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Effect of collision gas pressure and collision energy on reactions between oxygen and the negative molecular ion of tetrachlorodibenzo‐ p ‐dioxins in the collision cell of a triple ‐quadrupole mass spectrometer
Author(s) -
Kostiainen R.,
Auriola S.
Publication year - 1990
Publication title -
organic mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.475
H-Index - 121
eISSN - 1096-9888
pISSN - 0030-493X
DOI - 10.1002/oms.1210250502
Subject(s) - chemistry , ion , mass spectrometry , dissociation (chemistry) , torr , analytical chemistry (journal) , oxygen , kinetic energy , collision induced dissociation , triple quadrupole mass spectrometer , atomic physics , quadrupole mass analyzer , tandem mass spectrometry , selected reaction monitoring , physics , organic chemistry , chromatography , quantum mechanics , thermodynamics
Low‐energy reactive collisions between the negative molecular ion of a tetrachlorodibenzo‐ p ‐dioxin (TCDD) and oxygen inside the collision cell of a triple‐stage quadrupole mass spectrometer produce a substitution ion [M Cl + O] − , a phenoxide ion [C 6 H 4‐n O 2 Cl n ] −· , [M HCl] −· , and Cl − by which 1,2,3,4‐, 1,2,3,6/1,2,3,7‐ and 2,3,7,8‐TCDD isomers can be distinguished either directly or on the basis of intensity ratios. The collision conditions have an important effect on the relative abundances. Energy‐ and pressure‐resolved curves show that the ions formed by a collisionally activated reaction (CAR) process, i.e. [M Cl + O] − and [C 6 H 4‐n ,O 2 Cl n ] −· , are favoured by a high pressure of oxygen (3‐6 mTorr) (1 Torr = 133.3 Pa) and a low collision energy (0.1‐7 eV), whereas the ions formed by a collisionally activated dissociation (CAD) process, i.e. [M HCl] −· and Cl − , are favoured by high pressure and high energy. By choosing a relatively low collision energy (5 eV) and high pressure (4 mTorr), the CAR and CAD ions can be clearly detected.