Headspace vials
Posted: Tue Jan 29, 2013 1:07 am
by Mac2
Has anyone investigated the difference between headspace vials?
Is it better to go 10 in 20 or 5 in 10?
Also, are screw caps as good as crimped caps?
Re: Headspace vials
Posted: Tue Jan 29, 2013 1:09 am
by Mac2
Also will a 3 mL loop fill give me 3 times bigger peaks than a 1 mL??
Re: Headspace vials
Posted: Tue Jan 29, 2013 9:28 pm
by chromatographer1
My paper in Analytical Chemistry June 1997 shows the effect of the same sample in 20, 10, and 3.35mL vials.
3mL loop fill will not give you 3 times bigger peaks. You will generally be unable to focus the sample and peaks will be 3 times as WIDE rather than as TALL, and resolution will suffer greatly.
You may wish to investigate SPME if you wish to lower your detection limit by 3-5 orders of magnitude.
There are inherent issues of greater variability with SPME, but rather than not detecting a 1 ppb peak, having a 15% RSD of a 1 ppb peak isn't so bad.
If you CAN discuss the particulars of your analysis I would be glad to offer assistance.
best wishes,
Rod