Setting up ASTM D5769 in MSD Chemstation

I have set up ASTM D5769 in MSD Chemstation ( Version G1701EA E.02.02.1431 ).  The calibration looks good and my checks generally look good.  But I have a slightly high bias on gasoline samples.  I think my uncalibrated C10 benzenes may be too high and I am wondering if I have that set up properly.  Does anyone know how to correctly set up the summing?  I am worried that it may be including C10 benzenes that I am already separately calibrated for.  Thank you!

  • It's been a while since I've set up D5769, but the uncalibrated group should not include any peak that is already identified in the calibration table.  You can run the QC sample that is defined in the method.  There are some C10 aromatics, but all peaks should be identified and nothing in the uncalibrated groups.

     

    Check also the time range defined in the calibration table for the uncalibrated groups.  For C10 aromatics, the end of the time range should be where 1,2,3,4-tetramethylbenzene elutes.

     

    (If my notes conflict with what is stated in the ASTM method, use that instead.  I don't have a copy of the current version and am referring to an older version of the ASTM D5769 method.)

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