Porous ion emitters—A new type of thermal ion emitter

The porous ion emitter is sintered onto the center of a conventional thermal ionization filament and an aqueous solution containing the sample wicked into this emitter. A new type of porous refractory material has been developed as a thermal ionization emitter that is an improvement over both direct filament and resin bead loading. The porous ion emitter is sintered onto the center of a conventional thermal ionization filament and an aqueous solution containing the sample wicked into this emitter. Application of the porous ion emitter to uranium is demonstrated to provide a utilization efficiency ranging between 1% and 2% across a sample size range of 0.2–10 pg, better than that achieved from resin beads and much better than that achieved with direct loading onto a filament. The technique improves sensitivity and reduces the chance of losing a high value sample when manipulating a single resin bead containing an entire sample.