Chromatography Forum

good day!

when I think of quenching, I think of reduced absorption, though in this case im witnessing increased absorption, or perhaps not...

I calibrate my nitric oxide measurement with N2 diluted known bottle concentrations (<2000ppm NO)
when I measure diesel combustion exhaust, the sample is infused with H2O and CO2 (eg. 8%, and 14% respectively)

experimentally, I vaporize water and mix with known NO and CO2, and see that the NO measurement is significantly higher than my known value, proportionally to the concentrations of H2O and CO2

I can solve for this error linearly and my FTIR measurement is correct experimentally and when measuring exhaust
but I cant explain the phenomena I am seeing, any ideas?

thank you kindly!

perhaps I am witnessing static quenching by N2 in my NO/N2 bottles (2000ppm/99.8%)

that, in my opinon, would assume N2 would more readily statically quench than CO2 and H20, and that dont seem right

scratch that, peak broadening is my hypothesis

nitric oxide and carbon monoxide are likely victims of peak broadening, I assume is due to their narrow absorption
though
why and what is peak broadening, what would cause an absorption peak to broaden, not in the sense of increased width, but instead seemingly absorb more than what the concentration would entail

hmmmrrr....

matrix broadening?

anyone know the physics behind this?