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.