Thin-layer chromatographic plate scanner interfaced with a mass spectrometer

A device which scans a 1 x 10 cm TLC plate past a source of desorption energy has been developed. This scanner is interfaced to a quadrupole mass spectrometer by means of an isolation valve and a heated transfer line inserted into the direct sample inlet port. Chemical ionization reagent gas transports the desorbed compounds into the ion source. Two sources of desorption energy have been employed, a pulsed CO2 laser and a 150-W incadescent lamp. Sensitivity depends on the compound studied and the desorption energy available, with a minimum detectable amount of about 1 ng. Quantitation can be performed by using an internal standard with a precision of about 20%. Response with silica gel places is not linear. The method is non-destructive; plates can be rescanned or subjected to other detection methods.