Chloroform analysis by HS-GC

Chromatography Forum: GC Archives: Chloroform analysis by HS-GC
Top of pagePrevious messageNext messageBottom of pageLink to this message  By Anonymous on Tuesday, May 7, 2002 - 03:40 am:

I am trying to analysis chloroform in the bulk material as volatile organic impurity.
I use Headspace-GC with FID.
But the problem is the sensitivity of chloroform is too low. As you know, PDE(permitted daily exposure) of chloroform is 60 ug/g. So if I dissolve 1g of bulk material in 10mL DMF, the concentration of solution should be 6 ug/mL.
At that concentration, the peak of chloroform is so small that I cannot believe quantitative analysis.

My GC condition is...
AT-1(0.32 x 30m, 5um)
Oven 35 degree, hold for 9 min ...
(Chloroform detected at 8.0 min)
Carrier gas : 24 psi(He)
HS condition: heat 85 degree, needle and transfer 90 degree...

How can I increase the sensitivity of chloroform?
Please help me...


Top of pagePrevious messageNext messageBottom of pageLink to this message  By Rodney George on Tuesday, May 7, 2002 - 05:39 am:

Dear anonymous,

Please review the following article:

Analytical Chemistry Vol 69 No 11 p2221-2223

Peaks from samples containing chloroform at less than 1ng per vial were detected. At 0.050 g (50ng) per vial the recovery based on the regression of samples spiked from 0.0005 g to 1 g was 99.2%. Methodology is linear up to 100g per vial and was performed on a Varian Genesis (Tekmar 7000) HS analyzer using an old Varian 3500 GC. Organic solvents such as DMAc or DMF reduce the recovery size by a factor of 3-9 but which remains linear over the range specified. Email me for any questions you may have. You have a lot of chloroform in your sample at 6g/mL. If you used 1L of your sample solution then 6ng of CHCl3 would be present in the vial. That is 10 times the amount detected in the above method. You should not have any problems performing this analysis as I am sure you can use more than 1L of sample per vial for your analysis. Heating time was 6 minutes at 85C. Sample size was 25 L. You should optimize your sample at 100 L, 0.600 g per vial, per the concentration you stated for maximum peak size.

Rodney George
Supelco R+D
rgeorge@sial.com


Posting is currently disabled in this topic. Contact your discussion moderator for more information.