Several operating and sample handling conditions were used to study their effect on spectral subtraction results using Fourier transform infrared spectroscopy. Purge rate, orientation of a heterogeneous sample and sample pathlength were varied to determine under what conditions and to what degree subtraction artifacts can be produced. To some degree, all of the conditions evaluated produced spectral subtraction artifacts although sample pathlength was found to have the greatest effect. Also under certain conditions, concentration differences taken from identical pathlength cells could not be totally nulled by subtraction manipulation.
