Single-use porous polymer thin-film device: A reliable sampler for analysis of drugs in small volumes of biofluids

Abstract

The response to the demand for biomedical testing on small volumes of biofluids has led to a range of new microsampling devices and related techniques. Simple cost-effective sampling devices are available, but most do not incorporate sample clean-up and necessitate extensive sample processing by the analyst. To address both cleanup and analyte stability, a porous polymeric thin film made of methacrylic acid (MAA) and ethylene glycol dimethacrylate (EGDMA) coated (5 × 18 mm2) on a stainless steel substrate was used for the extraction of seven tricyclic antidepressants (TCAs) from plasma spots, with analysis by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Essential factors such as sample volume, extraction time, matrix effects, and the desorption process were investigated. The optimized method is comprised of a quick 3-min extraction from 10 μL of plasma, a wash (10 s in 1 mL of 1% aqueous triethylamine (TEA) to remove plasma matrix interferences, and 2-min desorption (200 μL of ACN with 0.1% formic acid (FA)). For the purpose of sample archiving, thin film devices containing extracted TCAs were stored for 30 days at room temperature and showed a consistent analyte recovery. Inter-device reproducibility was evaluated without internal standard (%RSD 8.2–19.3%), and using two methods of introducing a single deuterated internal standard (imipramine-D3) either prior to (%RSDs 5.6–13.9%) or after (%RSDs 4.9–10.2%) sample loading to the device. Although the intention of this study was to introduce a single use device for rapid and easy analysis, reusability showed the feasibility of 15 consecutive extractions using same device without any performance loss. The optimized method revealed excellent linearity (R2 > 0.99) in the range of 1–1000 ng mL−1, with good intra- and inter-day accuracy (81.4–118%) and precision (≤12%) in human plasma.