Method development for the analysis of synthesis markers from clandestine amphetamine production via the Leuckart route in wastewater using polydimethylsiloxane rods for passive sampling in combination with GC-MS techniques

Clandestine amphetamine synthesis via the Leuckart route generates large amounts of toxic aqueous production waste, often disposed into the sewer system by criminal producers. The detection of synthesis markers from production waste by wastewater analysis can indicate waste disposal and contribute to the localization of a clandestine laboratory responsible for the discharge. Traditional approaches usually require laborious sample acquisition and preparation. In this study, polydimethylsiloxane (PDMS) rods were investigated for their use as passive samplers, which enable isolation and enrichment from complex aqueous matrices in a single step, followed by direct analysis by thermal desorption gas chromatography – mass spectrometry (TD-GC-MS) techniques. In this work, the suitability of PDMS rods for extraction of amphetamine synthesis markers from the Leuckart route in wastewater influent is systematically tested and evaluated. The extraction procedure was optimized for five target compounds, yielding extraction efficiencies from 9 % to 82 %. Furthermore, two TD-GC-MS methods using a bench-top and a portable instrument for potential rapid on-site analysis were validated. The overall methodology proved to be repeatable with RSDs from 4.4 % to 20.1 % (bench-top system) and from 6.6 % to 14.8 % (portable system). Lowest LOD values for a single compound (4-methyl-5-phenylpyrimidine) were 0.9 and 1.5 ng in 10 mL samples for the bench-top and portable system, respectively. Analysis of wastewater samples spiked with real production waste highlighted the wide range of compounds that can be extracted using PDMS rods. Furthermore, the application of PDMS rods in forensic case work is described.