Correction Factor Scaling in OL from EZ Chrome

We are in the process of switching from EZ Chrome to Open Lab 2.5.  When we designed and implemented our method on EZ Chrome, we used a correction factor to multiply the Rf of the analytes in a certain matrix. The correction factor was average of all the response factors in fortified standards divided by the response factor in a certain matrix. If this was designed in EZ Chrome, would the correction factor still be applicable? or does EZ Chrome and OL integrate differently so we need to re-run our fortified standards to get a new correction factor in Open Lab?

  • Hello,

    It kind of depends on the version of EZChrom you are migrating from as to the differences you will see as some changes have been made to the EZChrom integrator over the versions. CDS 2.x does contain the EZChrom integrator as a choice in the processing method, this was done for compatibility to EZChrom methods. If the correction factor is relative between RF values, then it should be fine. However, the signals have changed between CDS and EZChrom so if the RF you are using was determined based on a specific signal unit that has changed. See the section, Differences in Peak Areas and Heights, starting on page 68 in the attached PDF. 

    Marty

  • Hi Marty, thanks for the quick response. When you say... "RF you are using was determined based on a specific signal unit that has changed", could you expound on that a bit more? We are using EZ Chrome 4.06 and migrating to OL 2.5

  • Hello,

    If you are using RF values and you do some sort of normalization, then the area unit change should not be an issue. In those cases, you are really using the RF values to compensate for response differences between compounds. If your RF is a hard value with no correction, for instance 5 area counts is 5ppm then the area change will affect that result. You would need to calculate new RF values in the CDS software by running known concentrations of your compounds or use the scaling values in the previous document to correct your current values based on the Area unit differencs. 

    Marty

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