Chromatography Forum

I run a method using an internal standard. One of my system suit tests is to measure response factor for my active as per:

Area of active in working standard/(Area of internal standard in working standard * Concentration of active).

Is there a way for Empower to calculate the above. I already have Empower calculate the response (area of active/area of internal standard) but I don't understand the response factor calculation and what its supposed to prove?

I use Empower to calculate amount by setting my internal standard component against my active component in the component tab in processing method, then fill in sampleweights and dilution as normal. In my component editor i enter the value for Internal Std component as 1.00 for all unknowns becasue concentration is the same for both standards and samples.

Then i process my run (using the bracketing standards to calibrate) and my results are fine but i cant see the link between my response factor calculation as above and the amount calculation, can anyone explain it to me please?

Amount calculation:

(Area of active in sample*Area of Internal Standard*Concentration of Active in Working Standard* Dilution)/(Area of active in Working Standard*Area of Internal Standard in Working Standard*Sampleweight)

Using an internal standard is common in mass spec work to account for response drift. So as an example, due to the horrible samples I was analyzing last week for volatile organics, my instrument response was only 60% compared to when the calibration was run 2 weeks earlier. Because the response of both internal standards and the target analytes were low the calibration was still usable.