Tandem time-of-flight mass spectrometry

• Published in: Methods in enzymology Vol. 402; p. 79
• Main Authors: Vestal, Marvin L, Campbell, Jennifer M
• Format: Journal Article
• Language: English
• Published: United States 2005
• Subjects: Amino Acid Sequence; Molecular Sequence Data; Peptides - analysis; Peptides - chemistry; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - instrumentation; Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization - methods
• ISSN: 0076-6879
• DOI: 10.1016/S0076-6879(05)02003-3

A new tandem time-of-flight (TOF-TOF) instrument has been developed by modifying a standard matrix-assisted laser desorption ionization (MALDI)-TOF instrument to make high-performance, high-energy collision-induced dissociation (CID) MALDI tandem mass spectrometry (MS) a practical reality. To optimize fragment spectra quality, the selected precursor ion is decelerated before entering a floating collision cell and the potential difference between the source and the collision cell defines the collision energy of the ions. Standard operating conditions for tandem MS use a 1-kV collision energy with single-collision conditions and increased laser power for ion formation. Hence, both high- and low-energy fragments are observed in MALDI TOF-TOF spectra. On standard peptides, sensitivities down to 1 fmol are demonstrated. On a mixture of two solution tryptic digests at the 25-fmol level, 23 spectra were sufficient to result in proper database identification.