Rapid on-site screening could help protect bar staff from hidden drug exposure

The study, published in the Journal of Mass Spectrometry, tested the method in a working UK pub and found traces of cocaine and ketamine on surfaces across bathrooms, tables and bar areas. 

The technique, atmospheric solids analysis probe mass spectrometry (ASAP-MS), skips the chromatographic separation step that traditional methods require –  where a sample is first sorted into its individual ingredients before being identified in a lab. A sample is introduced via a glass capillary rod into a heated source, vaporised by nitrogen gas, and ionised without separation.  

Analysis takes under two minutes, and that speed and simplicity could make rapid, on-site drug screening practical for venues, crime scenes or other locations where quick turnaround matters. 

Over three weeks, the Surrey team collected 420 surface swabs from a single pub in the south of England. They tested three distinct workflows – direct untargeted analysis of swabs with no sample preparation, untargeted analysis of solvent-extracted samples, and targeted analysis monitoring specific chemical signatures. The targeted method using solvent-extracted samples achieved an overall diagnostic accuracy of 64.29 per cent for cocaine and 83.81 per cent for ketamine, compared against confirmatory laboratory testing. 

The study found cocaine on all sampled bathroom surfaces using all three workflows. Concentrations were highest in bathroom areas, consistent with prior research showing that public bathrooms in venues are frequently used for substance consumption. The method identified very small amounts of cocaine and ketamine using the targeted approach. 

The lowest levels were 20 picograms per microlitre for cocaine and 0.78 nanograms per microlitre for ketamine. Twenty picograms is about a millionth of the weight of a single human hair. Spread through a microlitre, which is a droplet far smaller than a pinhead, it is vastly less than anyone could see or feel. The ketamine figure is about 40 times higher than the cocaine figure, but it is still roughly a billionth of a gram in a droplet too small to see clearly. 

Ketamine proved more challenging to detect than cocaine because it remains trapped in cotton swab fibres and has lower volatility, meaning it vaporises more slowly during analysis. Direct analysis of swabs missed significant amounts of ketamine that were later confirmed by traditional laboratory testing. Solvent extraction recovered those trapped compounds but added preparation time. The researchers identified 15 false positives across the three workflows, some attributed to procaine – a cutting agent occasionally mixed with cocaine – which produces a nearly identical chemical signature to ketamine. 

The study is among the first to assess surface contamination in an operational venue and to test whether portable mass spectrometry could serve as a practical detection tool for public health or occupational safety applications.