Sensitive thin-layer chromatographic method for urine screening of barbiturates.

A simple and sensitive thin-layer chromatographic (TLC) method is described for the detection of barbiturates and other sedatives at therapeutic levels in the urine. The method consists of an extraction followed by TLC on a single plate in a solvent system which separates the barbiturates from most of the other drugs. The upper portion of the plate is sprayed with a new visualization reagent, N,2,6-trichloro-p-benzoquinone imine, followed by heating. The barbiturates appear as blue spots. This procedure is capable of detecting barbiturates at levels of 0.1 mg/dl in urine.