This question is primarily related to stack testing data.
Whenever stack testing is being conducted and the parameter being measured is VOC concentration, it is often reported as ppm (as hexane) or ppm (as propane) and so on. My question is: what exactly does it mean physically to say ppm as hexane vs. ppm as propane or heptane and so on?
My apologies if it's a stupid question. I think my question probably gets into a little bit about how a flame ionization detector actually works.