• State Verified Answer
  • +1 person also asked this people also asked this
  • Replies 1 reply
  • Subscribers 117 subscribers
  • Views 639 views
  • Users 0 members are here
Related

Agilent Knowledge Portal

Find maintenance, best practice, and troubleshooting articles.

Agilent Knowledge Portal

Quantification of peaks

silencer2008

hi all, 

fairly new to the GC space so please bear with me.

We have an Agilent 7890B that we calibrate weekly for us, however there are some instances where the peaks despite being visible on the chromatogram are not quantified on the report for both standards and samples.  Is there something that can be done or some setting that i am missing for it to quantify peaks ? 


At the moment we go in and manually integrate each peak even after calibrating to obtain a result but we shouldnt have to be doing for each sample should we ?

We are using Open Lab CDS C.01.07 SR3

Parents
  • +1

    If the peak is being integrated but not identified, check that the peak window is wide enough.  In Chemstation, the noted retention time needs to be within the window.  The RT windows for all peaks can be set in Calibration Settings (under Calibration menu).  If you want to adjust the window for an individual peak only, select Calibration menu > Calibration Table Options > Identification Details.  This will change the columns in the calibration table.  The start and end of each RT window is defined by the "From" and "To" columns.

    If the peak isn't integrated at all, adjust the integration events, accessible via Integration menu > Integration Events.  Lower values for Slope Sensitivity, Area Reject, and Height Reject will integrate smaller peaks.  (Slope Sensitivity measures how much the slope of the baseline has to change before it is recognized as a peak.  Area and Height Reject will simply not identify peaks if the area or height are below those stated values.)  Also make sure there isn't an integration on/off timed event that is affecting the peak.

    I'd also suggest looking at the Collection of Chemstation Resources here on Community: Collection of OpenLab ChemStation Resources - Wiki - Chromatography Software - Agilent Community.  The Reference to Data Analysis Operation Principles guide provides a lot more detail on how the software does its work.

Reply
  • +1

    If the peak is being integrated but not identified, check that the peak window is wide enough.  In Chemstation, the noted retention time needs to be within the window.  The RT windows for all peaks can be set in Calibration Settings (under Calibration menu).  If you want to adjust the window for an individual peak only, select Calibration menu > Calibration Table Options > Identification Details.  This will change the columns in the calibration table.  The start and end of each RT window is defined by the "From" and "To" columns.

    If the peak isn't integrated at all, adjust the integration events, accessible via Integration menu > Integration Events.  Lower values for Slope Sensitivity, Area Reject, and Height Reject will integrate smaller peaks.  (Slope Sensitivity measures how much the slope of the baseline has to change before it is recognized as a peak.  Area and Height Reject will simply not identify peaks if the area or height are below those stated values.)  Also make sure there isn't an integration on/off timed event that is affecting the peak.

    I'd also suggest looking at the Collection of Chemstation Resources here on Community: Collection of OpenLab ChemStation Resources - Wiki - Chromatography Software - Agilent Community.  The Reference to Data Analysis Operation Principles guide provides a lot more detail on how the software does its work.

Children
No Data
Was this helpful?
Privacy Statement
Terms of Use
Contact Us
Site Help