11 replies to this topic

[slapolla]

I am making at 5 mg/mL soln of Tetracycline, and am using EtOH per our most recent Molecular Cloning manual...but I am having trouble getting all of the solid dissolved. Should I be using 70 % ETOH? Any thoughts/suggestions would be appreciated!!

[matiascs]

Ive made some Tet sol. a  couple of times....be sure to use an analytical balance, and dissolve it in absolute ethanol (100%)....and shake it up like theres no tomorrow...itll take a while but it will go into solution...
Do not autoclave...its ready for use....
Cheers

slapolla, on Mar 25 2005, 10:40 AM, said:

I am making at 5 mg/mL soln of Tetracycline, and am using EtOH per our most recent Molecular Cloning manual...but I am having trouble getting all of the solid dissolved. Should I be using 70 % ETOH? Any thoughts/suggestions would be appreciated!!

<{POST_SNAPBACK}>

[chandima]

i agree with matiascs. I do the same
chandima

[Julio-Claudian]

People,

Err... How do we know when to use water or ethanol? We have so much stocks here that I have yet to prepare any antibiotic solutions.

[mdfenko]

dreamchaser_jc, on Jan 29 2009, 09:54 AM, said:

People,

Err... How do we know when to use water or ethanol? We have so much stocks here that I have yet to prepare any antibiotic solutions.

you use that in which it is soluble and stable and will not interfere with your purpose.

[Julio-Claudian]

mdfenko, on Jan 30 2009, 12:53 AM, said:

dreamchaser_jc, on Jan 29 2009, 09:54 AM, said:

People,

Err... How do we know when to use water or ethanol? We have so much stocks here that I have yet to prepare any antibiotic solutions.

you use that in which it is soluble and stable and will not interfere with your purpose.

Alright, got it!

[molgen]

According to Lab-facts (Roche) make the stock in Et-OH and the dilutions in liquid culture.

[phage434]

I believe the confusion is that two forms of tetracycline are marketed, the compound, and its hydrochloride.  Tetracycline is soluble in EtOH, but not water.  Tet-HCl is soluble in water.  Dissolving Tet-HCl in 50%  EtOH is what we like, since it keeps the solution at -20C liquid.

[hanming86]

phage434, on Feb 13 2009, 08:42 AM, said:

I believe the confusion is that two forms of tetracycline are marketed, the compound, and its hydrochloride.  Tetracycline is soluble in EtOH, but not water.  Tet-HCl is soluble in water.  Dissolving Tet-HCl in 50%  EtOH is what we like, since it keeps the solution at -20C liquid.

And from my experience Tet-HCL is not as soluble in Ethanol compared to water. Tet-HCL in Absolute EtOH is quite crappy in term of solubility.

Edited by hanming86, 15 February 2009 - 08:34 AM.

[DNA]

Hi Guys,

I f we make tetracycline stock solution i absolute or 100% ethanol instead of water, dont u think that ethanol is dangerous/killer for E.Coli cells?

Yes i agree that not all tetracyline get dissolved , but i am still using it anyways by giving it a bit vortex.

Please advise.

Thanx.

[phage434]

The 1000x dilution you do when adding the stock to the medium makes the EtOH in the medium inconsequential.

[DNA]

phage434, on Mar 13 2009, 03:04 PM, said:

The 1000x dilution you do when adding the stock to the medium makes the EtOH in the medium inconsequential.

Thank you very much phage434. I did not know about it that we can do it.

We have got Tet-Hcl and   i would like to prepare it your way i.e 50% ethanol so it will remain in liquid form and no freeze thaw.

Cheers