Computer-aided identifications of thin-layer chromatographic patterns in broad-spectrum drug screening.

We have developed a systematic thin-layer chromatographic (TLC) technique for detecting and identifying drugs and drug metabolites on 10-cm-long silica-gel plates with organic binder (fluorescent indicator); a computer program (SPOT CHEK) assists in matching the data from a particular chromatogram with those obtained for known drugs recovered from serum, urine, or other specimens. The plates are developed in a single mobile phase. Visualization and detection reagents used to characterize unknowns include fluorescamine, ferric chloride/perchloric acid/nitric acid, Dragendorff, Marquis, Mandelin, and iodinated Dragendorff solutions, 254 nm ultraviolet light, and vapor from chlorine or hydrochloric acid. Detection limits of 5-200 ng per sample spot were obtained for drugs in the database. The computer program database is based on nine reaction responses plus the plate zone locations for 243 drug substances but requires entry of only one TLC property to generate a matching list. We ran the program with an IBM-compatible 386/486 PC using an MS-DOS operating system (version 6.2).