Same standard, different calibration curve


So, I bought 10 standard vials that contain multiple (>200) pesticides. I prepared 5 standards for my calibration curve mixing the 10 vial into the standard vials for my calibration level. After setting up the method, i found this difference: some compounds are perfectly fitted by the curve (r2= 0.99) while others have this particular trend with the 2nd-3rd-4th(?) calibration standard. same calibration vial of the "perfect" ones. standard made in the same way.

i thought that could be some interference between the >100 compounds that create this trend.

Other suggestion? Is there a way I can resolve this?

Perfect fitted compoundNot perfect fitted compound

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