Variation in chemical profiles within large seizures of cocaine bricks

Cocaine is usually trafficked from South America throughout the world in packages of approximately one kilogram shaped as bricks and imprinted with a logo. Seizures consisting of multiple cocaine bricks gives the opportunity to examine the variation in the chemical profile within cocaine bricks assumed to originate from the same manufacturer and maybe even the same production batch. This knowledge may be important to the forensic investigator when chemical profiles from cocaine samples of unknown origin are compared. In the present study, the alkaloid and residual solvent profiles from three large cocaine seizures each containing identical cocaine bricks was examined. The three cases consisted of 36, 84 and 100 cocaine bricks, respectively. Each cocaine brick was profiled according to its cocaine alkaloid and residual solvent content using gas chromatography-mass spectrometry (GC-MS) and headspace GC-MS. The study showed that each of the three identical looking seizures consisted of up to four groups of cocaine bricks displaying the same cocaine alkaloid and residual solvent profile. The size of the groups varied from 2.4 to 63.3kg cocaine. The study also showed that the residual solvent profile within each of the three large seizures exhibited very little variation whereas the alkaloid profile varied considerably more. This finding suggest that the same organic solvent is used for the production of several batches of cocaine HCl. Therefore, the residual solvent profile may be a tool to link different production batches from the same manufacturer even though the alkaloid profile are different.