Chromatography Forum

Hello,

I've had a client enquire about the possibility of analysing gas samples. On-line gas analysis has revealed concentrations of HCl up to 1000 ppm and Cl up to 5000 ppm. The object of the GC analysis would be to quantify CO2, CO & N2O concentrations in the gas sample. Would this level of HCl and Cl concentration cause issues for the column? On googling, I've found various suggestions for using column guards and backflushes to mitigate against corrosive gases, but little quantification as to what concentration of corrosive gases is a problem.

We have a Molesieve 5A packed column and an Agilent GasPro (113-4362).

Does anyone have any further suggestions on how best to approach this application? Are these concentrations too low to be concerned about? Would dilutions of the sample gas or other mitigations help?

Thanks!

As this is a client situation, I assume it's their method...

I'd file this under "try it and see". In other words, it will work fine, until it doesn't. It may be a new column every few samples, or every few months. Either way, I'd build into your contract that you'll be buying new columns as the old ones fail SST, and you'll obviously be passing those costs along.

Sophie180,

Is this a micro GC or a large GC? If a micro, I would be freaked by wiping out the injectors more so than the columns. And then, repair is a new module for 12-14K. I wouldn't do it, you could not pay me enough.

If this is a full scale GC, then the PP column in front of the sieve whould hold up the water (and probably the chlorine - I would need to look harder....) and the sieve should be okay. If the sample and your carriers are dry, you should be able to do this. It is done with process GC's for example.

Best regards,

AICMM