Fig. 7. Characterization of the CQA isomers with the precursor ions at m/z 353.0880 in DZT using precursor ion mobility: (A) extracted ion chromatography (EIC) of the m/z 353.0880 ± 5 ppm precursor ions including peaks 18 (blank trace), 20 (orange trace), 23 (blue trace) and 24 (green trace). (B) Overlaid mobility profiles of the m/z 353.0880 precursor ions of peaks 18, 20, 23 and 24; in addition, peaks 18, 23 and 24 among them further dissociated into valley-to-valley peaks, including mobility peaks 18a/18b, 23a/23b and 24a/24b, respectively. (C) MS/MS spectrum of the precursor ions at m/z 353.0880 for mobility peaks 18a, 18b, 20, 23a, 23b, 24a and 24b.