by
GasMan » Tue Feb 05, 2019 3:33 pm
First, I am not a user of Perkin Elmer equipment, but I believe that your problem is common to all suppliers of TOGA analyzers. Basically, it is virtually impossible (in my opinion) to get vials with 0.0 ppm of O2,N2 and CO2. I assume that you are working to the ASTM method D3612 using method C. Look very carefully at table 5, where they give minimum detection limits for the gases. There is a footnote for O2, "Estimated from the H2 response". If you look at your chromatogram, I am sure that oxygen is well separated and the area can be integrated, so why must the response be "Estimated". To me, what they are telling you is that " As we cannot remove the oxygen completely from the vials we need to estimate the response from the hydrogen value".
Here is a bit more evidence. An Italian company, SEA Marconi, have a device to fill the vials with oil in an Argon atmosphere. Type the following into Google, "RT/HS-DGA" and you can download the user manual. If you read through this manual you will see that despite the Argon atmosphere, they advise you to fill a vial with the 'Argon atmosphere' and to subtract the amounts you find for O2 and N2 from your results.
Perhaps somebody can inform me why you need to measure these gases (O2 and N2) as all of the calculations that I have seen to ascertain the condition of a transformer do not include these gases.
Gasman