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Solvent in BSTFA + 1% TMCS
Posted: Sun Feb 06, 2011 6:27 am
by Edde
In GC temperature gradient design, the initial oven temperature should be below the boiling point of the injection solvent. I wonder what the solvent in BSTFA + 1% TMCS (Supplier: W R Grace) is. I can't find its solvent in the reagent insert or from the internet.
Any expert knows the answer?
Please help.
Re: Solvent in BSTFA + 1% TMCS
Posted: Sun Feb 06, 2011 9:56 am
by Peter Apps
In GC temperature gradient design, the initial oven temperature should be below the boiling point of the injection solvent.
This is not true in all cases, and having the solvent condense onto the column can cause some quite dramatic peak distortions
I wonder what the solvent in BSTFA + 1% TMCS (Supplier: W R Grace) is. I can't find its solvent in the reagent insert or from the internet.
Surely it must be on the MSDS ?
Any expert knows the answer?
Please help.
Re: Solvent in BSTFA + 1% TMCS
Posted: Sun Feb 06, 2011 1:33 pm
by Don_Hilton
Eddie,
If the package insert listed no solvent, there is no solvent. And typically when you use MSTFA or MSTFA/TMCS it is used without solvent.
As Peter points out, you can check the MSDS for the specific product because all contents must be accounted for.
Re: Solvent in BSTFA + 1% TMCS
Posted: Sun Feb 06, 2011 3:19 pm
by Edde
Thanks.
"having the solvent condense onto the column can cause some quite dramatic peak distortions"
Peter, I thought the solvent can condense on the liner and cause solvent effect. Could you please elaborate more on the situation when solvent condensation is not desirable?
Peter and Don_Hilton, I will look up the MSDS for the content. Thanks.
Re: Solvent in BSTFA + 1% TMCS
Posted: Sun Feb 06, 2011 3:24 pm
by Consumer Products Guy
In that product the "solvent" is the BSTFA. The 1% (also available with 0% or 10%) can catalyze the reaction, typically instantaneous for hydrogens attached to oxygens, slower when hydrogen is attached to a nitrogen. We've used the 1% for decades, routinely. There are several vendors of this.
Re: Solvent in BSTFA + 1% TMCS
Posted: Mon Feb 07, 2011 7:49 am
by Peter Apps
Thanks.
"having the solvent condense onto the column can cause some quite dramatic peak distortions"
Peter, I thought the solvent can condense on the liner and cause solvent effect. Could you please elaborate more on the situation when solvent condensation is not desirable?
Peter and Don_Hilton, I will look up the MSDS for the content. Thanks.
Solvent condensation will cause problems if there is enough of it to form a lens across the column that then gets pushed along by the carrier gas. In a 0.25 mm diameter column this can happen with less than 0.2 ul. The problem is worse if there is a polarity mis-match between the stationary phase and solvent because then the solvent has less tendency to spread and more tendency to form lenses. Avoiding these solvent-stationary phase interactions is one reason to use a retention gap.
There is a pile of literature on solvent effects, inlets, large volume injections, retention gaps etc. Properly applied solvent effects can be very powerful, but in general I would say that using solvent effects introduces another set of (often poorly controlled) variables, and if you can avoid them, do so.
Peter
Re: Solvent in BSTFA + 1% TMCS
Posted: Mon Feb 07, 2011 10:43 am
by Edde
Appreciate your comment.