Chromatography Forum

Hi folks,

In our lab we routinely measure CH4, CO2 and N2O using an Agilent 6890 fitted with FID (+ methanizer) and an ECD. We use a haysepQ column for seperation and the output of the column switches between the two detectors. The system works very well for us.
We have someone in the lab who is wanting to take gas samples (in the field) from wastewater treatment systems and biogas digesters, store the gas in exetainer vials and then analyse them on the GC for the three above gases. from my experience with such samples, they are likely to contain H2S. This will just kill the catalyst in the methanizer (happened before, and we had problems removing H2S, think it sticks to metals?, anyway was a nightmare to resolve). So I'm not prepared to let the person run those samples as they are!
Question, would there be a way of effectivley removing H2S from the gas samples in the exetainers? perhaps adding some trap, before the exetainers are evaculated? Anyone have any experience in doing that? Or suggestions?
Cheers,
Nick

You should try Googling 'hydrogen sulfide removal". One such hit In got is http://onlinelibrary.wiley.com/doi/10.1 ... 4/abstract.

Another way around this problem is to install a valve to bypass the methanizer when the Hydrogen sulfide elutes from the column.

Gasman

Thanks for the reply gasman. Installing a valve would be the best solution, but that is currently not possible (world of academia is lacking a few funds). Will play around with some tests using a liquid trap (Fe/EDTA?) within the exetainer vials. Cheers, Nick

We have removed H2S from olefin samples using Lead Oxide pellets used for sulfur removal in our olefins unit. Our exercise was to demonstrate that the absorbent was working. It did not have an adverse effect on the chromatography.