Determination of dimethoxyphenethylamine derivatives in urine by deuterium labeled internal standards

The use of gas chromatography-mass spectrometry (GC-MS) in fo- rensic analysis is increasing. To exploit fully the capabilities of MS, labeled standards, that can be used to improve the performance of the quantitative ana- lysis, and to increase accuracy and precision, are required. A series of deute- rated internal standards, corresponding to the 2C-series of phenethylamine derivatives, including 4-bromo-2,5-dimethoxyphenethylamine-d6 (2C-B), 4-chlo- ro-2,5-dimethoxyphenethylamine-d6 (2C-C), 4-iodo-2,5-dimethoxy-phenethyl- amine-d6 (2C-I), 4-ethylthio-2,5-dimethoxy-phenethylamine-d6 (2C-T-2) and 2,5-dimethoxy-4-n-propylthiophenethylamine-d6 (2C-T-7), were synthesized. These deuterated compounds were used to analyze for the corresponding un- labeled compounds in urine. The analysis was performed using GC-MS, with the selected ion monitoring (SIM) technique, whereby good results were achieved.