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Novel ionization reagent for the measurement of gas‐phase ammonia and amines using a stand‐alone atmospheric pressure gas chromatography (APGC) source
Author(s) -
Perraud Véronique,
Li Xiaoxiao,
Smith James N.,
FinlaysonPitts Barbara J.
Publication year - 2020
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.8561
Subject(s) - chemistry , amine gas treating , chemical ionization , mass spectrometry , gas chromatography , atmospheric pressure , reagent , triple quadrupole mass spectrometer , ammonia , analytical chemistry (journal) , chromatography , quadrupole mass analyzer , dimethylamine , ionization , ion , selected reaction monitoring , organic chemistry , tandem mass spectrometry , oceanography , geology
Rationale Contaminants present in ambient air or in sampling lines can interfere with the target analysis through overlapping peaks or causing a high background. This study presents a positive outcome from the unexpected presence of N ‐methyl‐2‐pyrrolidone, released from a PALL HEPA filter, in the analysis of atmospherically relevant gas‐phase amines using chemical ionization mass spectrometry. Methods Gas‐phase measurements were performed using a triple quadrupole mass spectrometer equipped with a modified atmospheric pressure gas chromatography (APGC) source which allows sampling of the headspace above pure amine standards. Gas‐phase N ‐methyl‐2‐pyrrolidone (NMP) emitted from a PALL HEPA filter located in the inlet stream served as the ionizing agent. Results This study demonstrates that some alkylamines efficiently form a [NMP + amine+H] + cluster with NMP upon chemical ionization at atmospheric pressure. The extent of cluster formation depends largely on the proton affinity of the amine compared with that of NMP. Aromatic amines (aniline, pyridine) and diamines (putrescine) were shown not to form cluster ions with NMP. Conclusions The use of NMP as an ionizing agent with stand‐alone APGC provided high sensitivity for ammonia and the smaller amines. The main advantages, in addition to sensitivity, are direct sampling into the APGC source and avoiding uptake on sampling lines which can be a significant problem with ammonia and amines.