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

Figure 1

Full scan mass spectra obtained on an Agilent LC-MSD equipped with a multimode ion source in the positive ion mode (corona current, 2.5 μA; drying gas flow, 5 L/min; nebulizer pressure, 40 psi). (a) 4-Fluoro-3-methylindole; (b) 3-methylindole; (c) 2-methylindole; (d) 2,3-dimethylindole; (e) 3-indolyacetonitrile; (f) D-tryptophane.

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