Abstract: Methods and devices for generating ionized molecules for analysis in a mass spectrometer are provided. A device comprises a solid substrate having one or more edges for spray ionization, the substrate adapted for receiving extraction phase comprising molecules of interest. The solid substrate may comprise one or more indentations for receiving the extraction phase and desorption solvent. The indentation may extend to one of the edges of the substrate to channel the desorption solution to the edge for spray ionization. The solid substrate may comprise a magnetic portion for retaining magnetic extraction phase deposited thereon. The solid substrate itself may be free of any extraction phase prior to an extraction phase containing the molecules of interest being deposited thereon.