Sciencemadness Discussion Board - Laboratory Tips and Tricks

Laboratory Tips and Tricks

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zenosx - 6-11-2012 at 18:39

I want to hear why sciencehideout found pipetting by mouth wasn't such a great idea....

Mailinmypocket - 7-11-2012 at 07:47

I want to hear why sciencehideout found pipetting by mouth wasn't such a great idea....

As far as I know, it isn't a good idea due to the fact that you can end up with chemicals in your mouth. He may have had a bad experience though- who knows!

zenosx - 8-11-2012 at 06:50

I want to hear why sciencehideout found pipetting by mouth wasn't such a great idea....

zenosx - 8-11-2012 at 07:24

Lol, that much is obvious. I imagine it wasn't a fun day to find out that "tip". Hopefully it wasn't anything too toxic or corrosive

Oscilllator - 10-11-2012 at 00:59

I find a great alternative to those plastic transfer pipettes to be straws. Straws can be bought from any supermarket by the hundred, and at negligible cost. To use a straw as a transfer pipette simply place it in the liquid, put your thumb over the top and pull it out again! Liquid will remain in the straw until you take your thumb off the top.

I use this method all the time, especially when I want to test the PH of a solution.

Stuck glass joints?

Mailinmypocket - 19-11-2012 at 08:39

I downloaded a PDF from Sigma-Aldrich called "Safe Handling and Care of Glassware" It's by Corning and has some interesting bits. One tip that was new to me was their method of separating stuck ground glass joints using soda water.

I tried to copy/paste from the document but it won't allow it, it's on page 6....

Attachment: Glass care and safe handling.pdf (1.3MB)
This file has been downloaded 1473 times

Dr.Bob - 19-11-2012 at 09:02

Quote: Originally posted by Oscilllator

I find a great alternative to those plastic transfer pipettes to be straws. Straws can be bought from any supermarket by the hundred, and at negligible cost. To use a straw as a transfer pipette simply place it in the liquid, put your thumb over the top and pull it out again! Liquid will remain in the straw until you take your thumb off the top.

I use this method all the time, especially when I want to test the PH of a solution.

I like to use a Pasteur pipette for removing enough to take a pH.

And the plastic transfer pipettes are not that expensive. I have cases of 500 available for $10 each, or a bagful for a $1.

ScienceHideout - 23-11-2012 at 07:57

Quote: Originally posted by zenosx

Lol, that much is obvious. I imagine it wasn't a fun day to find out that "tip". Hopefully it wasn't anything too toxic or corrosive

lol, no. It was just acetone- didn't taste very good, though, and it made parts of my mouth feel funny. I'd rather stick to water as a refreshing beverage.

Pyro - 20-12-2012 at 14:31

A microwave. You can use it for anything.
a few examples are: drying substances, I dry my KBr, KMnO4, ... with it, just half fill a beaker and put in on a 60s cycle, when thats done you usually have a perfectly dry solid
preheating liquids, When i re distill water I put the boiling flask in the microwave until just before it boils, then I put it on a hot hotplate and attach it to my condenser, that saves a lot of time.
when I wash a glass bottle and need it fast, I microwave it.

Magpie - 17-1-2013 at 15:00

Do you ever have a stuck ptfe stopcock? Just immerse it in ice-water. I have done this twice now and the stopcock frees in less than a minute.

At first this seemed counter-intuitive. But a little reflection on the coefficients of thermal expansion for borosilicate glass and ptfe showed why it works so well.

Glassware Shelves

radagast - 17-1-2013 at 16:48

I was tired of my glassware rolling off of my plastic shelf. To solve that issue, I turned the shelf upside down, which provided a wealth of valleys and ridges to securely hold each piece of glassware.

silvergrahm - 17-1-2013 at 17:56

I'd like to know what types of makeshift stir rods folks are using here. And also what you use for 2L plus vessels, either reaction or general storage.

CaliusOptimus - 17-1-2013 at 20:02

For the more technically inclined users, it's nice to have a few sticks of 1/4" round borosilicate rod around for making stir rods. You can heat the end up and flatten or shape it in any way, also you can make a rotating stirrer for high temp reactions where PTFE won't hold up.

Add a $50 oxy/propane torch and you can turn borosilicate tubing into tee fittings, capillaries, pipettes, reducers, and even weld small (~14/20) ground joints together to make adapters.

A great glass source: mountainglass.com

Magpie - 17-1-2013 at 20:33

Quote: Originally posted by Magpie

I often need a long stirring rod, something longer than the standard 10" variety, of which I have many. So I end up using my high temperature mercury thermometer as it is quite long. Realizing that this is poor practice I searched for a cheap source for a long stirring rod.

What I found is that you can order Simax borosilicate glass rod in several diameters from art glass suppliers for dirt cheap. You still have to pay the postage, however, which was about $5 for 3ea 20" rods.

I recommend FrantzArtglass.com

[Edited on 18-1-2013 by Magpie]

CaliusOptimus - 17-1-2013 at 20:50

Quote: Originally posted by Magpie

I recommend FrantzArtglass.com

[Edited on 18-1-2013 by Magpie]

Oooo...they are closer to me than mountainglass... I'm gonna place an order and see if the shipping is quicker

White Yeti - 18-1-2013 at 09:15

I didn't see this on the page, but a convenient way to bend aluminium tubing is to make a coil from aluminium MIG wire around it before bending. The coil will prevent the tube from caving in while bending.

Once the tubing gets stiff, it's good to anneal it with the help of a strong heat source. I use a stovetop covered with aluminium foil which easily reaches annealing temperatures, even for copper. A bunsen burner or an ordinary fire would also work for aluminium, but aluminium melts at a low temperature, so you have to be careful.

The bending and annealing is repeatable, so virtually any shape is achievable. This will also work with copper tubing, but higher temperatures are needed for annealing and the coil will have to be made from a stronger and thicker piece of metal than MIG wire.

franklyn - 18-1-2013 at 10:29

The way to bend metal tube is to fill it with something to keep it from collapsing ,
most commonly sand. Bending it hot will reduce the propensity for cold fracture.

.

Magpie - 29-3-2013 at 09:14

This posting nearly went to "Bad Days in the Lab" but instead turned out well. I dropped a mercury thermometer on the floor mercury end first when the cap came off its case. But instead of breaking and sending mercury all over the place, it merely bounced. This save was due to my son's gift of a rubber mat excessed from his place of work. It also saves my feet from standing on concrete when working in my lab.

Hexavalent - 29-3-2013 at 12:25

Very nice, Magpie! What kind of rubber is it composed of?

The carpet I have in my lab is not ideal for chemical, stain or fire resistance, but significantly reduces strain on my feet whilst standing and has also once saved my Hg thermometer.

What's the gas cylinder in the photo for....argon?

Pyro - 29-3-2013 at 12:29

my carpet is best for fire and chem resistance. it's brick

Hexavalent - 29-3-2013 at 12:29

A trifle annoyed at my continuous misplacement of stirbars, I recently attached one of these magnetic trays:

to the bottom of my hood for easy access, which allows me to throw stirbars at it and have them stick. They are inexpensive to buy, and I always know where to find stirbars when I need them.

Hexavalent - 29-3-2013 at 12:34

Since Easter is here, I have you a nice little tip: the trays that Easter eggs come on in shops/supermarkets are perfect for storing and holding RBFs of all sizes: I got about half a dozen different sizes the other day free of charge, and they are perfect for holding my 25 mL, 50 mL, 100 mL, 250 mL, 500 mL and 1L RBFs akin to the cork rings seen in professional labs.

Magpie - 29-3-2013 at 12:34

Quote: Originally posted by Hexavalent

Very nice, Magpie! What kind of rubber is it composed of?

What's the gas cylinder in the photo for....argon?

I don't know - just some medium soft black rubber. It was to be sold for exercise equipment but came with a small rip - so my son got it for nothing.

Yes, the cylinder contains argon. I can get that filled for ~$20.

Imakethings - 30-3-2013 at 06:59

'Redneck' chemistry trick.

Use fine or ultra fine sand in place of oil immersion bath, other bonus is that it holds heat better and won't really react much if you spill something on it. One of my favorite tricks that.

Hexavalent - 30-3-2013 at 08:35

Not to rain on your party, but various heating media have been discussed several times on the forum: a vast majority of members are quite aware of sand baths, and ironically a large proportion of people despise them

Sublimatus - 30-3-2013 at 15:15

Pro Tip: Get yourself one of those cheap little toaster ovens.

They're great for drying salts, powders, and glassware.

The best part is that it will save you the wrath of the Mrs., girlfriend, or mother. Nothing gets you on the shit list like putting chemicals?! in the oven. No amount of smooth talk will convince her that your covered magnesium sulfate has not just contaminated every meal that will ever be cooked again with radioactive, spooky toxins.

Mailinmypocket - 30-3-2013 at 17:11

Quote: Originally posted by Sublimatus

Pro Tip: Get yourself one of those cheap little toaster ovens.

They're great for drying salts, powders, and glassware.

The best part is that it will save you the wrath of the Mrs., girlfriend, or mother. Nothing gets you on the shit list like putting chemicals?! in the oven. No amount of smooth talk will convince her that your covered magnesium sulfate has not just contaminated every meal that will ever be cooked again with radioactive, spooky toxins.

Amen to that! My little 20$ toaster oven had worked miracles and saved me from kitchen related wrath

Burger patty papers

Mailinmypocket - 28-1-2015 at 13:44

Lots of grocery stores have these. Burger patty papers, pre-cut squares of wax paper, 1000 to a box for 2$. They're ideal for weighing chemicals, putting dirty scoops and spatulas on, covering various evaporating dishes etc. For the quantity and cost they are wonderful to have around to quickly grab when needed

[Edited on 28-1-2015 by Mailinmypocket]

Loptr - 28-1-2015 at 14:11

Quote: Originally posted by Sublimatus

Oh my god! Pretty much the exact response from my wife over drying magnesium sulfate in the oven.

I have also gotten speech that she will leave me if I blow myself up. I haven't touched any energetic materials whatsoever, but it is still a pain to have to explain myself and what I am doing.

A toaster oven sounds delightful.

Zephyr - 13-9-2015 at 11:50

1. Cover the openings of your clean glassware with parafilm or aluminum foil when not in use to stop dust from collecting in/on them

2. Having trouble getting that gunk out of your rbf? Add some fine sand and swirl with water.

3. Instead of buying overpriced cork rings for holding rbs, simply cut off an inch of appropriately sized pvc pipe.

aga - 13-9-2015 at 12:24

For RBFs i use a roll of masking tape.
< €1 and i get to use the tape as well.

The clingfilm idea is great.

Shame CHRIS25 doesn't visit here these days, he likes clingfilm.

Edit:

Toaster ovens are good for soldering up an all-Surface Mount PCB as well.

[Edited on 13-9-2015 by aga]

mayko - 20-6-2019 at 11:28

I came across this trick at work; I don't know how useful this is above the microliter scale, but it was too cute not to share.

A typical DNA extraction protocol includes a chloroform washing, in which the collected biojuices are mixed with chloroform (and usually phenol), which dissolves fats and proteins and such but leaves nucleic acids in the aqueous layer. As they are wont to do, the chloroform and water mixture form an emulsion, but a few minutes in the centrifuge break it easily.

The problem then is to collect the upper aqueous layer without the chloroform. We don't have tiny sep funnels, so this takes careful pipette work, and can lead to significant losses at a small scale.

But! We just started using a new protocol which involves something called "phase lock gel". This is basically just silicone grease, with a density intermediate to water and chloroform, and insoluble in both. A bit of this is added to the extraction mixture before centrifuging. When it pops out, the three substances have separated into layers: chloroform at the bottom, water at the top, and grease forming a convenient barrier between them. The upper layer can then be easily separated by pipette, or even just pouring!

Brand-name PLG costs $$$, but generic silicone grease can apparently be substituted. Here's some DIY tests with it:
https://bitesizebio.com/18944/diy-phase-separating-gel-clean...

Fantasma4500 - 26-8-2019 at 23:38

when youre trying to wash out solids from a beaker, instead of adding water and then turning it upside down, turn it 45* pointing downwards and with a spraybottle blow water into the beaker, the water coats the whole beaker, coalesces at some point, pulls everything out of the beaker.

to quickly dry up glassware acetone vapours can coalesce water, just opening a bottle of acetone and holding it to entrance you will see the water coalescing, acetone can then be used to fully dry it out, taking advantage of the high vapor pressure of acetone you can hold it under hot water

for drying out filtrate you fold the filte in half, dab it with paper. doing large scale stuff i used newspapers and basically this method, the paper helps to drag out the liquid over time

attaching a small computer fan to a beaker, preferably the fan pulls the air out of the beaker greatly enhances the evaporation rate, i removed i believe 230mL in an hour from a 1000mL beaker- for quicker evaporation you just increase surface area, glass pans that were originally meant for cooking food in oven works plenty fine.

now this is really just a ghetto filter, pressure filtration. ive thought about stepping this creation up a notch but it works well for small scale stuff. you just take a small plastic container, punch holes in bottom, throw in some wool, wetten it, put whatever you wanna filter into it after pressing cotton wool flat and then you with mouth pressure blow it through, you of course dont wanna use this device with toxic chemicals, but ive pulled half a litre of liquid through this very fast, within minutes.
bicycle pump might be used for this

for using butane as solvent, you just stuff it in freezer. comes out liquid

powdering viscous substances you stuff them in freezer, they become brittle. can be crushed with a steel rod with a twisting motion

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