title: Measurement of unimolecular decay in peptides of masses greater than 1200 units by a reflecting time-of-flight mass spectrometer.
abstract: Daughter ions from decomposition of [M + H]+ parent ions have been observed in a time-of-flight mass spectrometer fitted with an ion mirror. Unit mass resolution is obtained for parent ions of masses up to several thousand u when the mirror voltage is set at a value determined by the usual velocity-focusing criterion for parent ions. Under this condition the daughter-ion resolution in the low-mass range suffers. Considerable improvement is obtained when the daughter-ion spectrum is examined in several segments, with the mirror voltage optimized for each segment. The daughter-ion spectrum from decay of metastable [M + H]+ parent ions in Substance P is measured using this technique. Reasons are suggested for differences between the spectrum obtained and a spectrum for the same compound recently obtained using a tandem double-focusing instrument.
authors.affiliation: Physics Department, University of Manitoba, Winnipeg, Canada.
authors.forename: X
authors.initials: X
authors.lastname: Tang
authors.forename: W
authors.initials: W
authors.lastname: Ens
authors.forename: F
authors.initials: F
authors.lastname: Mayer
authors.forename: K G
authors.initials: KG
authors.lastname: Standing
authors.forename: J B
authors.initials: JB
authors.lastname: Westmore
mesh_terms: D004723:Endorphins / Q000737:chemistry*; D004743:Enkephalin, Leucine / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods; D011498:Protein Precursors / Q000737:chemistry*; D013373:Substance P / Q000737:chemistry*
chemical_list: D004723:Endorphins; D011498:Protein Precursors; D013373:Substance P; D004743:Enkephalin, Leucine; C025681:alpha-neoendorphin