Two different Surface Sampling Methods have been developed for Advanced IMS. These methods are based on the desorption of the samples from the surface and subsequent detection by Advanced IMS with capillary inlet.
The desorption techniques are:
The Laser desorption - AIMS technique was tested for the detection of explosives. The explosives were detected directly from the surface without any further preparation. Measured sensitivities are 100 pg for TNT, 500 pg for RDX, and 1.8 ng for PETN.
The Surface Sampling Methods are suitable combination of high resolution, high sensitivity Thin Layer Chromatography with Advanced IMS.
After separation of the compounds by TLC, the TLC surface is sampled by the Laser desorption - AIMS without any further manipulation or preparation. The position of the laser is fixed and the TLC plate is moved in the desired directions by the motorized micro-positioning stage. The method was successfully applied to analyze the TLC plates containing explosives (TNT, RDX, PTEN, 2,4-dinitro toluene and 3,4-dinitro toluene), amino acids (alanine, proline and isoleucine), nicotine and diphenylamine mixtures.