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Determination of a correction to improve mass measurement accuracy of isotopically unresolved polymerase chain reaction amplicons by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry
Author(s) -
Allison P.,
Muddiman David C.
Publication year - 2003
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.1111
Subject(s) - fourier transform ion cyclotron resonance , chemistry , mass spectrometry , analytical chemistry (journal) , ion cyclotron resonance , electrospray ionization , analyte , selected ion monitoring , ion , cyclotron , chromatography , gas chromatography–mass spectrometry , organic chemistry
The experimental determination of average mass by mass spectrometry is limited for large molecules due to the negative bias introduced by the natural distribution of isotopic abundances. This results in the measurement of the top‐of‐centroid (ToC) as opposed to the true centroid. We have developed a practical correction factor that is applied to the ToC measurement to largely remove the systematic bias introduced by nature. The correction factor is calculated easily using the average molecular mass (<100 kDa) of the analyte molecule and the full‐width half maximum resolving power (<3500) of the measurement. In addition, an approach to calculating resolving power is described that accurately predicts resolving power achievable for Fourier transform ion cyclotron resonance (FT‐ICR) mass analysis of large molecules. A combination of internal calibration with a dual‐electrospray source and application of the correction factor to average mass measurements improved the mass error from 192.5 to −35.0 ppm for a 44 kDa PCR amplicon. Copyright © 2003 John Wiley & Sons, Ltd.