Detection of trace fentanyl in latent and developed fingermarks using atmospheric solids analysis probe (ASAP) mass spectrometry.

Latent fingermarks are vital evidence for identifying criminals using the unique ridge pattern and mass spectrometry can identify relevant chemical information from contact or exposure. Ambient ionisation mass spectrometry has many advantages that make it suitable for forensic workflows such as being user-friendly, low cost and having a small footprint. This work is concerned with detection of fentanyl, a highly potent synthetic opioid that has recently caused a significant number of overdoses, in latent fingermarks. A protocol was developed to produce fentanyl spiked fingermarks that were subsequently sampled using a liquid extraction method and analysed on a Waters RADIAN ASAP-MS. Initial results showed most fentanyl was recovered from a spiked fingermark and the detection limit was determined to be less than a nanogram. Latent fingermarks are typically visualised using an appropriate development technique before additional chemical information is recovered. Therefore, further studies assessed the ability to detect fentanyl in spiked fingermarks following three development techniques: cyanoacrylate (CyanoBloom), cyanoacrylate with UV dye (PolyCyano UV), and cyanoacrylate followed by staining with Basic Yellow 40 (BY40). Fentanyl was still detected after all three development methods tested, with detection limits reaching 10 ng or less present on the surface. This highlights that trace chemicals can be retained in fingermarks and recovered after development, the success of a simple liquid extraction method to recover analytes of interest and demonstrates how ambient ionisation methods are capable of reliably detecting analytes such as synthetic opioids from a complex matrix. This further exemplifies ambient ionisation as a solution to forensic testing backlogs by providing valuable information to criminal investigations quickly and effectively.