Chromatography Forum

Hi,
I want to measure the following compounds in gas sample using GC/MS (Model GCMS-QP 2010S) equipped with Flame Photometric Detector (FPD):

1. Hydrogen Sulfide (H2S)
2. Methanethiol (MT)
3. Dimethyl Sulfide (DMS)
4. Dimethyl Disulfide (DMDS)

My GC column is BPX5 (5% Phenyl Polysilphenylene-siloxane, ID 0.25 mm, Length 30 m). I want to measure those components from gas sample. Now, I want to calibrate my GC. But, I have standard liquid solution. Does anyone have any suggestion for calibration and method?

bdhar2,

How thick is the film on your column? Unless it is a really thick film, I don't think you have enough column to do this separation. H2S will probably come out as, basically, an un-retained peak along with whatever other gases (read CO2) you have in the sample.

Having said that, if the liquid concentration is high enough, you can evaporate the sample in a cylinder and add balance gas to create a gaseous standard except that it is highly likely that your H2S is going to react (to a greater or lesser extent) with the cylinder. Best if you can buy a gas based standard for this application.

Best regards.