A comparison of accurate mass techniques for the structural elucidation of fluconazole.
Mass spectrometry plays a major role in the structural elucidation and characterisation of drug candidates and related substances. Accurate mass data allow the mathematical prediction of molecular formula of both precursor and fragment ions. In this paper, a comparison of the accurate mass data obtained for the fragmentation of fluconazole, an antifungal drug, by three different methods is made: electron ionisation (EI) using a magnetic sector instrument; electrospray ionisation (ES) using a Fourier transform ion cyclotron mass spectrometer (FTICRMS); and ES using a quadrupole-time-of-flight mass spectrometer (Q-ToF). It is clear from the data obtained that mass accuracy is not simply a function of instrument resolution. The subtle differences observed between collisionally activated dissociation (CAD) and sustained off-resonance collisionally activated dissociation (SORI-CAD) spectra are explained as a consequence of the excitation process. The advantages and disadvantages of the three techniques are discussed within the context of structural elucidation.
Thompson
Christine M
CM
Pfizer Global Research and Development, Ramsgate Road, Sandwich CT13 9NJ, UK. christine_thompson@sandwich.pfizer.com
Richards
Donald S
DS
Fancy
Sally-Ann
SA
Perkins
George L
GL
Pullen
Frank S
FS
Thom
Catriona
C
D015725:Fluconazole / Q000032:analysis* / Q000737:chemistry*; D013058:Mass Spectrometry / Q000379:methods*; D015394:Molecular Structure; D008970:Molecular Weight; D011786:Quality Control; D015203:Reproducibility of Results; D012680:Sensitivity and Specificity; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods
D015725:Fluconazole