FIG. 2.

Mass spectra of farnesylated intermediates. All spectra were obtained using an Applied Biosystems AP 4000 QTrap as specified in Materials and Methods. Intermediates were infused at a concentration of 2 pmol/μl in 80:20 ethanol-hexanes at a flow rate of 20 μl/min. Panel A shows the [RQ₃ + H]⁺ precursor ion (C₂₃H₃₄NO₃⁺; exact mass, 372.2) and the RQ tropylium ion (C₉H₁₂NO₃⁺; exact mass, 182.1). Panel B shows the [Q₃ + H]⁺ precursor ion (C₂₄H₃₅O₄⁺; exact mass, 387.2) and the Q tropylium ion (C₁₀H₁₃O₄⁺; exact mass, 197.1). Panel C shows the [DDMQ₃ + H]⁺ precursor ion (C₂₂H₃₁O₃⁺; exact mass, 343.2) and the DDMQ tropylium ion (C₈H₉O₃⁺; exact mass, 153.1). Panel D shows the [DMQ₃ + H]⁺ precursor ion (C₂₃H₃₃O₃⁺; exact mass, 357.2) and the DMQ tropylium ion (C₉H₁₁O₃⁺; exact mass, 167.2). Panel E shows the [DMeQ₃ + H]⁺ precursor ion (C₂₃H₃₃O₄⁺; exact mass, 373.2) and the DMeQ tropylium ion (C₉H₁₁O₄⁺; exact mass, 183.1; the base peak for this compound is highly collision energy dependent).