The current TLC–MS interface is a second generation design for the solvent extraction of samples from a thin-layer plate. It differs from the surface sampling probe in that the whole sample zone, or that portion contained by the probe head, is eluted from the layer. A stainless steel plunger with a cut-ting edge is driven by pneumatic pressure (about 4–6 bar) through the layer to the backing support sealing and isolating the selected zone. The inlet capillary of the plunger is connected to a pump to deliver the extraction solvent (organic solvent or aqueous buffer organic solvent mixture at a flow rate of about 0.1–0.2 mL/min) to the sealed sample zone. The outlet capillary is connected via an inline particle filter to the ion source of the mass spectrometer or to a collection vial.