Simple question about response factor

[Perreman]

Hi!
I'm drawing blanks with my mind here. The question is: When having a response factor, do i multiply the area with it, or do i divide it?

Thanks!

[lmh]

I always like to think about the units in situations like this.
Is your response factor in signal/amount, or amount/signal? If it's signal per amount then:
Signal * (Signal / Amount) = Signal-squared per amount, which is a plain silly unit!
Signal / (Signal/Amount) = Signal / Signal * Amount = Amount, which is exactly what you want

The other way to look at it is to imagine a peak. If your response factor is 1000 units per pmole, then a 1-pmole injection would give you a peak with an area of 1000 units. Say you have 2 pmoles. That has to give 2000 units of peak area. So if the peak has an area of 2000, to get the answer "2 pmoles", what are you going to have to do, multiply or divide?

[Friederike]

RF = signal/amount : signal = RF x amount, amount = signal / RF

or

RF = amount /signal: signal = amount/RF, amount = RF x signal

[lmh]

but make sure you understand what you're doing rather than just memorising a formula. Otherwise, one day, you will get it wrong. (Sorry original poster, this is no reflection on you; it's just for others who might encounter this thread)