Area Ratio Custom field Empower 3

[David.Revlt]

Hi all.
I have got a question about the creation of a custom field over area ratio in Empower 3.
In my documentation I need to calculate the RSD% area ratio between a known peak and an internal standard peak in a sample type "Standard".

This is not a problem since indicating that one of the peaks is internal standard Empower 3 calculates Area ratio in the calibration, but, I also need to calculate RSD% area ratio between the same peaks but standard + brackets.

The problem comes because in my documentation the brackets are a type of sample "Control", and I want to avoid having to modify the sample type from "Control" to "Standard" in the brackets, since this way I would do a calibration line with the included brackets and in my documentation does not indicate this.

I have been trying to create a custom field of area ratio including the exact name of the peak Example: Area * EQ (Name, "peak A") / Area * EQ (Name, "peak B"), but this formula did not work.
Any help on how to write exactly the parameters in the formula?
Many thanks
Best regards

[EmpowersBane]

Im not sure I fully understand what you are looking for here but once a peak has been assigned as an internal standard in your processing method, for example against a main peak, then Empower will automatically calculate "Response" which is (Response of peak/Response of Internal Std)*Amount of Internal Std for your main peak in all samples, be they samples, standards or controls. Since the amount of internal standard in the standards is usually the same, response is basically a ratio of (Main peak response/Internal Standard peak response).

You don't need a custom field for this if you are just looking for the %RSD of response throughout the sample set- just add a summary table to your report method, add the fields you need (for example, Samplename, Vial, Channel ID etc and of course Response) then make sure to tick known AND internal under the peaks tab, then order by Date Acquired ascending, and in your data filter condition you can pick Sample Type of Control OR Standard depending on how you sign off your results. If you use one summary by all report to sign off all results in one go, then no filter is required. Then just add a %RSD summary to the Response field in the table.

If you need the result for a further calculation, then the custom field you need is a Peak, Real, Calculated custom field, set the Sample Type and Peak Type to all, search order to result set only and the formula is S%.%..%RSD(Response). For this to work you need to add the function Summarize Custom Fields as the last line of the sample set before you process the run. And of course label each relevant injection as S and something else eg S0101 S10 S01 etc. This will work then when you generate a result set. You need a label structure here that will work for both controls and samples and standards so your control could be S1, your standards could be S0101 etc.

P.S A really quick fix for your needs would be a peak, real, calculated custom field called Area_Ratio, coded as CCompRef1[Area]/CCompRef2[Area]. Assign your main peak in CCompRef1, the internal standard peak in CCompRef2 and add an RSD summary to this field in a report method, filtered as above.

[David.Revlt]

Hi.
You were right, with the filters of the report I got what I wanted, thank you very much for your help.
Best regards.