Polymer-coated filter paper as a novel vapor sampling method for fentanyl

The current study introduces a novel polymer-coated filter paper sampler for passive vapor sampling and preconcentration of N-phenylpropanamide (NPPA), a target vapor surrogate for fentanyl, enabling presumptive identification of fentanyl. Building on prior work by, which identified ethylene glycol methyl ether acrylate (EGMEA) as a selective polymer for NPPA pre-concentrating, the present study evaluates EGMEA-coated filter paper as a practical and robust vapor sampler for fentanyl. Laboratory experiments demonstrated that EGMEA-coated filter paper effectively adsorbed NPPA, yielding 3.6 × 10³ ng per quarter section of a 45 mm filter paper after a 48 h exposure to from 5 mg NPPA. Additionally, detectable levels of NPPA (39 ng per quarter) were observed following one week of passive sampling from 100 mg of reference-grade fentanyl. The validated sampler was then deployed in a drug laboratory survey across three forensic laboratories using standardized sampling kits. NPPA was detected from the seized fentanyl samples of diverse composition, with variable recoveries reflecting possible differences in formulation, dilution, and co-constituents. The EGMEA-coated filter paper platform offers a simple, low-cost, robust, alternative to conventional Solid Phase Microextraction (SPME) fibers and sorbent tubes. Coupled with Thermal Desorption - Gas Chromatography/Mass Spectrometry (TD-GC/MS) for confirmation of NPPA, this work establishes EGMEA-coated filter paper as an effective field sampler for presumptive fentanyl identification, supporting field-based measurements in forensic research applications.