Setting up a GC-TCD

[nappingpenguin]

I just recently found an old HP Series II 5890 TCD in the lab and am trying to get it hooked back up online for some simple gas analysis. I am looking at separating CO2 and CO in air samples, as well as a separate experiment doing H2 analysis in air I was thinking of using Helium as my carrier gas but I needed some advice about what type of column I should look into purchasing and where to find them since the machine is so old. From the research I have done, I believe I need a mol sieve 5A, but I am a little unclear. It also seems like I might be able to get buy with a silica gel column.

Side Note: I believe there may be some damage to the TCD detector. Is there any places you would recommend looking for replacement parts?

[chromatographer1]

Do not use MS5A as most commercial columns will not elute CO2 in a symmetrical peak in a reasonable time frame due to damaged packing.

(1-H2, 2-O2, 3-N2, 4-Methane, 5-CO, 6-CO2)
150°C 3m SS 2mm ID 60/80 MS5A Special
He carrier at 30cc/min. sample loop 750µL

Nitrogen containing
2500 ppm H2, 1000ppm O2 250 ppm methane, 375 ppm CO, 500 ppm CO2)

Here is a chromatogram of a 2mm ID column I packed using undamaged packing.




best wishes,

Rod

[chromatographer1]

Replacement parts for a TCD from HP?

It is called Agilent now.

Or you can replace their TCD with one from GOW-MAC or a helium ionization detector from VICI or AIC.

best wishes,

Rod

[chromatographer]

Rod,

How do you get undamaged packing? I didn't think you could run CO2 on mole sieve. I'm used to the damaged stuff!

nappingpenguin,

Alpha Omega at 5890.com has most parts for 5890's and 6890's.

[chromatographer1]

Well, golly that knowledge is the stuff I try to make a living from.

If you knew, would you give it away?

The CO and CO2 analysis can also be done on a Carboxen 1000 packed column, possibly on the capillary version also. But it does take time.

Usually CO with CO2 is done on a porous polymer column using hydrogen carrier, with a methanizer with a FID.

Rod

[aldehyde]

here is another 5890 parts supplier: www.csa-service.com

[chromatographer]

Well, golly that knowledge is the stuff I try to make a living from.

If you knew, would you give it away?

So, how do we pay you for this information or can we buy it direct from you? I certainly don't want to take away your source of income.

Best wishes

[AICMM]

nappingpenguin,

Agilent will have many, if not all, of your required parts. Otherwise, the already posted names are just a few of the possible sources for spare parts for 5890's. If you need more I can post some more. If you think it is just the filament, I have a company that repairs filaments in my files.

The big question, in my mind, is how low do you want to go with your TCD? If you want below about 100 ppm then you might struggle with the TCD. I would recommend using helium (or hydrogen) for the analysis of CO and CO2 (if you are going to stay with the TCD) and I would recommend argon or nitrogen for the analysis of the hydrogen. (Or, as Rodney noted, use an HID (Gow-Mac, Valco or AIC) and just use helium as the carrier and measure everything in one run.) (Standard disclaimer applies on my part here.) I have had good luck with ShinCarbon columns in this application and I am sure Carboxen would do the same. If you are talking high levels, then a TCD should serve you well although you will probably still have to swap the carrier gas. If you are talking high levels, like syngas, be aware of water as a component and its effect on any column you might choose.

Take a moment to search hydrogen on the Forum. There are lots and lots of posts about this type of application.

Best regards,

AICMM

[chromatographer1]

chromatographer

My email and other info is in my profile if you wish to chat.

Rod

[nappingpenguin]

Thanks for all your help you guys. I've decided to move forward with a Carboxene column from supelco. I'll let you know how it goes.