Statistical comparison of mass spectra of salvinorins in Salvia divinorum and related Salvia species

In many forensic science disciplines, mass spectrometry is used for the analysis and comparison of case samples to reference materials. To increase confidence in identifications made from such comparisons, our laboratory previously developed a method for the statistical comparison of unabbreviated mass spectra. The method uses the unequal variance t-test to statistically compare ion abundances across the mass scan range. In the current work, the method was applied for the comparison of mass spectra of salvinorin A, the hallucinogenic compound in the plant Salvia divinorum. S. divinorum samples collected from eight locations in the United States and Canada were extracted and analyzed by gas chromatography-mass spectrometry (GC–MS). Mass spectra of salvinorin A from three replicate extracts of S. divinorum were statistically associated with those of an authentic salvinorin A reference material at various concentrations at the 99.9% confidence level. Salvinorin A was distinguished from spectra of salvinorins B, C, and D, also at the 99.9% confidence level. For S. divinorum samples from different locations, statistical association of salvinorin A spectra was possible at the 99.9 to 98.0% confidence levels. Finally, 441 different Salvia species and varieties were screened for salvinorin A and mass spectra of compounds with similar retention times were statistically discriminated from salvinorin A at the 99.9% confidence level. Overall, spectra of salvinorin A were associated to each other and discriminated from other compounds in plant materials obtained from different locations, extracted using different procedures, and analyzed using different GC–MS instruments and methods over a three-year period.