An ion source (100; 400; 700; 1400) includes a plasma generator (104; 404; 1404) for supplying plasma at an ionization region proximate to a sample surface (120; 1120; 1220; 1320; 1420). The plasma generator applies energy that may be utilized for desorbing analytes from the sample surface as well as for generating plasma by which analytes are excited or ionized. Desorption and ionization/excitation may be controlled as individual modes. The ion source may be interfaced with an analytical instrument (118) such as an ion-based or optical-based spectrometer. A sample support (108; 708) may be provided, which may be capable of performing analytical separation.