Inherit calibration curve to compound groups

I am using MassHunter to quantitate GC data. I have 3 known compounds(monoolein, diolein, and triolein) and many suspects. A single internal standard, tricaprin, is used as an internal standard. The suspects are grouped into three Compound Groups (Mono, Di and Triglycerides). I used the inherit calibration curve from the advanced method menu and applied it to the suspects. I am using Compound Math to return the Sum of the Responses from the suspects to the Compound Group. When I analyze the batch the final and calculated concentrations are non-sensical for both the compound groups and suspects (I'm also using a ISTD Dilution, all my preparations are gravimetric).In addition, the ISTD Response Ratio is not calculated. I need this ratio, or at least the ISTD Response from the sample to perform a calculation. The Sum of the Response from the Compound Group are accurate and the arrow pointing to the concentration in the calibration curve seems accurate, so it seems to be doing something right.

Do I need to add a different column to add either the ISTD Response ratio or the ISTD Response for the sample?

Thanks

Matt

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• Hi  ,

The following method was created in Quant 10.2 based on your post to try and replicate what you are seeing. The "Standard Calibrator" is being used as a known compound with calibrators. Quantifiers "Suspect 1" and "Suspect 2" are included to compare against the Quantifiers "Suspect 1 inherit" and "Suspect 2 inherit", which both are inheriting the calibration curve from the "Standard Calibrator." Quantifier "Suspect Sum inherit" is the Response Sum of the Compound Group "inherit sum" and is also using the Standard Calibrator curve for concentration. An ISTD is being applied for each quantifier.

Here are the results for this batch:

Like you say, the "Suspect Sum inherit" response is a sum of the two suspect groups in this case, as expected. The calculated concentration for the "Suspect Sum inherit" compound does give the expected and reasonable result when plugging the RR value into the calibration curve and solving for the concentration. While I'm not showing it here, I did check that modifying the ISTD Dilution also worked as expected.

One thing to note is that you need to add the RR column to the Compound Results section of the batch table to see the values, instead of looking for it in the ISTD Results.

Is this how you've set up your method? If it is and the results still don't look right, can you please share what you are observing along with your method parameters? Additionally, what version of Quant are you using?

• I am using Quant 10.2

That does appear to be how I am setting up the method. For example the compound group Monoglycerides is inheriting the reference compound Monoolein

then I have compound Math set up for Monoglycerides as the Response Sum

However, I cannot see the ISTD Response Ratio and the Calc. and Final Concentrations are nonsense.

• The software is expecting that the response ratio (compound response/ISTD response) for the compounds is used to calculate concentrations, meaning that you should also be using an ISTD for your suspects and groups. Once you include and assign the ISTD to your suspects, the ISTD Response Ratio will be calculated and the concentrations will be as expected. When I remove the ISTD for the suspect compounds and the suspect groups (below), I also get results that reflect the concentration being calculated based on a response, instead of the response ratio.

• Thanks for the help. When I apply the internal standard to the suspects and groups I receive a validation warning that the ISTD and Target calibration tables number of rows don't match. If I apply the calibration table from the calibration samples the validation errors go away and I receive a warning saying that calibration levels are not defined when curves are inherited. I can analyze the batch at this point and the concentrations are calculated using the ISTD response ratio.

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• Thanks for the help. When I apply the internal standard to the suspects and groups I receive a validation warning that the ISTD and Target calibration tables number of rows don't match. If I apply the calibration table from the calibration samples the validation errors go away and I receive a warning saying that calibration levels are not defined when curves are inherited. I can analyze the batch at this point and the concentrations are calculated using the ISTD response ratio.

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