Analysis of cocaine samples from amnesty bins located at a major UK summer music festival over a 10-year period using both low-field benchtop NMR (60 MHz) and medium-field NMR (400 MHz) for comparison.

Cocaine is the second most popular traditional illicit drug in the European Union, after cannabis, and its high potential for addiction makes it a significant public health concern. Therefore, monitoring trends in the content and purity of street samples can provide valuable information to support harm reduction strategies. This study analysed a selection of 160 street cocaine samples collected at a large British summer festival between 2014 and 2024. A comparison between a low-cost, transportable 60 MHz benchtop nuclear magnetic resonance (NMR) instrument and a more expensive, larger laboratory-based 400 MHz NMR device was used to assess variations in composition and purity levels. Despite a lower signal-to-noise ratio and signal overlap causing some differences in values, the benchtop NMR produced almost identical results to those of the 400 MHz system. Until 2014, cocaine samples were highly adulterated; their purity increased sharply from 2015 onwards, with levels ranging from 80% to 98%, before showing a downward trend in 2024. The most commonly detected cutting agents were benzocaine, levamisole, caffeine, phenacetin, and lactose. Overall, this work demonstrates that low-field NMR can be effectively used to quantify cocaine in street samples. This could be especially beneficial on-site for guiding and enhancing harm reduction services and law enforcement.