Sciencemadness Discussion Board

Anything to be wary of

Sulaiman - 7-6-2015 at 12:45

I was looking for test tubes and a test tube rack on eBay,
I bid on and won 6 Thunberg tubes in a rack http://www.ebay.co.uk/itm/Vintage-Wooden-Laboratory-Test-Tub...

in the listing it reads THEY WERE OWNED BY A "PROFESSER OF BIOLOGY"
ignoring the spelling above and the vagueness of the following question;

what 'special' precautions (if any) should I take when giving the tubes their first clean?

one clue is handwritten on the rack " J W Staph" which could mean Staphylococcus, Staphysagria or similar?
(or maybe J W was a staff member that also (like me) is 'spelling challenged')
Googling 'J W staph thunberg' didn't give anything definite.

incidentally, I do not have much use for Thunberg tubes at the moment,
I bid on a whim and unexpectedly won !

[Edited on 7-6-2015 by Sulaiman]

aga - 7-6-2015 at 13:09

Boil them.

All Life tends to stop above about 72 C after a few minutes.

Give it an hour of boiling and they'll be as biologically clean as anything ever is.



[Edited on 7-6-2015 by aga]

Sulaiman - 7-6-2015 at 13:11

nice and simple ...thanks !

aga - 7-6-2015 at 13:17

If you're paranoid, put a lid on the pan, or use a pressure cooking pot.

Most likely this has already been done before you bought them.

Zombie - 7-6-2015 at 13:26

Pressure cook them at 15PSI for one hour minimum.

Many common pathogens survive boiling temps. If you don't have access to an autoclave, a pressure cooker is the next best thing.

I wouldn't be too worried but I wouldn't lick them or see what they smell like just yet. My Spidey sense tells me that won't be good.

aga - 7-6-2015 at 13:39

Quote: Originally posted by Zombie  
Many common pathogens survive boiling temps.

Name One with any actual research to back that up ?

Perhaps Pasteurisation of Milk needs re-thinking, so this is Urgent !

Bot0nist - 7-6-2015 at 14:52

http://en.m.wikipedia.org/wiki/Endospore

Bacterial endospores can, IIRC.

Still, in most. cases boiling should be fine.


confused - 7-6-2015 at 21:48

i second the pressure cooker idea, if they've been used for bacteria culture.
(121 C at 15 psi for 15 minutes minimum)

If you can, pick up some autoclave tape at a medical supply or lab supply place, it changes colour/stripes when exposed to autoclave temperatures.

aga - 7-6-2015 at 23:31

http://en.m.wikipedia.org/wiki/Endospore#Formation_and_destr...

"Endospores are able to survive at 100 °C for hours, although the longer the number of hours the fewer that will survive"

"To kill all anthrax spores, standard household bleach .. 5% ... diluted 10:1 ... 10 minutes ... Higher concentrations of bleach are not more effective ..."

Bot0nist - 7-6-2015 at 23:40

I agree that there are chemical means of destroying endospores, much more efficiently than heat. Especially since most people would not boil their test tubes for "hours."

I HIGHLY doubt the OP has anything to worry about that that a good cleaning and solvent wash, maybe a boil, couldn't handle. Unless maybe the OP plans to prepare solutions to be used for intravenous application in the test tubes.

ChemistryGhost - 7-6-2015 at 23:43

Boil them in a pressure cooker with 95%+ pure isopropyl alcohol. Or freeze them with isopropyl alcohol and dry ice bath. Nothing can survive -78° C or lower! :cool:

Bot0nist - 7-6-2015 at 23:51

Quote: Originally posted by ChemistryGhost  
Nothing can survive -78° C or lower! :cool:


Unless the used and resold test tubes somehow contain non-terrestrial pathogens from... Europa maybe. Best play it safe and heat to a dull red glow, then follow with gamma sterilization. ;)

unionised - 8-6-2015 at 00:05

Quote: Originally posted by ChemistryGhost  
Boil them in a pressure cooker with 95%+ pure isopropyl alcohol. Or freeze them with isopropyl alcohol and dry ice bath. Nothing can survive -78° C or lower! :cool:


That would really piss off the people who store bacteria on dry ice.
Also, a pressure cooker full of flammable liquid is a spectacularly dumb idea.
If you don't have a pressure cooker (or don't want to use it for stuff that's not food) then bleach works.
All biology is based on proteins.
All proteins are amides
All amides are susceptible to the hoffman degradation when treated with hypochlorite.
So, as long as you use enough bleach, you will kill everything.

Fulmen - 8-6-2015 at 04:39

Quote: Originally posted by ChemistryGhost  
Nothing can survive -78° C or lower! :cool:

Really? Cryopreservation

And as unionsed says, filling a pressure cooker with a flamable liquid would take stupidity to a whole new level.

Sulaiman - 8-6-2015 at 04:43

There is no way that I will use the family pressure cooker for cooking potentially unknown pathogens.

Since bleach is much cheaper than 96% H2SO4 or 35% H2O2 (which were my first two thoughts) I will use that.

I could put them in a box with a gamma source,
but who knows what the little bugs lurking in the corners may evolve into !

Thanks for all the advice.

blogfast25 - 8-6-2015 at 05:23

Quote: Originally posted by aga  

Name One with any actual research to back that up ?



BSE Prions are incredibly resistant to traditional sterilisation methods:

http://www.bseinfo.org/deactivationofprions.aspx

aga - 8-6-2015 at 12:19

Quote: Originally posted by unionised  
So, as long as you use enough bleach, you will kill everything.

As per the wiki regarding antrax endo-jobbies, too high a concentration of bleach caused clumping and a LOWER rate of disinfection.

0.5% solution seems to be the way to go.

Lots of it maybe, just not a high concentration.

Edit:

To be completely OCD about it, Autoclave them for a month, heat them until the glass melts, hold there for a week, allow to cool, then bash the glass blob flat with a sledgehammer just in case any escaped.

Alternatively just boil them with a lid on for an hour and they'll be fine.

Biochemists tend to study Live samples.

[Edited on 8-6-2015 by aga]

confused - 8-6-2015 at 18:27

Here's a thought, why not use Fenton's reagent as a disinfectant

http://digitalcommons.unl.edu/cgi/viewcontent.cgi?article=11...