Benzoyltropeine, an unusual substance in street heroin samples.

Benzoyltropeine, an isomer of tropacocaine, was found in samples of heroin seized in Florence in 1981. Since there were no analytical data on benzoyltropeine, it was difficult to differentiate this substance from tropacocaine. In an effort to make the differentiation easier, the authors tried out various techniques and found thin-layer chromatography and high-resolution gas chromatography to be the most suitable for this purpose. A specific identification of isomers of these substances was obtained by using nuclear magnetic resonance and gas chromatography/mass spectrometry techniques.