title: Correction of precursor and product ion relative abundances in order to standardize CID spectra and improve Ecom50accuracy for non-targeted metabolomics.
abstract: Quantitative biases in the abundance of precursor and product ions due to mass discrimination in RF-only ion guides results in inaccurate collision induced dissociation (CID) spectra. We evaluated the effects of collision cell RF voltage and collision energy on CID spectra using ten singly protonated compounds (46-854 Da) in an orthogonal acceleration time-of-flight mass spectrometer. The relative ion transfer efficiency, i.e. the relative amount of ions transferred through the ion guide at any particular RF voltage was shown to be dependent on the ion's m/z. We developed an algorithm to correct for the mass discriminating effects of RF voltage on CID spectra. The algorithm was tested for both precursor and product ions at multiple RF voltages and collision energies in order to ensure reliability. Our results suggest that compounds that generate major product ions with m/z values <150 have peak intensities that deviate substantially from their actual abundance. This has implications for small molecule metabolomics research, particularly for studies that rely on CID spectra matching methods for structure identification.
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Storrs, CT 06269 USA.
authors.forename: Ritvik
authors.initials: R
authors.lastname: Dubey
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Storrs, CT 06269 USA.
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Hill
authors.affiliation: Waters Corporation, 100 Cummings Center, Beverly, MA 01915, USA.
authors.forename: Steven
authors.initials: S
authors.lastname: Lai
authors.affiliation: Department of Statistics, University of Connecticut, 215 Glenbrook Road, Storrs, CT 06269 USA.
authors.forename: Chen
authors.initials: C
authors.lastname: Ming-Hui
authors.affiliation: Department of Pharmaceutical Sciences, University of Connecticut, 69 North Eagleville Road, Storrs, CT 06269 USA.
authors.forename: David F
authors.initials: DF
authors.lastname: Grant