Fig. 5.

Parallel imaging MS/MS allows for MS¹ imaging simultaneously with MS² imaging. (a) Tandem MS was performed on the m/z 167 precursor detected in the ROIs (blue circles) corresponding to the fluoride hotspots on the transfected and ER-Tracker-labeled cell. No pixel binning was applied to this image. The scale bar is 10 μm. (b) The resulting product ion spectrum contained a fluoride ion at m/z 19, which is consistent with the product ion spectra of the m/z 167 ion produced by the ER-Tracker standard. (c) In control cells, fragmentation of the m/z 167 precursor yielded product ion spectra that lacked the fluoride ion peak at m/z 19.