Flame Atmospheric Pressure Chemical Ionization Coupled with Negative Electrospray Ionization Mass Spectrometry for Ion Molecule Reactions

Abstract

Flame atmospheric pressure chemical ionization (FAPCI) combined with negative electrospray ionization (ESI) mass spectrometry was developed to detect the ion/molecule reactions (IMRs) products between nitric acid (HNO) and negatively charged amino acid, angiotensin I (AI) and angiotensin II (AII), and insulin ions. Nitrate and HNO-nitrate ions were detected in the oxyacetylene flame, suggesting that a large quantity of nitric acid (HNO) was produced in the flame. The HNO and negatively charged analyte ions produced by a negative ESI source were delivered into each arm of a Y-shaped stainless steel tube where they merged and reacted. The products were subsequently characterized with an ion trap mass analyzer attached to the exit of the Y-tube. HNO showed the strongest affinity to histidine and formed (M-H+HNO) complex ions, whereas some amino acids did not react with HNO at all. Reactions between HNO and histidine residues in AI and AII resulted in the formation of dominant [M-H+(HNO)] and [M-H+(HNO)] ions. Results from analyses of AAs and insulin indicated that HNO could not only react with basic amino acid residues, but also with disulfide bonds to form [M-3H+(HNO)] complex ions. This approach is useful for obtaining information about the number of basic amino acid residues and disulfide bonds in peptides and proteins. Graphical Abstract ᅟ.

Arc-Induced Nitrate Reagent Ion for Analysis of Trace Explosives on Surfaces Using Atmospheric Pressure Arc Desorption/Ionization Mass Spectrometry

“…Most of these NOIs are clearly observed (Figure B). In addition, a cluster ion, [HNO 3 +NO 3 ] − ( m / z 124.8), is formed, which is similar to dielectric barrier discharge ionization (DBDI), electrical discharge source, and flame atmospheric pressure chemical ionization (FAPCI) …”

“…In addition, a cluster ion, [HNO 3 +NO 3 ] − (m/z 124.8), is formed, which is similar to dielectric barrier discharge ionization (DBDI), 15 electrical discharge source, 19 and flame atmospheric pressure chemical ionization (FAPCI). 26 APADI Mechanism. The ionization patterns of TNT, HMX, tetryl, diethylene glycol dinitrate (DEGDN), ethylene glycol dinitrate (EGDN), RDX, PETN, erythritol tetranitrate (ETN), pentaerythritol trinitrate (PETriN), diazodinitrophenol (DDNP), and 2,4,6-trinitroresorcinol (TNR) were studied under APADI conditions.…”

Thin layer chromatography/desorption flame‐induced atmospheric pressure chemical ionization/mass spectrometry for the analysis of volatile and semi‐volatile mixtures

“…Therefore, the hot gas flow from a flame can be directed onto solid surfaces to desorb and ionize thermally stable chemical compounds such as drugs, explosives, and pesticides on different surfaces—a technique that has been named desorption FAPCI (DFAPCI) 46 . In addition, FAPCI combined with negative ESI was used to study a number of basic amino acid residues and disulfide bonds in peptides and proteins 47 …”

“…46 In addition, FAPCI combined with negative ESI was used to study a number of basic amino acid residues and disulfide bonds in peptides and proteins. 47 In this study, a DFAPCI-based TLC/MS was developed to characterize volatile and semi-volatile chemical compounds in standard solutions and plant extracts. A micro-flame (1 mm in length)…”