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Mass determination of human immunoglobulin IgM using matrix‐assisted laser desorption/ionization time‐of‐flight mass spectrometry
Author(s) -
Nelson Randall W.,
Dogruel David,
Williams Peter,
Beavis Ronald
Publication year - 1994
Publication title -
rapid communications in mass spectrometry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.528
H-Index - 136
eISSN - 1097-0231
pISSN - 0951-4198
DOI - 10.1002/rcm.1290080811
Subject(s) - chemistry , desorption , mass spectrometry , analytical chemistry (journal) , soft laser desorption , ion , kinetic energy , ionization , polyatomic ion , mass spectrum , matrix assisted laser desorption electrospray ionization , molecular mass , matrix assisted laser desorption/ionization , time of flight mass spectrometry , surface enhanced laser desorption/ionization , matrix (chemical analysis) , chromatography , thermal ionization mass spectrometry , organic chemistry , physics , enzyme , adsorption , quantum mechanics
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.