Headspace constituents of opium.

The headspace of medicinal opium (Ph. Ned. 8) was analyzed by means of GC-FID, (+EI)-GC-MS (low and high resolution), and GC-FTIR. After olfactoric evaluation of the headspace sample by professional perfumers by the use of the GC-sniffing technique and after correlation tests with trained police dogs, more than 70 components were identified. With regard to the characteristic olfactoric properties of opium only one class of components, namely pyrazines, is of special interest. The synthetic mixture of 2-methyl-, 2,5-, and 2,6-dimethylpyrazine with 2-methoxy-3-isopropyl- and 2-methoxy-3-isobutylpyrazine was found to represent the original opium odour quite well.