The Vespiary

The Hive => Chemicals & Equipment => Topic started by: Dragan on March 06, 2003, 01:25:00 PM

Title: Toulene
Post by: Dragan on March 06, 2003, 01:25:00 PM

What the different between Toulen Pa and Tolune HPLC. Toulen HPLC cost 80% more. Will swim get better results with HPLC?

Title: HPLC
Post by: pHarmacist on March 06, 2003, 01:32:00 PM

To apply High Performance Liquid Chromatography (HPLC) is a method (in this case) to obtain ultra-pure toluene. HPLC has many applications including separation, identification, purification, and quantification of various compounds...

I guess you are using toluene as a solvent in some meth related procedure.. HPLC-grade-toluene is a waste in that case...

Title: HPLC
Post by: Barium on March 06, 2003, 03:01:00 PM

P.a. stands for pro analysi (for analysis), analytical grade. You´ll se a long list of the impurities and how much of each. Toluene HPLC means that this solvent meant to be used for HPLC. It has not been purified by HPLC at all. HPLC is not for purification. It´s a analytical method.

What would you need the toluene for? Is it a reagent or solvent? If it´s a reagent then you want a purer grade. To be used as a common solvent, go for the cheapest possible.

Title: Thank you Barium
Post by: pHarmacist on March 06, 2003, 03:32:00 PM

I thought that it was purified by HPLC.

But:

>HPLC is not for purification.

Isn't it? I thought that HPLC could be used for purification as well..

Title: HPLC toluene
Post by: Rhodium on March 06, 2003, 04:01:00 PM

Preparative HPLC is possible, but it is seldom used even in research, as it it slow and you can only push through a certain number of milligrams a day in such a machine.

HPLC toluene is toluene fit for use as mobile phase when running other things through the column.

Title: Preparative HPLC is possible, but it is seldom
Post by: foxy2 on March 07, 2003, 05:43:00 AM

Preparative HPLC is possible, but it is seldom used even in research, as it it slow and you can only push through a certain number of milligrams a day in such a machine.

Actually it is quite commonly used for the purification of large bioactive proteins.  Even at production scales, protiens like IGG has a HPLC purification step.  I've seen pics of 0.5 meter diameter HPLC columns.
Check this out

http://www.lcgceurope.com/lcgceurope/data/articlestandard/lcgceurope/202002/19103/article.pdf (http://www.lcgceurope.com/lcgceurope/data/articlestandard/lcgceurope/202002/19103/article.pdf)

They even have continuously running HPLC systems.  It involves a series of coulmns and valves that can bee switched such that the separation is continuous.  I'm not sure if there are any actually in a pharmaceutical production process. Probably not because of the validation and cleanliness issues of such a system.  Plus batch processing is pretty ingrained in the pharmaceutical field.

Title: HPLC
Post by: Kinetic on March 07, 2003, 10:59:00 PM

A general HPLC solvent question then:

I remember reading that Zealot uses chromatograph grade solvents for water sensitive reactions, and said they didn't need to be dried because they were already dry enough. Could this be possible, even for highly sensitive compounds such as Grignards? I can get some HPLC solvents quite cheap, and would much rather use HPLC grade ethers and other solvents (DCM is particularly reasonable  :) ) than the ridiculously expensive 'anhydrous grade'.

Title: I can get some HPLC solvents quite cheap, and...
Post by: foxy2 on March 07, 2003, 11:26:00 PM

I can get some HPLC solvents quite cheap, and would much rather use HPLC grade ethers and other solvents (DCM is particularly reasonable  :)  ) than the ridiculously expensive 'anhydrous grade'.


Probably, as long as the bottle is unopened.  If I was needing anhydrous reagents I would just pick up some molecular sieves and bee sure they are dry.  If you want to get even drier there are refs in tfse and at rhodiums page which detail the appropriate drying agents for various solvents(ie P2O5 ect).  Molecular sieves are the cleanest and easiest general drying agent.

Title: Thought so
Post by: Kinetic on March 08, 2003, 12:04:00 AM

Thanks foxy, that was what I was expecting to hear. If I was going to perform a Grignard I think I'd still dry the solvent using traditional methods, at least the first time. I had just wondered if 'HPLC grade' products had to meet a certain specification (and therefore a maximum water content), in the same way USP grade products must meet the standards set.

Title: foxy: I was referring to organic synthesis.
Post by: Rhodium on March 08, 2003, 11:13:00 PM

foxy: I was referring to organic synthesis. For the purification of proteins and other enzymes in small quantities, most any method is used, even electrophoresis. But you still only do it in microscale.