Chemical signature of ecstasy volatiles by comprehensive two-dimensional gas chromatography

A method for ecstasy volatiles 'signature' analysis based on two-dimensional gas chromatography separation and time-of-flight mass spectrometry detection (GC×GC-TOFMS) is presented. Organic impurity volatiles were extracted by head space solid phase microextraction (HS-SPME). The final column phase choice of the four different column combinations tested was a low-polarity 5% phenyl polysilphenylene-siloxane coupled with a polyethylene glycol phase, which best displayed the complex impurity profile. Second dimension ((2)D) retention time reproducibility was found to be about 1% RSD, and area reproducibility of SPME sampling was just over 5% RSD for compounds with S/N ratio of about 100. High similarity of TOFMS spectra of impurities was obtained against commercial MS libraries. 16 components from the two-dimensional profiles were selected for comparison of the 24 ecstasy tablets, most of which proved to be benzodioxole derived compounds. All tablets were correctly classified in eight groups according to their post-tabletting characteristics, when appropriate data pre-treatment was applied. Principal component analysis revealed clustering of samples according to the country of origin. Samples from Macedonia were elevated in N-formyl-MDMA and N-acetyl-MDMA while samples from Australia were elevated in 3,4-methylenedioxypropane and 3,4-methylenedioxyacetophenone. Furthermore, three components were found to be unique for one of the source countries. The additional separation of components on the (2)D column, increased response due to modulation, high acquisition rate with full mass spectra using TOFMS detection, and MS deconvolution extend the possibility of detecting additional markers and route-specific components, especially of low abundant, polar components.