Advantages and limitations of a programmable sampling unit combined with PDMS passive samplers and TD-GC-MS for...

Clandestine production of synthetic drugs like amphetamine generates tremendous amounts of chemical waste which may partly be disposed into the sewage system by the producers. Specific synthesis-related marker compounds present in the production waste thus enter wastewater after discharges. Hence, wastewater monitoring could be an additional tool for law enforcement agencies to localize clandestine laboratories that dispose production waste into the sewage system. For such a scenario, a programmable sampling unit may be useful, which can be installed in manholes to access the sewage line and which could provide time-resolved composite samples. In contrast to common sampling at wastewater treatment plants, this approach provides a higher spatial resolution. In this study, small volumes of amphetamine production waste were discharged into real sewage environments in combination with a progammable sampling unit for sample collection. Composite (time-proportional) and event-triggered sampling protocols were tested for the detection and time correlation of waste discharges. Analytes from these wastewater samples were extracted with polydimethylsiloxane rods in the laboratory which proved to be easy to use and effective passive sampling devices to extract relevant amphetamine synthesis markers from wastewater matrix. The controlled discharge experiments in the sewer system showed that clandestine discharges can be tracked and traced with composite (time-proportional) sampling. Furthermore, event-triggered sampling was enabled via continuous pH measurements due to the often extreme pH values of amphetamine production waste. In addition, the detection of synthesis markers from production waste discharges by direct wastewater sampling in the sewage line with polydimethylsiloxane rods was tested.