DIRECT ANALYSIS OF THIN-LAYER CHROMATOGRAPHIC SPOTS OF NARCOTICS BY MEANS OF DIFFUSE-REFLECTANCE FOURIER-TRANSFORM INFRARED-SPECTROSCOPY

The technique of diffuse reflectance Fourier transform infrared spectr ometry (DRIFT) as an in situ detection method was used for the qualita tive and quantitative analysis of drugs (heroin, cocaine and codeine) separated by thin layer chromatography. It was found that at a given i nterferometer throughput and detector sensitivity the quality of the s pectrum depends strongly in the type of the chromatographic thin layer used. A detection limit of approx. 2 mu g was attained on a microcrys talline cellulose thin layer with a dynamically aligned Bio-Rad Digila b FTS 60A/896 type interferometer and room temperature DTGS detector. A reliable qualitative analysis can be made with as little as 10 to 15 mu g drug per spot.