Chromatography Forum

I'm currently running an HP 5890A with capillary column and TCD for analysis of permanent gases (H2, O2, N2, CO, CH4, CO2, etc)

However, I would also be interested in analyzing for: H2O, H2S, SO2, SO3, and possibly even NOx's.

Obviously I'll need a different column, such as the Supel-Q PLOT (not sure if this can elute water?). If I use helium as a carrier gas, would it be possible to detect ppm or low % quantities of these gases with a TCD? Theoretically it looks possible, but I'd like to hear what others use for this analysis, both columns and detectors.

Thanks!

Supel-Q does elute water but it is not the best column to perform water measurement.

The other compounds you mentioned:

'H2S, SO2, SO3, and possibly even NOx's.'

are not measured reliably except with special columns designed to perform that measurement.

N2O is not a problem but NO and NO2 are.

best wishes,

Rod

The problem is that the reactive gases ( NO, NO2, H2S, etc ) can react with your detector ( if they don't react with something prior ), and the TCD is usually not sensitive enough, and poisons easily.

Traditionally, chemiluminescent detectors were used for NOx, rather than GC. I suspect that, these days, some of the gases can be more conveniently analysed by other techniques. If you only have to analyse a few samples, and sample size isn't an issue, Drager tubes give quick and dirty results, or submit sample to a environmental lab routinely doing the tests.

Bruce Hamilton