The present disclosure provides a novel system and method for evaporating and ionizing compounds comprising an LIAD source and an ionization source that operates at atmospheric pressure. This system is readily adaptable for use with most commercially available mass spectrometers. Ionization sources include Atmospheric Pressure Chemical Ionization sources (APCI) and Atmospheric Pressure Photo Ionization (APPI) sources. The ionization sources are positioned such that the analyte desorbing from the surface of the LIAD is fed into the ion stream produced by the ionization source and ionized analyte and ionized fragments of the analyte are fed into the sample inlet of a mass spectrometer. These systems allow for the mass spectrometric analysis of non-polar compounds that lack readily ionizable functional groups, such as saturated and unsaturated hydrocarbons and compounds with medium to low polarity, as well as hydrocarbon mixtures, such as petroleum.