Choice of thin-layer chromatographic systems for the routine screening for neutral drugs during toxicological analyses.

The efficiencies of fifteen thin-layer silica gel chromatographic systems for separating commonly encountered neutral drugs are compared. The discriminating powers of the systems are measured both individually and in combination. Chloroform-acetone (4:1) is found to be the best system. The combination of the ethyl acetate-methanol-ammonia (85:10:5) system with this gives the best pair of systems. A suitable sequence of spray reagents is also suggested. The chloroform-acetone (4:1) system is recommended as the best system to use when screening for both acidic and neutral drugs.