Ion/molecule reactions performed in a miniature cylindrical ion trap mass spectrometer

Abstract

A recently constructed miniature mass spectrometer, based on a cylindrical ion trap (CIT) mass analyzer, is used to perform ion/molecule reactions in order to improve selectivity for in situ analysis of explosives and chemical warfare agent simulants. Six different reactions are explored, including several of the Eberlin reaction type (M. N. Eberlin and R. G. Cooks, Org. Mass Spectrom., 1993, 28, 679-687) as well as novel gas-phase Meerwein reactions. The reactions include (1) Eberlin transacetalization of the benzoyl, 2,2-dimethyloximinium, and 2,2-dimethylthiooximinium cations with 2,2-dimethyl-1,3-dioxolane to form 2-phenyl-1,3-dioxolanylium cations, 2,2-dimethylamine-1,3-dioxolanylium cations and the 2,2-dimethylamin-1,3-oxathiolanylium cations, respectively; (2) Eberlin reaction of the phosphonium ion CH3P(O)OCH3+, formed from the chemical warfare agent simulant dimethyl methylphosphonate (DMMP), with 1,4-dioxane to yield the 1,3,2-dioxaphospholanium ion, a new characteristic reaction for phosphate ester detection; (3) the novel Meerwein reaction of the ion CH3P(O)OCH3+ with propylene sulfide forming 1,3,2-oxathionylphospholanium ion; (4) the Meerwein reaction of the benzoyl cation with propylene oxide and propylene sulfide to form 4-methyl-2-phenyl-1,3-dioxolane and its thio analog, respectively; (5) ketalization of the benzoyl cation with ethylene glycol to form the 2-phenyl-1,3-dioxolanylium cation; (6) addition/NO2 elimination involving benzonitrile radical cation in reaction with nitrobenzene to form an arylated nitrile, a diagnostic reaction for explosives detection and (7) simple methanol addition to the C7H7+ ion, formed by NO2 loss from the molecular ion of p-nitrotoluene to form an intact adduct. Evidence is provided that these reactions occur to give the products described and their potential analytical utility is discussed.

Comparison of Functional Group Selective Ion–Molecule Reactions of Trimethyl Borate in Different Ion Trap Mass Spectrometers

“…Further, the use of well-characterized ion-molecule reactions has found a niche for the fast detection of specific compound classes [24,25]. In addition, ion-molecule reactions have been demonstrated to complement CAD in some cases where the latter method alone did not provide the level of characterization required [26,27].…”

On‐line monitoring of bioreductions via membrane introduction mass spectrometry

“…The real time on-line continuous monitoring of bioreductions is very desirable, particularly for the nearly instantaneous detection of bioactivity reduction of selectivity loss, which is a serious concern in bioreduction processes. The continuous efforts to develop very simple and cost-effective miniature mass spectrometers dedicated to SIM of a single or a few characteristic ions, such as the cylindrical miniature ion traps (Riter et al, 2003), will certainly contribute to the effectiveness of MIMS real-time monitoring of bioreductions.…”

Electron ionization and methane chemical ionization mass spectrometry study of some 2,2‐disubstituted 1,3‐dioxolanes, 1,3‐dithiolanes, 1,3‐oxathiolanes and 1,3‐dioxanes. Gas‐phase lactone and thiolactone formation

“…This process, where the ion-molecule transacetalization reactions occur, has come to be known as the Eberlin reaction. Also, analogous transacetalization reactions involving silanylium ((RO) 3 Si C ), 19 phosphinoylium (R 2 P C O), 20 dimethoxyboranylium (CH 3 OB C OCH 3 ), 21 dimethylaminoboranylium ((CH 3 ) 2 NB C N(CH 3 ) 2 ), 22 arenesulfenylium ions (ArS C ) 23 and benzoyl ions (ArC O C ) 24 have been studied The gas-phase formation of lactones from 2,2-disubstituted 1,3-dioxolanes and 1,3-oxathiolanes by isomerization of the ring and side chain followed by fragmentation has been the subject of only very few studies. 3,6 Dias et al 3 have studied the fragmentation behavior of some 2,2-disubstituted (R 1 CH 3 , R 2 (CH 2 ) n CO 2 C 2 H 5 , n D 1-5) 1,3-dioxolanes under electron ionization.…”