E-cigarette drug detection device. Device design is described in the main text (Figure ). The e-cigarette adapter and vacuum chamber assembly are constructed from threaded lens tubes (Thor Labs). Detection apparatus including: 265nm LED (ThorLabs), photodiodes (Scitech instruments Ltd.) and sapphire window (ThorLabs) are offthe-shelf components. The device is controlled by Arduino nano RP2040 running a custom CircuitPython script. The Arduino, LED, photodiodes, vacuum pump and the LED indicator strip (AdaFruit) are driven by a custom-made printed circuit board. The custom-made housing was 3Dprinted in ABS plastic using an Ultimaker S3. The device uses Whatman 42, 2.5 μM pore size ashless filters for e-liquid drug detection.