Corona Discharge Atmospheric Pressure Ionization Mass Spectrometry for Real Time Gas Analysis

Corona discharge atmospheric pressure ionization (API) source, developed in our lab, is coupled with a commercially available linear ion trap mass spectrometer for real time gas analysis. The H2O.+ (H2O) was observed and used to detect ethanol for the first time. The main reagent ions are m/z 36, m/z 37, and m/z 55 produced by corona discharge in humid nitrogen, and m/z 59 and m/z 76 are the main ions in humid nitrogen containing acetone. A series of aqueous solutions of various ethanol concentrations were analyzed by static headspacecorona discharge API MS. The detection limit was 2.4 × 10−7 g l−1 for the M + H2O.+, and 5.9 × 10−6 g l−1 for the MH+. The volatile compounds from gardenia flowers were analyzed by dynamic headspace-corona discharge API MS without sample pretreatment. The volatile compounds such as jasmine lactone, ocimene, and so on were detected continuously for nearly one hour. Corona discharge API MS, using many different vapors as ionization reagents, was proved to be potential applications for fast nondestructive analysis of biological samples.