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Styrene radical cations for chemical ionization mass spectrometry analyses of monoterpene hydrocarbons
Author(s) -
Spesyvyi Anatolii,
Španěl Patrik,
Sovová Kristýna
Publication year - 2019
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.8556
Subject(s) - chemistry , camphene , monoterpene , chemical ionization , myrcene , limonene , mass spectrometry , reagent , ion , styrene , ionization , chromatography , organic chemistry , analytical chemistry (journal) , copolymer , essential oil , polymer
Rationale Monoterpene hydrocarbons play an important role in the formation of secondary aerosol particles and in atmospheric chemistry. Thus, there is a demand to measure their individual concentrations in situ in real time. Currently, only the total concentration of monoterpenes C 10 H 16 can be determined by chemical ionization mass spectrometry techniques using reagent ions H 3 O + , NO + and (C 6 H 6 ) n +• without gas chromatographic separation. Methods The styrene cation C 8 H 8 +• was investigated as a reagent for chemical ionization of monoterpenes. The modified selected ion flow drift tube, SIFDT, technique was used to characterize the differences in product ion distributions between α‐phellandrene, α‐pinene, γ‐terpinene, β‐pinene, ocimene, sabinene, 3‐carene, ( R )‐limonene, camphene and myrcene. Results The monoterpene molecular cation C 10 H 16 +• is the main product (about 90%) for all isomers except ( R )‐limonene and camphene with an efficient channel of C 8 H 8 +• C 10 H 16 adduct formation and γ‐terpinene with unexpectedly significant product ions at m/z 134 and 135 corresponding to losses of H 2 and H. Conclusions Utilization of the styrene cation for the ionization of monoterpenes is beneficial due to the very low fragmentation of the product ions. Specific association product ions for camphene and ( R )‐limonene and fragment product ions for γ‐terpinene allow them to be distinguished from other isomers that produce mostly the molecular cation.