Ambient mass spectrometry enables fast and direct analysis, requiring minimal or no sample preparation; these attributes have established it as the preferred technique for applications in numerous fields (e.g., biomedical, forensic, and environmental). Here we coupled an active capillary plasma ionization source based on a dielectric barrier discharge directly to solid-phase microextraction, achieving a quick (<10 min per sample), green (virtually no samples preparation and thus no solvents involved), sensitive (LODs up to 3 pg mL), robust (RSD of <20%), and quantitative (LDR ≥ 2 orders of magnitude) screening method. This study, moreover, shows that intrinsically poorer ionization efficiencies for low-polarity compounds (such as polycyclic aromatic hydrocarbons, PAHs), which precluded their ultra-trace detection, can be partially overcome by adding dopants and lowering the LODs into the pg mL range. Results also show that the presence of these dopants greatly affects the ionization mechanism, resulting in the preferential formation of radical cations versus protonated PAHs. As a proof of concept, this method was applied to the detection of organic microcontaminants in different water matrices (such as tap, ground, and treated wastewater). Common contaminants (e.g., DEET, benzotriazole, β-estradiol) were tentatively detected and, if above the LOQ, quantified (i.e., DEET at 30 pg mL). These promising results evidence that this approach is interesting for quick (field) screening methods, and the newly increased efficiency for a larger polarity range additionally expands the range of possible applications.
