Figure 12:

Schematic of MasSpec Pen operation with (A) complete visualization of operating room use of the handheld device with integrated MS interface, (B) view of the handheld device alone showing (1) incoming water, (2) gas input, and (3) outgoing droplet capillary, (C) schematic of tissue sampling with the device showing the 3-D printed tip at three different times of sampling: t = 0 s showing initial solvent interaction, t = 2 s showing solvation of sample on the surface, and t = 3 s sequestering of sample into the outgoing droplet capillary (reprinted with permission from Zhang et al., 2017, copyright 2017 The American Association for the Advancement of Science).