration.🙄

I hate graduated cylinders for volumes less than 25 mL personally.

ps - if there's some sort of chromophore make a little extra and measure the actual concentration of your solutions if you get worried.
Click to expand...

Pretty risky "macho demonstration"... Acrylamide is a carcinogen.... I wouldn't even try to inhale it in its dust form, let alone let it go anywhere close to my face
 
Med_Leviathan said:
Yeah, I stumbled across those Mohr pipettes on another site and I bought a set of 6
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I was wondering why no one suggested mohr pipettes before. Does your lab not have glassware on hand?
 
Well, that depends....how do you feel about a mouthful of potentially contagious biological fluids :meanie: or toxic chemicals? :laugh:

because I am not hardcore enough for mouth pipetting (or am I? 😱 )
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DropkickMurphy said:
*cough* Meth lab *cough*
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Seriously, sounds like someone running a meth lab or making some freebase coke. I have yet to see a lab class or any other form of research where you have to buy things as basic as a pipette on your own.
 
Pinkertinkle said:
Seriously, sounds like someone running a meth lab or making some freebase coke. I have yet to see a lab class or any other form of research where you have to buy things as basic as a pipette on your own.
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Mods, can we get an IP address on the OP so we can have him checked out by local LE? :laugh:
 
Pinkertinkle said:
Seriously, sounds like someone running a meth lab or making some freebase coke. I have yet to see a lab class or any other form of research where you have to buy things as basic as a pipette on your own.
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Maybe they were somewhere, but I couldn't find them. Perhaps you could come to my PI's physiology lab and help me out 🙄
 
Dude... chemistry at home? Any Phys lab and any PI wouldn't make you buy your own stuff. Anyway... for whatever it is that you are making... the cheapest way to do it is to use serological pipettes. They come in a variety of sizes... from 5 to 50 ml or more. They're just long plastic tubes, but they are very accurate... you prob used them in basic chem lab. You need a pump (cheap) or electric pipetaid (expensive) to use them. Go to fishersci.com and search for serological pipets.
 
i'm surprised your lab doesn't have spare or "broken" pipettes for your use. these can easily be calibrated for a small fee and work excellently yielding small error bars 🙂 btw eppendorf P2.5 P10 P20 P200 P1000 is the sexiest set on the market, but only if you have something like 800 bucks (comes with free tips and an pipette-shaped ball point pen to show off your nerdiness).
 
GreenCenter said:
i'm surprised your lab doesn't have spare or "broken" pipettes for your use. these can easily be calibrated for a small fee and work excellently yielding small error bars 🙂 btw eppendorf P2.5 P10 P20 P200 P1000 is the sexiest set on the market, but only if you have something like 800 bucks (comes with free tips and an pipette-shaped ball point pen to show off your nerdiness).
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Amen to that.
 
This is such a nerdy thread.
 
GreenCenter said:
comes with free tips and an pipette-shaped ball point pen to show off your nerdiness.
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Is anything really free these days? That's like throwing in a free stapler after you buy a car. 😀
 
BrettBatchelor said:
Only mouth pipette EtOH 🙂.
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ok, this might be a really stupid question, but if u were to drink some of the 190 proof etoh that they use in the lab to clean, what would happen, is it possible to get intoxicated from that???????
 
If it's not denatured (which will make you really sick and probably promptly vomit it right back up), yes. But the more important question is why in the name of Christ would you do that?
 
DropkickMurphy said:
Your lab should provide the necessary equipment. Unless of course, it's a meth lab. Then just mouth pipette the anhydrous...it's just like siphoning gas out of a car.
Click to expand...



:laugh: :laugh: :laugh:
That was awesome! 👍
 
DropkickMurphy said:
If it's not denatured (which will make you really sick and probably promptly vomit it right back up), yes. But the more important question is why in the name of Christ would you do that?
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not sayin i would do, just wonderin if its possible,

its like the idea of the distilled deionized milli-Q water that they use in the lab, its sooo clean and pure, it prolly tastes better than spring water, no?
 
BILAL said:
not sayin i would do, just wonderin if its possible,

its like the idea of the distilled deionized milli-Q water that they use in the lab, its sooo clean and pure, it prolly tastes better than spring water, no?
Click to expand...
Try it and find out.
 
EtOH is for the weak, I prefer benzene
 
Benzene is candy ass stuff.......hydrofluoric acid baby.... :laugh:
 
Which smells worse: Trizol Reagent or mouse poop?
 
Maybe until you die from hypocalcemia.
 
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