Towards on-site analysis of complex matrices by solid-phase microextraction-transmission mode coupled to a portable mass spectrometer via direct analysis in real time.

On-site screening for target analytes in complex matrices, such as biofluids and food specimens, not only requires reliable and portable analytical instrumentation, but also solvent-free and easy-to-use sampling/sample preparation approaches that allow analytes of interest to be isolated from such matrices. The integration of sampling devices with field deployable instruments should be as efficient as possible, and should aim to provide rapid, precise, and accurate results that enable quick on-site decision. In this study, we evaluated solid-phase microextraction-transmission (SPME-TM) coupled to a portable single quadrupole MS system, via direct analysis in real time (DART), as an effective tool for the rapid screening of target analytes in biological and food matrices. Limits of quantitation (LOQ) in the low parts-per-billion levels (≤50 ng mL-1) were attained for most of the investigated analytes with total analysis times under 2 min per sample. Furthermore, we explored the suitability of this technology for on-site rapid molecular profiling of complex matrices. As a proof-of-concept, we demonstrate the rapid identification of milk samples from assorted animal and vegetal sources.