Ionization Capabilities of Hydronium Ions and High Electric Fields Produced by Atmospheric Pressure Corona Discharge

Abstract

Atmospheric pressure corona discharge (APCD) was applied to the ionization of volatile organic compounds. e mass spectra of analytes having aromatic, phenolic, anilinic, basic and aliphatic in nature were obtained by using vapor supply and liquid smear supply methods. e vapor supply method mainly gave protonated analytes [A+H] + caused by proton transfer from hydronium ion H 3 O + , except for benzene, toluene and n-hexane that have lower proton a nity. e use of the liquid smear supply method resulted in the formation of molecular ion A · + and/or dehydride analyte [A−H] + , according to the nature of analytes used. e formation of A · + without fragment ions could be explained by the electron tunneling via high electric elds 10 8 V/m at the tip of the corona needle. e dehydride analytes [A−H] + observed in the mass spectra of n-hexane, di-and tributylamines may be explained by the hydride abstraction from the alkyl chains by the hydronium ion. e hydronium ion can play the two-roles for analytes, i.e., the proton donor to form [A+H] + and the hydride acceptor to form [A−H]

Solvent and Flow Rate Effects on the Observed Compositional Profiles and the Relative Intensities of Radical and Protonated Species in Atmospheric Pressure Photoionization Mass Spectrometry

“…A South American crude oil was dissolved at concentrations of 0.05, 0.175, and 0.300 mg mL –1 in mixtures of toluene and propan-2-ol for the DoE study. Polarity indices, solvent groups, pKa values, vapor pressures, boiling points, proton affinities, and ionization efficiencies − of the solvents used in this study are shown in Table S1.…”

Thermal desorption-ion mobility spectrometry: A rapid sensor for the detection of cannabinoids and discrimination of Cannabis sativa L. chemotypes

“…Firstly, the influence of the solvent (hexane) was evaluated immediately after smearing on the surface of the wipe sampling pad. Although hexane (672.5 kJ/mol) has a lower proton affinity than water (691.0 kJ/mol) [24], several signals that may interfere with the compounds of interest were detected. An example is shown in Figure S3, and as it can be seen, using hexane the CBC signal was not observed and only hexane signals were seen.…”

Poling of Glasses Using Resistive Barrier Discharge Plasma

“…One of the standard open-anode poling configurations is the so-called corona-poling with a needle-shaped anode [ 17 ]. Under a high voltage applied to the needle, plasma discharge between the anode and the specimen surface provides a large number of hydrogen/hydronium ions generated from atmospheric water vapor [ 18 ]. These ions penetrate into the glass, drift, and mostly compensate negative spatial charge left in the cation-depleted layer.…”