A database for comparison analysis of illicit cocaine samples

A rapid method for comparison analysis of illicit cocaine samples was developed and used to compile a cocaine database. The raw data was obtained by capillary gas chromatography using a nitrogen-phosphorus detector. The area ratios of four alkaloids (tropacocaine, norcocaine, cis-cinnamoylcocaine, and trans-cinnamoylcocaine) to cocaine were calculated for each sample. Multivariate statistical techniques were used to show that the four alkaloid ratios were sufficient to distinguish cocaine samples from unrelated sources. A threshold Euclidian distance for identifying matching cocaine samples was calculated and a statistical binning system for estimating the frequency of occurrence of these cocaine sample compositions was proposed. Such a frequency estimate would be useful in determining whether particular cocaine sample compositions are common or rare and influence the weight of conclusions regarding their commonality of origin.