We demonstrate that organic molecules embedded in sodium nitrate crystallites can be desorbed and detected as charged species using a picosecond, mid-infrared laser tuned to excite a nitrate stretching mode. We also detected all components of a mixture of carboxylic acid compounds, and carried out a preliminary quantitation of the mixture. The ionization mechanism and additional applications of the technique are discussed. (C) 2002 Elsevier Science B.V All rights reserved.