High Efficiency Photo-Induced Dissociation of Precursor Ions in a Tandem Time-of-Flight Mass Spectrometer

Abstract

High efficiency photo-induced dissociation (PID) has been demonstrated in a tandem time-of-flight mass spectrometer. This instrument focuses isomass ion packets to temporal and spatial dimensions similar to those of the focused laser pulses from a high power excimer laser. This high density overlap of photons and ions yields highly efficient fragmentation and also provides high resolution selection of specific precursor ion mass-to-charge ratio values. Using 193 nm photon excitation of the molecular ion of bromobenzene (m/z = 1561, fragmentation, collection, and PID efficiencies af 79%, 132%, and 104%, respectively, were obtained. Characteristic fragmentations of toluene, nitrobenzene, acetophenone, triethylamine, N,N-diethylformamide, N-methylacetamide, and cyclohexene have also been demonstrated.

Tandem time-of-flight (TOF/TOF) mass spectrometry and the curved-field reflectron

“…In 1993 two very similar instruments were reported, both using reflectrons in both MS stages, that is: an RTOF/RTOF configuration (Table 1). In the instrument described by Seeterlin et al [10], precursor ions were fragmented after deceleration by photodissociation with an ArF excimer laser, and then reaccelerated before entering the second reflectron. Cotter and Cornish described instruments with a floatable collision cell located between two dual-stage [11] and two single-stage [12] reflectrons.…”

In pursuit of resolution in time‐of‐flight mass spectrometry: A historical perspective

“…Tandem TOF's using ion mirrors in both stages were reported in 1993 (Seeterlin et al, ; Cotter & Cornish, ; Cornish & Cotter, ). Cotter and Cornish described both two dual‐stage ion mirrors in a tandem TOF, and two one‐stage (linear and “curved” field) ion mirrors in a tandem TOF.…”

An interleaved comb ion deflection gate for m/z selection in time-of-flight mass spectrometry

“…When pulsed laser photo induced dissociation ͑PID͒ is used as the fragmentation method, the laser pulse can be timed to interact with a single m/z value ion packet, thereby accomplishing selection. 4,5 However, the resulting product spectrum may overlap the portion of the normal ion spectrum having lower m/z values than the laser selected precursor as well as spectra due to metastable decomposition of other m/z values. [5][6][7] Elimination of low-mass ions or ions of little interest may be important to avoid detector saturation.…”