High-throughput screening of PAHs and polar trace contaminants in water matrices by direct solid-phase microextraction coupled to a dielectric barrier discharge ionization source

Abstract

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.

Hunting Molecules in Complex Matrices with SPME Arrows: A Review

“…The future of the SPME Arrow is promising, and among the multiple research and application avenues, this new geometry of SPME may grow rapidly. The following three areas are anticipated to expand: the development of new extraction phases [26,55,56], the Arrow's direct interface with MS instrumentation [59], and the Arrow's evolution towards smarter devices.…”

“…As recently reviewed by Gomez-Rios and Mirabelli [4], the direct interface of SPME devices to MS has been increasing in the last five years, and SPME Arrows have not been an exception. For instance, research from the Zenobi's group demonstrated the applicability of an automated SPME Arrow workflow, hyphened with a dielectric barrier desorption ionization (DBDI) coupled to an LTQ Orbitrap, to analyze common organic contaminants in treated wastewater (see Figure 8) [59]. Limits of detection as low as 3 ng/L were attained with a total analysis time per sample of less than 10 min (see Figure S3).…”

“…Schematic drawing (a) and image (b) of the sample introduction system (with and without dopant), source, and dielectric barrier desorption ionization (DBDI) interface with the mass spectrometer.Figure reprintedwith permission of Elsevier from Reference[59], 2020.…”

Rapid screening and quantitation of PAHs in water and complex sample matrices by solid‐phase microextraction coupled to capillary atmospheric pressure photoionization‐mass spectrometry

“…However, the analytical sensitivity towards the nonpolar compound is often too low to allow detection and quantification in ultratraces. Several attempts have been made in this direction to improve the ionization efficiency of PAHs, with, for example, approaches based on a combination of DART and dopant‐assisted APPI, 10 dopant‐assisted DART, 11 and dopant‐assisted DBDI 12,13 …”

Solid‐phase microextraction Arrow for the volatile organic compounds in soy sauce

“…However, very little information on volatile analysis by using SPME Arrow is currently available because this technique has emerged very recently. Most published researches have focused on polycyclic aromatic compounds in water and volatile amines in wastewater and atmosphere . Moreover, to the best of our knowledge, studies on VOC analysis by SPME Arrow in food matrices have not been reported yet.…”