RESUMEN
Most illicit drug casework samples at the Israel Police National Drug Laboratory are found to be mixtures of substances. Some are a mixture of an illicit drug with fillers, and others may contain more than one illicit drug. This study was triggered by a routine gas chromatography-mass spectrometry (GC-MS) analysis of an unusual casework sample. The sample chromatogram showed a mixture of two illicit drugs, 4-acetoxy-DMT and psilocin. Considering the two substances' similar skeletal structure, the authors wondered whether the sample was indeed a mixture of the two substances, or whether perhaps 4-acetoxy-DMT was hydrolyzed to psilocin during the analysis. This study hypothesized that indeed the base used in the pre-injection sample preparation hydrolyzed the ester group on the 4-acetoxy-DMT yielding a hydroxide group. This was tested using several concentrations of ammonium hydroxide and two additional bases - pyridine (a weak base) and sodium hydroxide (a strong base). Results showed that media with a higher pH (induced by the stronger base) yielded a higher psilocin to 4-acetoxy-DMT ratio which is compatible with degradation of 4-acetoxy-DMT. This study also explored the possibility that psilocin was a byproduct of thermal decomposition of 4-acetoxy-DMT and found it thermally stable in the temperature of the GC injection port (200°C). The 4-acetoxy-DMT case demonstrates how pre-injection laboratory procedures can inadvertently modify casework samples. Caution is clearly advisable in selecting reagents and processes in general, and specifically in the case of GC-MS pre-injection procedures conducted to analyze substances like the ones in the present study.