Standard for 990GC

Hi, we just got a new Agilent 990 Micro Gas Chromatograph for our hydrotreating units and now we are trying to purchase a standard from vendors. One of the standard in stock from a vendor looks like a good fit for our requirement but the only concern is that there is a small amount of Argon(0.5%) in the standard.

Because the MS5A column of 990 GC is using Argon as a carrier gas, I was wondering if our 990GC could use such standard?  I don't think the 990 GC can detect Argon, so, if this standard could be used for the GC, should I exclude the Argon concentration from result to get a normalized concentration of components?

Any suggestions will be appreciated.

  • The argon won't be detected if you're using argon carrier.  The standard should work, but I would use the amounts of the other components as is (not normalized).  That would match the actual amounts in the standard.

    Also, remember to keep the sample pressure low, below 10 psi (70 kPa) if possible.

  • Hi Lance, thank you for your suggestions.

    The components in the standard are similar to our tail gas, but the concentration of components in the standard is very different from that in our tail gas, will this affect the accuracy of the analysis?  For example, the balanced hydrogen in the standard is ~40% but it might be over 90% in our tail gas. 

  • The calibration will be most accurate when it's close to the values in the standard.  The TCDs in the micro GC channels provide a linear response, so it should be okay.  You can also run 100% hydrogen and add that as another level in the calibration table.  That way the hydrogen calculation would use both points to determine its calibration curve.

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