Development of an Atmospheric Pressure Chemical Ionization Interface for GC-MS

Abstract

A closed atmospheric pressure chemical ionization (APCI) ion source as interface between a gas chromatograph (GC) and a triple quadrupole mass spectrometer (QqQ-MS) was developed. The influence of different ion source conditions, such as humidity, make-up gas flow, and the position of the GC column, were investigated and determined as main factors to increase sensitivity and repeatability of the system. For a performance test under real conditions, the new APCI ion source was used for the determination of plant protection products in commercially available coffee beans from Vietnam. The ionization behavior was investigated and the majority of the analytes were detected as [MH]+, [M]+∙, or as characteristic fragment ions, which have been assigned to ion source fragmentation. The developed GC-MS methods are based on tandem MS (MS/MS) and revealed for the plant protection products limits of detection (LOD) between 1 and 250 pg on column and relative standard derivations for all compounds < 16%. The used ultrasonic solid–liquid extraction yielded recovery rates of approximately 60 to 100%. Residues of herbicide methyl esters, organophosphorus compounds, and organonitrogen compounds have been detected in the analyzed coffee beans.

Potential of atmospheric pressure ionization sources for the analysis of free fatty acids in clinical and biological samples by gas chromatography-mass spectrometry

“…3 part 1, all variances measured at the respective LLOQ were below 20%, except FA 16:1 and FA 18:3 which were at 23% each. Taking into account the standard deviations of APCI ion sources described in the literature with approximately 10 to 60%, this could be attributed primarily to the ion source [51]. In combination with the high stability of the PFB derivatives (Fig.…”

Application of Gas Chromatography Hyphenated to Atmospheric Pressure Chemical Ionization-Quadrupole-Time-of-Flight-Mass Spectrometry (GC-APCI-Q-TOF-MS) for Structure Elucidation of Degradation Products Based on the Cation in Pyr14TFSI

“…45,46 Since then, GC-APCI-MS was further developed and mainly applied for the analysis of different samples in the areas environment, food and toxicology. [47][48][49][50][51] Applying APCI, the molecular ion is mostly preserved and the accurate molecular mass can be measured when hyphenated to HR-MS systems. 52,53 Furthermore, precursor selection for APCI-MS-MS experiments is no compromise between sensitivity and selectivity, i.e., is a beneficial aspect for structure elucidation.…”

Hydrogen Plasma-Based Medium Pressure Chemical Ionization Source for GC-TOFMS

“…Due to increased fragmentation, the [M + H] + yield of α-pinene is 29%. For comparison, LODs of 2.5 pg and 3.5 pg on column for benzophenone were shown for a GC-APCI approach 13 and for a filament-based source coupled to a Q-TOF, 47 respectively.…”

“…Additionally, traditional EI driven CI sources often suffer from reduced filament lifetimes and residue build-up due to ionization source "fouling". 10,11 Many ion source designs for GC using chemical ionization with separated regions for reagent ion formation and analyte ionization, working in various pressure regions, were introduced since then, for example, atmospheric pressure chemical ionization (APCI) 12,13 and proton transfer reaction mass spectrometry (PTR-MS). 14 In this work, reagent ions are generated in a two staged process.…”

“…In many cases the collision rate at 1 mbar is not sufficient to collisionally disperse excess precursor ion energy which results in increased fragmentation. Additionally, traditional EI driven CI sources often suffer from reduced filament lifetimes and residue build-up due to ionization source “fouling”. , Many ion source designs for GC using chemical ionization with separated regions for reagent ion formation and analyte ionization, working in various pressure regions, were introduced since then, for example, atmospheric pressure chemical ionization (APCI) , and proton transfer reaction mass spectrometry (PTR-MS) …”