Paper spray mass spectrometry for the direct, semi-quantitative measurement of fentanyl and norfentanyl in complex matrices

Fentanyl is a potent, synthetic opioid at the centre of an international health crisis that has seen thousands of fatal overdoses. Most analytical methods focus on the detection of fentanyl in blood and/or urine (i.e., post-drug use). Harm reduction (including pre-screening before drug use) may be an effective strategy against fentanyl overdoses. Paper spray-mass spectrometry (PS-MS) is an inexpensive, direct sampling strategy where a small volume of sample (