ASAP-MS Screening of Drug Residues on Pub Surfaces

Overview

Researchers collected 420 swabs over three weeks from an anonymous pub in southern England. LC-MS detected cocaine and ketamine, with 250 cocaine and 70 ketamine detections; 64 swabs contained both substances. Targeted ASAP-MS after methanol extraction produced 118 positive findings but had high false-negative rates compared with LC-MS.

Background

Researchers assessed atmospheric pressure solids analysis probe mass spectrometry (ASAP-MS) as a rapid screening approach for drug residues on surfaces and compared several ASAP-MS workflows with laboratory-based liquid chromatography–mass spectrometry (LC-MS). They collected 420 swabs over three weeks from an anonymous pub in southern England, sampling areas in the men’s and women’s bathrooms, on tables, and along a copper bar. The team tested for cocaine, ketamine, amphetamine, diazepam, and tetrahydrocannabinol; LC-MS detected only cocaine and ketamine. A positive surface-residue result shows that a substance was present on the sampled surface but does not establish whether it was consumed at the venue, when or how it was deposited, or who deposited it.

Data Highlights

Key Findings

• LC-MS detected cocaine and ketamine, but none of the other three substances tested.
• Cocaine was found on more than half of the swabs; the men’s bathroom had the most cocaine detections, followed by the women’s bathroom.
• Bathrooms had the highest number of ketamine detections; residues were less frequent on tables and the copper bar.
• Direct, untargeted ASAP-MS mainly detected samples with relatively high cocaine levels and missed many lower-level residues identified by LC-MS.
• Methanol extraction combined with targeted ASAP-MS increased sensitivity, but the method still missed 59.51% of cocaine-positive and 88.57% of ketamine-positive samples identified by LC-MS.
• Some apparent ketamine signals were associated with procaine, illustrating the challenge of distinguishing compounds with similar mass signals using a single-quadrupole instrument without chromatographic separation.

Clinical Implications

The study authors state that ASAP-MS would be more appropriate for initial screening than for confirming the presence or absence of a drug, given the high false-negative rates. They report that further work is needed to optimize temperature control, extraction volumes, matrix-matched controls, and data-analysis software before routine on-site screening can be considered.

Conclusion

ASAP-MS provided rapid screening but did not match LC-MS for detecting the residues identified in this pub survey. Extraction and targeted acquisition improved detection, while substantial false-negative rates and potential compound interference remained.

Related Resources & Content

1. Assessing the use of ASAP‐MS for Screening a UK Pub for Illicit Drug Substances, 2026
2. Association for Diagnostics & Laboratory Medicine, ADLM Guidance Document on Laboratory Testing for Drugs of Misuse to Support the Emergency Department, 2026
3. the medicine maker — What’s on the Box?
4. the medicine maker — Post-FMD, Post-Problems?
5. the medicine maker — Track & Chase
6. Food Safety and Risk — Veterinary drug residues in animal-derived foods: linking pharmacokinetics, processing transformations, and detection to global food safety governance
7. Assessing the use of ASAP‐MS for Screening a UK Pub for Illicit Drug Substances
8. ADLM Guidance Document on Laboratory Testing for Drugs of Misuse to Support the Emergency Department
9. Forensic Scientists' Exposure to Illicit Drugs | NIOSH Science Bulletin | CDC