Chromatography Forum

Can anybody recommend a capillary GC column for SO2 test ? (our GC can only connect to capillary column).

We need to test SO2 concentration in air stream in ppb level up to ppm level, using GC with FPD detector. The stream has moisture and is relative pure.

I tried regular general purpose capillary column but the results bounce around with +-15% error for a standard SO2. I also found that if I quickly introduce SO2 samples of fixed concentration into GC one by another, the following peaks will show higher intensity and areas.

I'm trying to fingure out what cause this error. It can only be column or tubing, as I'm using a Sulfnert sampling loop (100 ul) from Restek.

Thanks

dajiang,

Tell me why you are limited to a capillary column? Even splitless/split ports can be converted to packed ports if you are motivated? Regarding your variable results, it is highly likely that you are reacting with either the tubing or the column. If you do lots of injections, does the instrument become more consistent?

Best regards.

Thanks for reply.

We have to use the split injector to reduce the concentration of SO2.
Our test range is ppb level to 50 ppm level. And, FPD has narrow linear range.

Yes, I did inject many injections. But reproducibility is not improved. Low level SO2 is hard to work with. I also tried a PLOT porous polymer column, it is even worse than 0.5 um general MS column.

Thanks for any further suggestion. I'm considering GS-GasPro. But now sure if it is a right choice.

Can anybody recommend a capillary GC column for SO2 test ? (our GC can only connect to capillary column).

We need to test SO2 concentration in air stream in ppb level up to ppm level, using GC with FPD detector. The stream has moisture and is relative pure.

I tried regular general purpose capillary column but the results bounce around with +-15% error for a standard SO2. I also found that if I quickly introduce SO2 samples of fixed concentration into GC one by another, the following peaks will show higher intensity and areas.

I'm trying to fingure out what cause this error. It can only be column or tubing, as I'm using a Sulfnert sampling loop (100 ul) from Restek.

Thanks

SO2 sample must have free for even trace moisture. SO2+H2O= H2SO3---H2SO4.
You will loose SO2 sample and your Col. material may be damaged by absorption ore reaction with Col. adsorbant