(A) Desorption electrospray ionization (DESI) and (B) paper spray ionization, two of many ambient ionization methods. (C) Configuration of a miniature MS with a discontinuous atmospheric pressure interface and a miniature pumping system. (D) Mini 11 handheld MS that can be used for analysis of biological compounds from condensed phase samples.
DAPI: Discontinuous atmospheric pressure interface; HV: High voltage; RIT: Rectilinear ion trap.
(A, B, C & D) are reproduced with permission from [7,8,12,13], respectively.