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Quantification of singly charged biomolecules by electrospray ionization fourier transform ion cyclotron resonance mass spectrometry utilizing an internal standard
Author(s) -
Gordon Eric F.,
Muddiman David C.
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(19990215)13:3<164::aid-rcm474>3.0.co;2-l
Subject(s) - fourier transform ion cyclotron resonance , chemistry , mass spectrometry , calibration curve , analytical chemistry (journal) , ion cyclotron resonance , electrospray ionization , detection limit , fourier transform , standard curve , selected ion monitoring , chromatography , ion , cyclotron , physics , gas chromatography–mass spectrometry , organic chemistry , quantum mechanics
The quantification of Cyclosporin A (CsA) and related biological compounds by various mass spectrometric techniques is well established. It is precisely this fact that makes the use of CsA particularly appealing as a model system in evaluating the quantitative properties of electrospray ionization coupled to Fourier transform ion cyclotron resonance mass spectrometry (ESI‐FTICR‐MS). Utilizing the internal standard methodology, we have generated a linear calibration curve ranging from 5–250 ng/mL CsA described by the equation y = 0.00503 x –0.00958, with a %RSD slope of 0.74% and a correlation coefficient ( r 0 ) equal to 0.999 2 (N = 30). The internal standard (200 ng/mL Cyclosporin G) was found to be necessary to establish the reported dynamic range, two orders of magnitude based on an experimentally determined detection limit of 2.4 ng/mL CsA, and also significantly improved the overall precision of the method. The data represented in the standard curve were collected as 1.05 s single acquisitions (512 K data points at an ADC rate of 500 kHz) and unapodized prior to the Fourier transformation of the time‐domain data. We report that full Hanning apodization has a statistically significant negative effect (F‐test at 95% confidence level) on the regression statistics of the curve (i.e. increasing the %RSD slope to 1.33%). Finally, we report that acceptable quantitative properties of an FTICR‐MS experiment can be realized as soon as the detection of a second isotopic beat for the targeted species is obtained. This should allow for the practical and effective coupling of on‐line separation techniques for quantitative analysis using ESI‐FTICR‐MS. Copyright © 1999 John Wiley & Sons, Ltd.