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Electrospray ionization Fourier transform mass spectrometry quantification of enkephalin using an internal standard
Author(s) -
Lorenz Sarah A.,
Moy Marie A.,
Dolan Anthony R.,
Wood Troy D.
Publication year - 1999
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/(sici)1097-0231(19991115)13:21<2098::aid-rcm759>3.0.co;2-o
Subject(s) - chemistry , electrospray ionization , mass spectrometry , fourier transform ion cyclotron resonance , electrospray , analytical chemistry (journal) , chromatography , pentapeptide repeat , fourier transform , ionization , ion , peptide , organic chemistry , mathematical analysis , biochemistry , mathematics
Fourier transform mass spectrometry (FTMS), long‐known for its capabilities in structural characterization of molecules, is an emerging tool in quantification, and quantification methods using external and internal standards with electrospray ionization (ESI) FTMS have recently been demonstrated. Here, commercial ESI‐FTMS is used to quantify the opioid pentapeptide methionine enkephalin using an internal standard. Linear working curves over three orders of magnitude are obtained using the internal standard, an improvement of one order of magnitude over the previous external standard ESI‐FTMS quantification method for enkephalins. Low coefficients of variation (generally <6%) are observed, and inter‐day and intra‐day assays are compared and found to possess similar linearity and precision. The high mass accuracy advantage of FTMS can be exploited to give molecular specificity. Efforts to improve mass accuracy using internal mass calibration generally provide mass accuracies within 2.5 ppm. Copyright © 1999 John Wiley & Sons, Ltd.