An external reference 1H qNMR method (PULCON) for characterization of high purity cocaine seizures

Abstract

An external reference ¹H qNMR method is developed and validated for the determination of three major alkaloids – cocaine, cis-cinnamoylcocaine and trans-cinnamoylcocaine – in high purity cocaine seizures. The method was applied to a set of 26 cocaine samples seized by the Brazilian Federal Police with cocaine contents ranging from approximately 63% to 94% (w/w) and cinnamoylcocaines ranging from 0.33% to 5.82% (w/w). The method enables the determination of these main alkaloids in 15 minutes of analysis with excellent accuracy (relative error <5% compared to the reference material certificate) and precision (RSD <3%). Some figures of merit are presented, including accuracy, recovery, repeatability, intermediate precision, stability, robustness, uncertainty, and limit of detection. The results show excellent correlation compared to the reference GC-FID methodology. It also permits the determination of the oxidation degree of samples. The method can be readily adapted to other analytes.