Formation of the [M−1]⁺ Ions of Methylindoles in APCI Mass Spectrometry

Figure 4

Effects of drying gas flow on the intensity of m/z 148 [M−1]⁺, m/z 149 M^+•, and m/z 150 [M+H]⁺ ions of 4-fluoro-3-methylindole studied on an Agilent LC-MSD equipped with the multimode ion source (nebulizer pressure, 40 psi; corona current, 2.5 μA).