Extraction and analysis of different Cannabis samples by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry.

A headspace solid-phase microextraction combined with GC-MS method was developed for the extraction and analysis of cannabinoids from Cannabis samples. Different commercially available fibres were evaluated; polydimethylsiloxane 100 microm was selected as the most efficient one. In order to enhance sensitivity and reduce analysis time, the sampling temperature was studied and it showed that extraction should be performed at a high temperature (150 degrees C). In relation with the high lipophilicity of cannabinoids, a relatively long desorption time (3 min) was necessary to ensure a total transfer from the fibre into the injection port of the gas chromatograph. The method was finally applied to the extraction of Swiss marijuana samples from different regions. Data treatment by principal component analysis and hierarchical cluster analysis allowed a discrimination of the different batches.