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FID detector linearity response factors

Question asked by labproarw on Aug 26, 2020
Latest reply on Oct 15, 2020 by james_jenkins

I got a data sheet for my Agilent 7890 FID detector. The stated linear range is 10x7. This range I think should mean that from 1% down to 0.1 ppM the detector is linear for Tridecane. I figure concentration-wise in splitless mode - that works out to be 10-ug per 1-uL injection at the high end, down to 1-ng per 1-uL.

 

Over the years I have worked in labs that have injected neat samples with a split ratio and reported area percent values to production with FID. Given a one microliter injection, a hypothetical neat sample could be equal to a 1-mg injection. *Since 1-mg is 100x the maximum linear range amount for FID -- is there a valid argument that one should not report neat samples by FID and area percent, since the various components responses would not be linear? Specifically, the main assay peak linearity vs. the much smaller impurities. Questioning if main component peak would be under-reporting relative to impurities in high assay samples.

 

Give this a little thought in case my reasoning is flawed, and let me know if I am in error.

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