Formation of positive product ions from substances with low proton affinity in high kinetic energy ion mobility spectrometry.

Considering the detection of polar substances with high proton affinity, classical ambient pressure IMS should reach better detection limits than HiKE-IMS. However, considering the detection of nonpolar substances with low proton affinity that are not detected, or only difficult to detect, at ambient pressure, HiKE-IMS would be beneficial.