Accurate Mass Measurements Using MALDI-TOF with Delayed Extraction

Matrix-assisted laser desorption ionization time-of-flight (MALDI-TOF) mass spectrometry is now an essential tool in biopolymer analysis. Sensitivity and mass range are unsurpassed, but mass measurement accuracy and resolution have been limited. With delayed extraction and a reflecting analyzer, mass measurements using MALDI-TOF can be made with an accuracy of a few parts per million (ppm). It is possible to distinguish Lys from Gln in peptides, and to determine the elemental composition of smaller molecules (mass 100–500). In database searching strategies, a smaller mass window, resulting from an increase in mass accuracy, greatly decreases the number of possible candidates. Mass measurement accuracy with errors less than 5 ppm is demonstrated on a mixture of 12 peptides ranging in mass from ca. 900 to 3700 Da. Mass measurements on 13 peaks in an unseparated tryptic digest of myoglobin gave results with an overall average error less than 3.5 ppm, with a maximum error of 7 ppm.

[1]  I. Mclaren,et al.  TIME-OF-FLIGHT MASS SPECTROMETER WITH IMPROVED RESOLUTION , 1955 .

[2]  M. Karas,et al.  Matrix-assisted ultraviolet laser desorption of non-volatile compounds , 1987 .

[3]  P. Thibault,et al.  Determination of the primary structure of peptides using fast atom bombardment mass spectrometry. , 1990, Biomedical & environmental mass spectrometry.

[4]  R. Whittal,et al.  High-resolution matrix-assisted laser desorption/ionization in a linear time-of-flight mass spectrometer. , 1995, Analytical chemistry.

[5]  A. Marshall,et al.  Resolution and chemical formula identification of aromatic hydrocarbons and aromatic compounds containing sulfur, nitrogen, or oxygen in petroleum distillates and refinery streams. , 1996, Analytical chemistry.

[6]  R. L. Hunter,et al.  High-accuracy molecular mass determination for peptides and proteins by Fourier transform mass spectrometry. , 1994, Analytical chemistry.

[7]  Stephen A. Martin,et al.  Delayed extraction matrix‐assisted laser desorption time‐of‐flight mass spectrometry , 1995 .

[8]  I. Papayannopoulos,et al.  The interpretation of collision‐induced dissociation tandem mass spectra of peptides , 1996 .

[9]  J. Klinman,et al.  A new redox cofactor in eukaryotic enzymes: 6-hydroxydopa at the active site of bovine serum amine oxidase. , 1990, Science.

[10]  R. S. Brown,et al.  Mass resolution improvement by incorporation of pulsed ion extraction in a matrix-assisted laser desorption/ionization linear time-of-flight mass spectrometer. , 1995, Analytical chemistry.