title: Correlation of Ecom50 values between mass spectrometers: effect of collision cell radiofrequency voltage on calculated survival yield.
abstract: BACKGROUND
  The determination of the center-of-mass energy at which 50% of a precursor ion decomposes (Ecom(50)) during collision-induced dissociation (CID) is dependent on the chemical structure of the ion as well as the physical and electrical characteristics of the collision cell. The current study was designed to identify variables influencing Ecom(50) values measured on four different mass spectrometers.
  
  
  METHODS
  Fifteen test compounds were protonated using + ve electrospray ionization and the resulting ions were fragmented across a range of collision energies by CID. Survival yield versus collision energy curves were then used to calculate Ecom(50) values for each of these [M+H](+) ions on four different mass spectrometers. In addition, the relative recovery of the [M+H](+) ions of eight compounds ranging in molecular weight from 46 to 854 Da were determined at collision cell radiofrequency (RF) voltages ranging from 0 to 600 V.
  
  
  RESULTS
  Ecom(50) values determined on the four instruments were highly correlated (r(2) values ranged from 0.953 to 0.992). Although these overall correlations were high, we found different maximum ion recoveries depending on collision cell RF voltage. High-mass ions had greater recovery at higher collision cell RF voltages, whereas low-mass ions had greater recovery at lower collision cell RF voltages as well as a broader range of ion recoveries.
  
  
  CONCLUSIONS
  Ecom(50) values measured on four different instruments correlated surprisingly well given the differences in electrical and physical characteristics of the collision cells. However, our results suggest caution when comparing Ecom(50) values or CID spectra between instruments without correcting for the effects of RF voltage on ion transfer efficiency.
authors.affiliation: Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, 69 North Eagleville Road, Storrs, CT 06269, USA.
authors.forename: Dennis W
authors.initials: DW
authors.lastname: Hill
authors.forename: Clive L
authors.initials: CL
authors.lastname: Baveghems
authors.forename: Daniel R
authors.initials: DR
authors.lastname: Albaugh
authors.forename: Tzipporah M
authors.initials: TM
authors.lastname: Kormos
authors.forename: Steven
authors.initials: S
authors.lastname: Lai
authors.forename: Hank K
authors.initials: HK
authors.lastname: Ng
authors.forename: David F
authors.initials: DF
authors.lastname: Grant
mesh_terms: D001562:Benzimidazoles / Q000737:chemistry; D007477:Ions / Q000737:chemistry; D016014:Linear Models; D008956:Models, Chemical; D008970:Molecular Weight; D012015:Reference Standards; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods* / Q000592:standards*
chemical_list: D001562:Benzimidazoles; D007477:Ions; C031000:benzimidazole