Electrospray emitter assemblies for microfluidic chromatography apparatus

An apparatus for chemical separations comprising:

• a microfluidic substrate having an outlet aperture for outputting an eluent of a sample;
• an emitter assembly having a deformable end portion, an inlet near the deformable end portion to receive the sample eluent from the microfluidic substrate, and an electrically conductive emitter tube to emit a spray of the sample eluent, and a tubing assembly disposed around and coupled to the emitter tube, the tubing assembly comprising a first tube section having the deformable end portion, a second tube section abutting the first tube section end-to-end, and a third tube section spatially separated from the second tube section by a gap;
• an electrically conductive block disposed around a distal end of the tubing assembly and the emitter tube, the electrically conductive block having a bore through which the tubing assembly and emitter tube extend, with a tip of the emitter tube extending beyond a distal end of the electrically conductive block;
• and
• a force-applying unit applying a force to the emitter assembly that urges the deformable end portion into contact with the microfluidic substrate, the deformable end portion being more elastic than the microfluidic substrate so that the contact between the microfluidic substrate and the deformable end portion produces a substantially fluid-tight seal between the outlet aperture of the microfluidic substrate and the inlet of the emitter assembly.