Mass determination of human immunoglobulin IgM using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry

R. W. Nelson, D. Dogruel, Peter Williams

Research output: Contribution to journalArticle

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Monoclonal human immunoglobulin IgM has been analyzed using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry. Using a matrix of sinapinic acid with a laser wavelength of 355 nm, positive ions with 2 to 6 charges were observed in the mass spectra. Two major molecular species were present. The molecular weights estimated from the multiply‐charged signals were found to decrease systematically with decrease in the charge state of the ion. This effect was determined to stem from the non‐linear influence of the initial kinetic energy of desorption on the final kinetic energy of the multiply‐charged species. A method of successive approximations, with the molecular weights and desorption velocities of the analytes as variables, was used to correct for these non‐linearities. Mean molecular weights for the two IgM species were found to be 939 000 ± 2000 and 982 000 ± 2000 Da. An initial desorption velocity of 565 ± 10 ms/s was determined for both.

Original languageEnglish (US)
Pages (from-to)627-631
Number of pages5
JournalRapid Communications in Mass Spectrometry
Issue number8
StatePublished - Aug 1994


ASJC Scopus subject areas

  • Analytical Chemistry
  • Spectroscopy
  • Organic Chemistry

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