Patent ID: 8486703

Claim:
A method of analyzing a chemical composition of a specimen, comprising: providing a probe comprising an outer capillary tube having an inner diameter H and an inner capillary tube disposed co-axially within said outer capillary tube, said inner and outer capillary tubes defining a solvent capillary and a sampling capillary in fluidic communication with one another at a distal end of the probe and h is a distance between a tip of said outer capillary tube and a tip of said inner capillary tube; contacting a target site on a surface of a specimen with a solvent in fluid communication with said probe, said solvent forming a continuous liquid microjunction across the surface of the specimen spanning at least the inner diameter H of the outer capillary tube; maintaining a plug volume proximate a solvent-specimen interface and within the liquid microjunction, the plug volume having a height less than h, wherein said plug volume is in fluid communication with said probe and wherein, during said maintaining step, a capillary ratio (h/H) exceeds 1.0; draining plug sampling fluid from said plug volume through said sampling capillary; and analyzing a chemical composition of said plug sampling fluid with an analytical instrument.