Development of a Drone-Based Thin-Film Solid-Phase Microextraction Water Sampler to Facilitate On-Site Screening of Environmental Pollutants

To simplify on-site water sampling and screening, particularly in hard-to-reach or dangerous sites, a drone equipped with a hydrophilic-lipophilic balance (HLB), thin-film solid-phase microextraction (TF-SPME) sampler was developed. The drone-based sampler was shown to protect the sorbent phase from external contamination while preventing any detectable loss of components of a spiked modified McReynolds mixture on the membrane in the sampler for at least 10 min. HLB/poly(dimethylsiloxane) (PDMS) membranes deployed in flight on the drone sampler were demonstrated to extract disinfection by-products, including trichloromethane, dichloroacetonitrile, 1,1,1-trichloro-2-propanone, 2,2,2-trichloroethanol, benzonitrile, and benzyl nitrile, from hot tub water. When analyzed on-site, in duplicate, using hand-portable instrumentation, reasonably repeatable results were achieved (%relative standard deviations (RSD's) 5-16%). Finally, drone TF-SPME sampling of an anthropogenically impacted watercourse indicated that impact from the suspected nearby landfill site was minimal, instead suggesting that internal combustion by-products from vehicles on the nearby Highway 401 played a much larger role in contaminating the watercourse. This conclusion was supported by the confirmed presence of BTEX, styrene, isopropylbenzene, propylbenzene, and 1,3,5-trimethylbenzene. In addition to immediately identifying these compounds on-site using portable gas chromatography-mass spectrometry (GC-MS), samples were taken back to the laboratory for benchtop analysis, further supporting this conclusion.