Dielectric Barrier Discharge Ionization for Liquid Chromatography/Mass Spectrometry

Abstract

An atmospheric pressure microplasma ionization source based on a dielectric barrier discharge with a helium plasma cone outside the electrode region has been developed for liquid chromatography/mass spectrometry (LC/MS). For this purpose, the plasma was realized in a commercial atmospheric pressure ionization source. Dielectric barrier discharge ionization (DBDI) was compared to conventional electrospray ionization (ESI), atmospheric pressure chemical ionization (APCI), and atmospheric pressure photoionization (APPI) in the positive ionization mode. Therefore, a heterogeneous compound library was investigated that covered polar compounds such as amino acids, water-soluble vitamins, and nonpolar compounds like polycyclic aromatic hydrocarbons and functionalized hydrocarbons. It turned out that DBDI can be regarded as a soft ionization technique characterized by only minor fragmentation similar to APCI. Mainly protonated molecules were detected. Additionally, molecular ions were observed for polycyclic aromatic hydrocarbons and derivatives thereof. During DBDI, adduct formation with acetonitrile occurred. For aromatic compounds, addition of one to four oxygen atoms and to a smaller extend one nitrogen and oxygen was observed which delivered insight into the complexity of the ionization processes. In general, compounds covering a wider range of polarities can be ionized by DBDI than by ESI. Furthermore, limits of detection compared to APCI are in most cases equal or even better.

Pesticide analysis at ppt concentration levels: coupling nano-liquid chromatography with dielectric barrier discharge ionization-mass spectrometry

“…A comparison of the performances of ESI, APCI, and a helium plasma dielectric barrier discharge ionization (DBDI) source for pesticide analysis was reported by Gilbert-López et al [14], with the separation of 43 pesticides by LC and vaporization of the eluent (200 μL/min) by a modified commercial Ion Max TM API source [15] (Thermo Fischer Scientific). This low-temperature microplasma was already used in a similar configuration in combination with liquid chromatography for the analysis of environmental and food samples [14,16].…”

Theory and Practice of UHPLC and UHPLC–MS

“…These can be valuable for anyone undertaking analysis by any of these techniques because they often indicate what is the most sensitive and effective technique for a particular class of compounds. Among the classes of molecules or samples for which three API techniques have been compared head-to-head are these (by year): polyphenols (Parets et al, 2016), fungi (Cirigliano et al, 2016), petroleum (Huba et al, 2016), crude oil (Lababidi and Schrader, 2014), biofuels (Chiaberge et al, 2014), metalosalen catalysts (Słominska et al, 2014), benzimidazoles (Martínez-Villalba et al, 2013), metabolites in plasma (Tian et al, 2013), estradiol (Keski-Rahkonen et al, 2013, drug metabolites (Louw et al, 2012), Leishmania donovani promastigotes , fullerenes , hormones (Vilaró et al, 2012), polyaromatic hydrocarbons (Ghislain et al, 2012), epoxides , environmental and wastewater sample analysis for personal care product components and pharmaceuticals by DART and API techniques (Beißmann et al, 2011), cycloartane derivatives (Cicek et al, 2011), carotenoids , pharmaceuticals in wastewater (Garcia-Ac et al, 2011), illicit drugs in oral fluids , products of the Meerwein reaction with epoxides (Wu et al, 2010), lung cancer biomarkers , flame retardants (Mascolo et al, 2010), polar components by dielectric barrier discharge ionization and API techniques (Hayen et al, 2009), drugs and their impurities (Hommerson et al, 2009), dimers of 4-(methyl mercapto)-phenol (Wu et al, 2009), polymer additives (antioxidants, UV absorbers, and processing stabilizers) (Himmelsbach et al, 2009), estrogenic chemicals in wastewater (Lien et al, 2009), pentacyclic triterpenes (Rhourri-Frih et al, 2009, hydroperoxides from linalool and limonene (Nilsson et al, 2008), domoic acid (a neurotoxin) in shellfish (Pardo et al, 2007), polyaromatic hydrocarbons (Grosse and Letzel, 2007), plant melatonin, serotonin, and indole-3-acetic acid (Cao et al, 2006), fatty acids, MAGs, DAGs, and TAGs, …”

The Effects of Added Hydrogen on Noble Gas Discharges Used as Ambient Desorption/Ionization Sources for Mass Spectrometry

“…The chemicals used in this study were chosen to match previous studies [9,10,20,21] done with pure helium and hydrogen-doped helium. They included caffeine (Sigma Aldrich, Steinheim, Germany), diphenylamine (Brigham Young University chemical surplus, source unknown), anthracene (Spectrum Chemical Mfg.…”