Emanuela Gionfriddo

Neutral volatile and semi-volatile per- and polyfluoroalkyl substances (PFAS) remain an under-quantified source of human and environmental PFAS exposure, largely due to their trace-level occurrence and the complexity of matrices. These analytical challenges underscore the need for selective extraction approaches capable of minimizing matrix interferences. In this work, a new generation of solid phase microextraction (SPME) devices, incorporating a polymeric ionic liquid (PIL) sorbent featuring linear and branched perfluoroalkyl moieties was developed, and their capability for the selective extraction and preconcentration of neutral volatile PFAS was systematically evaluated. The inclusion of fluorinated structural elements within the sorbents increased their affinity toward fluorinated analytes, consistent with enhanced fluorophilic interactions. In addition, the sorption mechanism of the developed fluorinated PIL-based SPME fibers was investigated. While most PIL fibers exhibited absorption-type partitioning, a PIL fiber featuring a fluorinated monomer and a cross-linker displayed adsorption behavior, as evidenced by the concentration-dependent competitive adsorption of lower-affinity analytes by higher-affinity species. Energy-dispersive X-ray spectroscopy (EDX) maps of the fluorinated PIL fiber revealed a heterogeneous fluorine distribution, indicating tightly clustered perfluorinated domains. The fluorinated sorbents were compared to a commercial divinylbenzene (DVB)/carbon-wide range (C-WR)/PDMS SPME fiber using non-targeted extraction of volatile organic compounds (VOCs) from the headspace (HS) of paint samples to assess relative selectivity. The PIL fibers exhibited markedly enhanced selectivity toward fluorinated compounds relative to non-fluorinated VOCs, achieving PFAS-positive hit rates of 4-17%, compared to only 1% observed with a commercial, non-fluorinated sorbent.

Cannabis sp. has been widely used for both medicinal and recreational purposes globally. Analyzing cannabinoids and their metabolites in human plasma samples is crucial for managing acute intoxications and for therapeutic monitoring in patients. This study describes the optimization and validation of an innovative, sensitive, simple, and environmentally friendly biocompatible solid-phase microextraction (bio-SPME) method using a hydrophilic-lipophilic balance (HLB)/polyacrylonitrile (PAN)-thin film for the quantification of cannabinoids (cannabidiol, tetrahydrocannabinol, and cannabinol) and their main metabolites (11-hydroxy-Δ9-tetrahydrocannabinol and 11-nor-9-carboxy-Δ9-tetrahydrocannabinol acid) in human plasma samples. Extraction efficiency was compared between two geometry SPME devices (e.g., thin film and fiber geometry), showing that the use of the thin film microextraction (TFME) device improved extraction performance. Matrix modification was optimized using a central composite design to determine the optimal combination of sample dilution, organic modifier addition, and salt usage. The most effective matrix modification was achieved with 380 µL of phosphate-buffered saline solution containing 0.015 mol L⁻¹ sodium chloride and 57% acetonitrile added to 200 µL of human plasma. The extraction equilibrium time was established as 30 min, and the desorption step required only 20 min in 200 µL of desorption solvent. The method demonstrated linearity, high sensitivity, precision, and good accuracy, with no significant carryover between samples. When compared with recent methods, this approach scored higher in terms of “greenness” according to the AGREEprep metric, making it an environmentally sustainable option. Graphical abstract

Neutral per- and polyfluoroalkyl substances (PFAS) serve as precursors to perfluorinated acids, and their transformation contributes to the ongoing release of legacy PFAS contaminants into the environment. The accurate and efficient extraction of neutral, volatile PFAS remains a critical analytical challenge. In this study, we evaluated the impact of solid phase microextraction (SPME) geometry and agitation methods on extraction performance using SPME-fiber and SPME-arrow devices in headspace (HS) and direct immersion (DI) extraction modes. Agitation of the samples during extraction was conducted with a cycloid-shaped Heatex agitator at 600 rpm and compared to an orbital shaker at 250 rpm. Results demonstrated that SPME-arrow devices offered enhanced sensitivity and broader linear dynamic ranges for fluorotelomer alcohols such as 1H,1H,2H,2H-perfluoro-1-hexanol (4:2 FTOH). In contrast, SPME-fibers showed improved response for hydrophobic, semi-volatile analytes such as N-methylperfluorooctanesulfonamidoethanol (MeFOSE) with lower limits of quantitation (0.005 μg L⁻¹–0.25 μg L⁻¹). The influence of extraction mode on SPME-geometry was systematically investigated with residual plots (DI-HS) reaffirming the propensity for extraction by DI of hydrophobic, semi-volatile analytes and volatile analytes by HS. The Heatex agitator improved extraction efficiency for diffusion-limited compounds by enhancing convective mixing and reducing mass transfer resistance in the boundary layer. Extraction time profiles suggested the occurrence of competitive adsorption at extraction times longer than 35 min. These findings underscore the importance of tailoring SPME parameters – agitation type, extraction mode, time, and sorbent geometry – when developing sample preparation workflows for analysis of neutral volatile PFAS.

Research efforts have primarily focused on identifying per- and polyfluoroalkyl substances (PFAS) in common environmental media like water, air, soil, and biological samples. However, there is limited research on PFAS detection in complex samples such as personal care products, including cosmetics. PFAS are used in cosmetics for emulsification, surfactant action, and stabilization, and have been detected in products such as foundation, powders, and nail polish. The complexity of cosmetic formulations, with various additives, makes the analysis of these samples extremely challenging. This study aimed to explore and develop convenient extraction methods to accurately quantify eight anionic PFAS in mascara products. Solid-phase microextraction (SPME) and automated micro solid-phase extraction (µSPE) were evaluated, and quantification was performed using liquid chromatography-tandem mass spectrometry (LC–MS/MS). Six mascara products, including waterproof and non-waterproof types, were analyzed, optimizing methanol–water mixtures as dispersive media to maximize PFAS recovery. Elution solution composition, volume, and dispensing speed were optimized for the µSPE method to ensure quantitative elution of the PFAS from the extraction phase. For the SPME method, the extraction time was optimized to account for the varying diffusion behavior of PFAS in the mixed-phase medium. Both extraction methods were evaluated in terms of greenness and practicality, with SPME achieving the best overall scores. Method validation demonstrated good linearity (0.025 to 25 ng/g) for both protocols, with µSPE providing lower limits of quantification (LOQ) for the most hydrophobic PFAS. 6:2 diPAP was quantified in real samples at concentrations ranging from 1.26 to 3.48 ng/g in 4 of the 9 mascaras tested. Graphical Abstract