Alicyclobacillus spp. in fruit-based products: Isolation, identification, quantitative assessment (SPME/GC-MS) of spoilage compounds and spore's resistance to thermal shocks.

Alicyclobacillus spp. is the cause of great concern for the food industry due to their spores' resistance (thermal and chemical) and the spoilage potential of some species. Despite this, not all Alicyclobacillus strains can spoil fruit juices. Thus, this study aimed to identify Alicyclobacillus spp. strains isolated from fruit-based products produced in Argentina, Brazil, and Italy by DNA sequencing. All Alicyclobacillus isolates were tested for guaiacol production by the peroxidase method. Positive strains for guaiacol production were individually inoculated at concentration of 103 CFU/mL in 10 mL of orange (pH 3.90) and apple (pH 3.50) juices adjusted to 11°Brix, following incubation at 45 °C for at least 5 days to induce the production of the following spoilage compounds: Guaiacol, 2,6-dichlorophenol (2,6-DCP) and 2,6-dibromophenol (2,6-DBP). The techniques of micro-solid phase extraction by headspace (HS-SPME) and gas-chromatography with mass spectrometry (GC-MS) were used to identify and quantify the spoilage compounds. All GC-MS data was analyzed by principal component analysis (PCA). The effects of different thermal shock conditions on the recovery of Alicyclobacillus spores inoculated in orange and apple juice (11°Brix) were also tested. A total of 484 strains were isolated from 48 brands, and the species A. acidocaldarius and A. acidoterrestris were the most found among all samples analyzed. In some samples from Argentina, the species A. vulcanalis and A. mali were also identified. The incidence of these two main species of Alicyclobacillus in this study was mainly in products from pear (n = 108; 22.3 %), peach (n = 99; 20.5 %), apple (n = 86; 17.8 %), and tomato (n = 63; 13 %). The results indicated that from the total isolates from Argentina (n = 414), Brazil (n = 54) and Italy (n = 16) were able to produce guaiacol: 107 (25.8 %), 33 (61.1 %) and 13 (81.2 %) isolates from each country, respectively. The PCA score plot indicated that the Argentina and Brazil isolates correlate with higher production of guaiacol and 2,6-DCP/2,6-DBP, respectively. Heatmaps of cell survival after heat shock demonstrated that strains with different levels of guaiacol production present different resistances according to spoilage ability. None of the Alicyclobacillus isolates survived heat shocks at 120 °C for 3 min. This work provides insights into the incidence, spoilage potential, and thermal shock resistance of Alicyclobacillus strains isolated from fruit-based products.

Spirulina-based carbon materials as adsorbents for drinking water taste and odor control: Removal efficiency and assessment of cyto-genotoxic effects.

The sensory quality of drinking water, and particularly its taste and odor (T&O) is a key determinant of consumer acceptability, as consumers evaluate water by their senses. Some of the conventional treatment processes to control compounds which impart unpleasant T&O have limitations because of their low efficiency and/or high costs. Therefore, there is a great need to develop an effective process for removing T&O compounds without secondary concerns. The primary objective of this study was to assess for the first time the effectiveness of spirulina-based carbon materials in removing geosmin (GSM) and 2-methylisoborneol (2-MIB) from water, two commonly occurring natural T&O compounds. The efficiency of the materials to remove environmentally relevant concentrations of GSM and 2-MIB (ng L-1) from ultrapure and raw water was investigated using a sensitive headspace solid-phase microextraction coupled with gas chromatography mass spectrometry (HS-SPME-GC/MS) method. Moreover, the genotoxic and cytotoxic effects of the spirulina-based materials were assessed for the first time to evaluate their safety and their potential in the treatment of water for human consumption. Based on the results, spirulina-based materials were found to be promising for drinking water treatment applications, as they did not exert geno-cytotoxic effects on human cells, while presenting high efficiency in removing GSM and 2-MIB from water.

Assessment of volatile emissions by aging books.

Indoor air quality (IAQ) has attracted a lot of attention due to its complexity and direct effect on human health. Indoor settings in libraries entail various volatile organic compounds (VOCs) linked to the aging and degradation of print material. The effect of the storage environment on paper life expectancy was investigated by targeting the VOC emissions of old and new books using headspace solid phase micro extraction-gas chromatography/mass spectrometry (HS-SPME-GC/MS) analysis. "Sniffing" of book degradation markers showed both ubiquitously and infrequently occurring VOCs. Old book "degradomics" revealed mostly alcohols (57%) and ethers (12%), whereas new books resulted mainly to ketones (40%) and aldehydes (21%). Chemometric processing of the results with principal component analysis (PCA) corroborated our initial observations and was able to discriminate the books by age into three groups: very old books (from the 1600 s to mid-1700), old books (from the 1800s to the early 1900s), and modern books (from the mid-twentieth century onwards) based on their gaseous markers. The measured mean concentrations of selected VOCs (acetic acid, furfural, benzene, and toluene) were below the respective guidelines set for similar places (i.e. museums). The applied non-invasive, green analytical methodology (HS-SPME-GC/MS) can assist librarians, stakeholders, and researchers to evaluate the IAQ, as well as the degree of degradation, and take the appropriate measures for book restoration and monitoring protocols.

Comprehensive multicomponent characterization and quality assessment of Xiaoyao Wan by UPLC-Q-Orbitrap-MS, HS-SPME-GC-MS and HS-GC-IMS.

Xiaoyao Wan (XYW) is a prescription medicine of traditional Chinese medicine (TCM) with the effects of "soothing the liver and relieving depression," and "strengthening spleen and nourishing blood". XYW has been widely concerned in the treatment of depression and has become one of the commonly used classic formulas in clinical practice. However, the pharmacodynamic substance basis and the quality control studies of XYW are hitherto quite limited. Here, we aim to fully utilize an advanced ultra - performance liquid chromatography-quadrupole - Orbitrap mass spectrometry (UPLC-Q-Orbitrap-MS), headspace-solid phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) and headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS) technique to deep characterization of the pharmacological substance basis and quantitatively evaluate the quality of XYW. Firstly, 299 compounds were identified or tentatively characterized, including 198 non-volatile organic compounds (n-VOCs) and 101 volatile organic compounds (VOCs). Secondly, principal component analysis (PCA) and hierarchical cluster analysis (HCA) was used to analyze quality differences in XYW at different manufacturers. Thirdly, a parallel reaction monitoring (PRM) method was established and validated to quantify the fourteen major effective substances in different manufacturers of XYW, which were chosen as the benchmarked substances to evaluate the quality of XYW. In conclusion, this study shows that the strategy provides a useful method for quality control of TCM and offers a practical workflow for exploring the quality consistency of TCM.

A low-cost internal standard loader for solid-phase sorbing tools.

Solid-phase sorption is widely used for the analysis of gaseous specimens as it allows at the same time to preconcentrate target analytes and store samples for relatively long periods. The addition of internal standards (ISs) in the analytical workflow can greatly reduce the variability of the analyses and improve the reliability of the protocols. In this work, we describe the development and testing of a portable system for the reliable production of gaseous mixture of8D-Toluene in a 1L Silonite canister as well as its reproducible loading into solid-phase sorbing tools as ISs. The portable system was tested using needle trap microextraction, solid-phase extraction, and thin-film microextraction techniques commonly employed for the analysis of gaseous samples. Even though our specific interest is in breath analysis, the system can also be used for the collection of any kind of gaseous specimen. A microcontroller allows the fine control of the sampling flow by a digital mass flow controller. Flow rate and sample volume could be set either through a rotary encoder mounted onto the control board or through a dedicated android app. The variability of the airflow is in the range 5-200 ml min-1and it is lower than 1%, whereas the variability of the IS (8D-Toluene) concentration dispensed over time by the loader measured by selected-ion flow-tube mass spectrometry (MS) is <3%. This combination resulted in intra- and inter-day precision of the amount loaded in the sorbent tools lower than 15%. No carry-over was detected in the loader after the delivery of the8D-Toluene measured by gas chromatography-MS. The8D-Toluene concentration in the canister was stable for up to three weeks at room temperature.

Assessment of physicochemical properties of sorbent materials in passive and active sampling systems towards gaseous nitrogen-containing compounds.

The adsorption and desorption behavior of volatile nitrogen-containing compounds in vapor phase by solid-phase microextraction Arrow (SPME-Arrow) and in-tube extraction (ITEX) sampling systems, were investigated experimentally using gas chromatography-mass spectrometry. Three different SPME-Arrow coating materials, DVB/PDMS, MCM-41, and MCM-41-TP and two ITEX adsorbents, TENAX-GR and MCM-41-TP were compared to clarify the selectivity of the sorbents towards nitrogen-containing compounds. In addition, saturated vapor pressures for these compounds were estimated, both experimentally and theoretically. In this study, the adsorption of nitrogen-containing compounds on various adsorbents followed the Elovich model well, while a pseudo-first-order kinetics model best described the desorption kinetics. Pore volume and pore sizes of the coating sorbents were essential parameters for the determination of the adsorption performance for the SPME-Arrow sampling system. MCM-41-TP coating with the smallest pore size gave the slowest adsorption rate compared to that of DVB/PDMS and MCM-41 in the SPME-Arrow sampling system. Both adsorbent and adsorbate properties, such as hydrophobicity and basicity, affected the adsorption and desorption kinetics in SPME-Arrow system. The adsorption and desorption rates of studied C6H15N isomers in the MCM-41 and MCM-41-TP sorbent materials of SPME-Arrow system were higher for dipropylamine and triethylamine (branched amines) than for hexylamine (linear chain amines). DVB/PDMS-SPME-Arrow gave fast adsorption rates for the aromatic-ringed pyridine and o-toluidine. All studied nitrogen-containing compounds demonstrated high desorption rates with DVB/PDMS-SPME-Arrow. Chemisorption and physisorption were the sorption mechanisms in MCM-41- and MCM-41-TP- SPME-Arrow, but additional experiments are needed to confirm this. An active sampling technique ITEX gave comparable adsorption and desorption rates on the selective MCM-41-TP and universal TENAX-GR sorbent materials for all the compounds studied. Vapor pressures of nitrogen-containing compounds were experimentally estimated by using retention index approach and these values were compared with the theoretical ones, calculated using the COnductor-like Screening MOdel for Real Solvent (COSMO-RS) model. Both values agreed well with those found in the literature proving that these methods can be successfully used in predicting VOC's vapor pressures, e.g. for the formation of secondary organic aerosols.

Artificial Intelligence decision-making tools based on comprehensive two-dimensional gas chromatography data: the challenge of quantitative volatilomics in food quality assessment.

Effective investigation of food volatilome by comprehensive two-dimensional gas chromatography with parallel detection by mass spectrometry and flame ionization detector (GC×GC-MS/FID) gives access to valuable information related to industrial quality. However, without accurate quantitative data, results transferability over time and across laboratories is prevented. The study applies quantitative volatilomics by multiple headspace solid phase microextraction (MHS-SPME) to a large selection of hazelnut samples (Corylus avellana L. n = 207) representing the top-quality selection of interest for the confectionery industry. By untargeted and targeted fingerprinting, performant classification models validate the role of chemical patterns strongly correlated to quality parameters (i.e., botanical/geographical origin, post-harvest practices, storage time and conditions). By quantification of marker analytes, Artificial Intelligence (AI) tools are derived: the augmented smelling based on sensomics with blueprint related to key-aroma compounds and spoilage odorant; decision-makers for rancidity level and storage quality; origin tracers. By reliable quantification AI can be applied with confidence and could be the driver for industrial strategies.

Rapid on-site detection of underground petroleum pipeline leaks and risk assessment using portable gas chromatography-mass spectrometry and solid phase microextraction.

Locating underground pipeline leaks can be challenging due to their hidden nature and variable terrain conditions. To sample soil gas, solid-phase microextraction (SPME) was employed, and a portable gas chromatography/mass spectrometry (GC/MS) was used to detect the presence and concentrations of petroleum hydrocarbon volatile organic compounds (pH-VOCs), including benzene, toluene, ethylbenzene, and xylene (BTEX). We optimized the extraction method through benchtop studies using SPME. The appropriate fibre materials and exposure time were selected for each BTEX compound. Before applying SPME, we preconditioned the soil vapour samples by keeping the temperature at around 4 °C and using ethanol as a desorbing agent and moisture filters to minimize the impact of moisture. To conduct this optimisation, airbags were applied to condition the soil vapour samples and SPME sampling. By conditioning the samples using this method, we were able to improve analytical efficiency and accuracy while minimizing environmental impacts, resulting in more reliable research data in the field. The study employed portable GC/MS data to assess the concentration distribution of BTEX in soil vapour samples obtained from 1.5 m below the ground surface at 10 subsurface vapour monitoring locations at the leak site. After optimization, the detection limits of BTEX were almost 100 µg/m3, and the measurement repeatabilities were approximately 5% and 15% for BTEX standards in the laboratory and soil vapour samples in the field, respectively. The soil vapour samples showed a hotspot region with high BTEX concentrations, reaching 30 mg/m3, indicating a diesel return pipeline leak caused by a gasket failure in a flange. The prompt detection of the leak source was critical in minimizing environmental impact and worker safety hazards.

Quality assessment of rose tea with different drying methods based on physicochemical properties, HS-SPME-GC-MS, and GC-IMS.

The purpose of this study is to compare the physicochemical properties and volatile flavor compounds of rose tea obtained by the methods of normal temperature drying, hot-air drying (HAD), and vacuum freeze-drying (VFD) and to evaluate the quality of rose tea. The physicochemical results showed that the content of ascorbic acid (VC) and the pH value was the highest in rose tea obtained by HAD. The contents of anthocyanin, proanthocyanidins, and total phenols were highest in rose tea obtained by VFD. However, there was no significant difference in total flavonoids between drying methods. The volatile organic compounds (VOCs) in rose tea with different drying methods were analyzed by headspace solid-phase microextraction-gas chromatography-mass spectroscopy (HS-SPME-GC-MS) and HS GC-ion mobility spectroscopy (HS-GC-IMS), and the flavor fingerprint of rose tea was established by principal component analysis (PCA). The concentration of VOCs in rose tea varied greatly with different drying methods. The main flavor compounds of rose tea were alcohols, esters, aldehydes, and terpenoids. HS-GC-IMS was used for the identification of volatile flavor compounds of rose tea, thereby helping to assess the quality of rose tea. In addition, the rose tea samples with different drying methods were well distinguished by PCA. This study deepens the understanding of the physicochemical properties and volatile flavor compounds of rose tea with different drying methods and provides a reference for the identification of rose tea with different drying methods. PRACTICAL APPLICATION: This study deepens the understanding of the physicochemical properties and volatile flavor compounds of rose tea with different drying methods and provides a reference for the identification of rose tea with different drying methods. It also provides an effective theoretical basis for consumers to buy rose tea.

Occurrence of volatile contaminants in recycled poly(ethylene terephthalate) by HS-SPME-GC×GC-QTOF-MS combined with chemometrics for authenticity assessment of geographical recycling regions.

A comparison was performed on various methods detecting the volatile contaminants (VCs) in recycled poly(ethylene terephthalate) (rPET) flakes, the results demonstrated that head-space solid phase micro-extraction combined with comprehensive two-dimensional gas chromatograph-tandem quadrupole-time-of-flight mass spectrometry (HS-SPME-GC×GC-QTOF-MS) was a sensitive, effective, accurate method, and successfully applied to analyze 57 rPET flakes collected from different recycling plants in China. A total of 212 VCs were tentatively identified, and the possible source were associated with plastic, food, and cosmetics. 45 VCs are classified as high-priority compounds with toxicity level IV or V and may pose a risk to human health. Combined chemometrics for further analysis revealed that significant differences among these three geographical recycling regions. 6, 7, and 6 volatile markers were chosen based on VIP values and S-plot among plant1 plant 2 and plant 3, respectively. The markers differed significantly between recycled rPET samples in three geographical recycling regions based on chemometrics analysis. The initial classification rate and cross-validation accuracy were 100% on the identified VCs. These significant differences demonstrate that a systematic study is needed to obtain a comprehensive data on the contamination of rPET for food contact applications in China.

Quality assessment of royal jelly based on physicochemical properties and flavor profiles using HS-SPME-GC/MS combined with electronic nose and electronic tongue analyses.

Royal jelly (RJ) is known for its unique flavor and nutritional value. However, the flavor changes of RJ during storage remain unclear. In this work, the flavor profiles of RJ during storage were evaluated by using headspace solid-phase micro-extraction gas chromatography-mass spectrometry (HS-SPME-GC/MS) combined with both electronic nose and electronic tongue analyses. Results revealed that the moisture, water-soluble protein, and whiteness were changed significantly at 25 °C. The holistic variation of RJ flavor exhibited evident distinction based on principal component analysis with electronic nose and electronic tongue. Among the total of 37 volatile compounds identified in RJ, the octanoic acid showed the highest contents of 47.61 % at 25 °C in 21 d. Seven volatile compounds, i.e., 2(3H)-furanone,5-butyldihydro-, 2-heptanone, trans-ß-ocimene, 2-nonen-4-one, 2-nonanone, methyl benzoate, and 2-octenoic acid (E), contributed largely to the typical overall flavor of RJ. This work provides an improved understanding of the flavor change of RJ during storage.

High-Throughput Assessment of the Abiotic Stability of Test Chemicals in In Vitro Bioassays.

Abiotic stability of chemicals is not routinely tested prior to performing in vitro bioassays, although abiotic degradation can reduce the concentration of test chemicals leading to the formation of active or inactive transformation products, which may lead to misinterpretation of bioassay results. A high-throughput workflow was developed to measure the abiotic stability of 22 test chemicals in protein-rich aqueous media under typical bioassay conditions at 37 °C for 48 h. These test chemicals were degradable in the environment according to a literature review. The chemicals were extracted from the exposure media at different time points using a novel 96-pin solid-phase microextraction. The conditions were varied to differentiate between various reaction mechanisms. For most hydrolyzable chemicals, pH-dependent degradation in phosphate-buffered saline indicated that acid-catalyzed hydrolysis was less important than reactions with hydroxide ions. Reactions with proteins were mainly responsible for the depletion of the test chemicals in the media, which was simulated by bovine serum albumin (BSA) and glutathione (GSH). 1,2-Benzisothiazol-3(2H)-one, 2-methyl-4-isothiazolinone, and l-sulforaphane reacted almost instantaneously with GSH but not with BSA, indicating that GSH is a good proxy for reactivity with electrophilic amino acids but may overestimate the actual reaction with three-dimensional proteins. Chemicals such as hydroquinones or polyunsaturated chemicals are prone to autoxidation, but this reaction is difficult to differentiate from hydrolysis and could not be simulated by the oxidant N-bromosuccinimide. Photodegradation played a minor role because cells are exposed in incubators in the dark and simulations with high light intensities did not yield realistic degradation. Stability predictions from various in silico prediction models for environmental conditions can give initial indications of the stability but were not always consistent with the experimental stability in bioassays. As the presented workflow can be performed in high throughput under realistic bioassay conditions, it can be used to provide an experimental database for developing bioassay-specific stability prediction models.

Exploring multiple-cumulative trapping solid-phase microextraction coupled to gas chromatography-mass spectrometry for quality and authenticity assessment of olive oil.

This study explores the potential of an innovative multi-cumulative trapping headspace solid-phase microextraction approach coupled with untargeted data analysis to enhance the information provided by aroma profiling of virgin olive oil. Sixty-nine samples of different olive oil commercial categories (extra-virgin, virgin and lampante oil) and different geographical origins were analysed using this novel workflow. The results from each sample were aligned and compared using for the first time a tile-based approach to enable the mining of all of the raw data within the chemometrics platform without any pre-processing methods. The data matrix obtained allowed the extraction of multiple-level information from the volatile profile of the samples. Not only was it possible to classify the samples within the commercial category that they belonged to, but the same data also provided interesting information regarding the geographical origin of the extra-virgin olive oil.

Essential and non-essential elements, and volatile organic compounds for the discrimination of twenty-three sweet cherry cultivars from Fundão, Portugal.

The mineral contents and volatile profiles of 23 sweet cherry cultivars were determined. A total of 27 minerals were determined by ICP-MS and flame atomic absorption spectrometry, including 12 essential and 15 non-essential elements. K was the most abundant in all cultivars, while Tl was the one found in the smallest amounts. A total of 66 volatiles were identified using SPME/GC-MS, including 16 aldehydes, 23 alcohols, 6 ketones, 6 esters, 8 monoterpenes, 3 norisoprenoids, 2 hydrocarbons and 2 acids. Benzaldehyde, hexanal, nonanal, benzyl alcohol, (E)-2-hexen-1-ol, 1-hexanol, (Z)-2-hexen-1-ol, 2-ethyl-1-hexanol, linalool, α-terpineol and α-ionone were the major ones. Qualitative and quantitative differences were observed among the cultivars, which influenced nutritional potential and aroma. Cherries from Fundão region contain high concentrations of phytochemicals and nutritional components. 4-84, Burlat and Celeste might be considered some of the most interesting cultivars, since they are rich in essential minerals and present high diversity in volatiles.

Volatile Organic Compounds, Indole, and Biogenic Amines Assessment in Two Mediterranean Irciniidae (Porifera, Demospongiae).

Solid phase microextraction (SPME) coupled to gas chromatography-mass spectrometry (GC-MS) was employed for the headspace determination of the volatile organic fraction emitted by two of the most common Mediterranean demosponges, Ircinia variabilis and Sarcotragus spinosulus, and of indole and some biogenic amines released by sponges in an aqueous medium. A total of 50/30 µm divinylbenzene/carboxen/polydimethylsiloxane and 75 µm carboxen/polydimethylsiloxane fibers were used for the headspace extraction of low molecular weight sulfur compounds from a hermetically sealed vial containing sponge fragments, while the direct immersion determination of indole and biogenic amines was performed. The biogenic amines were extracted after in-solution derivatization with isobutyl chloroformate. All analytical parameters (linearity, limits of detection, and quantification, precision, and recovery) were evaluated for indole and biogenic amines. SPME-GC-MS proved to be a reliable means of highlighting the differences between molecules released by different sponges, principally responsible for their smell. The combined approaches allowed the identification of several volatile compounds in the headspace and other molecules released by the sponges in an aqueous medium, including indole and the BAs cadaverine, histamine, isobutylamine, isopentylamine, propylamine, 2-phenylethylamine, putrescine and tryptamine. The results obtained represent a further contribution to the picture of odoriferous molecules secreted by sponges.

Risk Assessment of Passive Smoking Based on Analysis of Hair Nicotine and Cotinine as Exposure Biomarkers by In-Tube Solid-Phase Microextraction Coupled On-Line to LC-MS/MS.

Passive smoking due to environmental tobacco smoke is a serious public health concern because it increases the risk of lung cancer and cardiovascular disease. However, the current status and effect of passive smoking in various lifestyles are not fully understood. In this study, we measured hair nicotine and cotinine levels as exposure biomarkers in non-smokers and assessed the risk from the actual situation of passive smoking in different lifestyle environments. Nicotine and cotinine contents in hair samples of 110 non-smoker subjects were measured by in-tube solid-phase microextraction with on-line coupling to liquid chromatography-tandem mass spectrometry, and self-reported lifestyle questionnaires were completed by the subjects. Nicotine and cotinine were detected at concentrations of 1.38 ng mg-1 and 12.8 pg mg-1 respectively in the hair of non-smokers, with levels significantly higher in subjects who reported being sensitive to tobacco smoke exposure. These levels were also affected by type of food intake and cooking method. Nicotine and cotinine in hair are useful biomarkers for assessing the effects of passive smoking on long-term exposure to environmental tobacco smoke, and our analytical methods can measure these exposure levels in people who are unaware of passive smoking. The results of this study suggest that the environment and places of tobacco smoke exposure and the lifestyle behaviors therein are important for the health effects of passive smoking.

Assessment of gas-phase concentrations of organophosphate flame retardants at the material surface using a midget emission cell coupled to solid-phase microextraction.

Actual methods for on-site measurement of gaseous concentrations of Semi-Volatile Organic Compounds (SVOCs) at the material surface (y0) are not yet sufficiently developed mainly due to sampling difficulties. These concentrations are the key data to improve knowledge about indoor sources and human exposure to SVOCs. To the end, a specific emission cell coupled to solid-phase microextraction (SPME) was developed. The main challenge with this method is calibration because of very low volatility of SVOCs and static sampling mode. In this study, a generating system of organophosphate flame retardants (OFRs) using polyurethane foam as source combined with an active sampling method with Tenax tubes was proposed as a novel calibration device for SPME-based method. The generating system delivered stable OFR concentrations after 190 h of operation with a variation not exceeding ±5%. It allowed to obtain robust calibrations for tris-(2-chloropropyl)-phosphate (TCPP) and tri-butyl-phosphate (TBP) measured with the emission cell coupled to SPME-based method, define the optimal sampling requirements and achieve reproducible and accurate measurements of y0 at µg.m-3 level. TCPP and TBP gas-phase concentrations at the polyurethane foam surface (y0) were followed up over more 228 days under controlled temperature conditions. A high stability of these concentrations was observed showing that polyurethane foam acts as a stable and continuous source of organophosphate flame retardants indoors. This novel method should be useful for assessing the dynamic of emissions from indoor sources and potential exposure to SVOCs in indoor environments.

A sensitive microextraction by packed sorbent-gas chromatography-mass spectrometry method for the assessment of polycyclic aromatic hydrocarbons contamination in Antarctic surface snow.

For the first time an eco-friendly method involving microextraction by packed sorbent (MEPS) coupled to gas chromatography-mass spectrometry (GC-MS) was developed for the determination of the 16 US-EPA priority pollutant polycyclic aromatic hydrocarbons (PAHs) as indicators of anthropogenic contamination in snow samples collected in polar regions. MEPS was carried out by using C8 sorbent material packed in a barrel insert and needle (BIN) and integrated in the eVol® semi-automatic device. For optimization purposes a Face Centred Design and the multicriteria method of the desirability functions were performed to investigate the effect of some parameters affecting the MEPS extraction efficiency, i.e. the number of loading cycles and the number of elution cycles. The developed MEPS-GC-MS method proved to be suitable for PAHs analysis at ultra-trace level by extracting small sample volumes achieving detection limits for 16 PAHs in the 0.3-5 ng L-1 range, repeatability and intermediate precision below 11% and 15%, respectively, and good recovery rates in the 77.6 (±0.1)-120.8 (±0.1)% range for spiked blank snow samples. Enrichment factors in the 64 (±7)-129 (±18) range were calculated. Finally, the proposed method was successfully applied to the determination of PAHs in surface snow samples collected in 2020-2021 from four locations of Northern Victoria Land, Antarctica. Local emission sources such as ships and research stations were found to influence PAHs concentrations in the surface snow.

Solid-phase microextraction for assessment of plasma protein binding, a complement to rapid equilibrium dialysis.

Aim: Determination of plasma protein binding (PPB) is considered vital for better understanding of pharmacokinetic and pharmacodynamic activities of drugs due to the role of free concentration in pharmacological response. Methodology & results: Solid-phase microextraction (SPME) was investigated for measurement of PPB from biological matrices and compared with a gold standard approach (rapid equilibrium dialysis [RED]). Discussion & conclusion: SPME-derived values of PPB correlated well with literature values, and those determined by RED. Respectively, average protein binding across three concentrations by RED and SPME was 33.1 and 31.7% for metoprolol, 89.0 and 86.6% for propranolol and 99.2 and 99.0% for diclofenac. This study generates some evidence for SPME as an alternative platform for the determination of PPB.

Assessment of solid phase microextraction as a sample preparation tool for untargeted analysis of brain tissue using liquid chromatography-mass spectrometry.

This work presents an evaluation of solid-phase microextraction (SPME) SPME in combination with liquid chromatography-high resolution mass spectrometry (LC-HRMS) as an analytical approach for untargeted brain analysis. The study included a characterization of the metabolite coverage provided by C18, mixed-mode (MM, with benzene sulfonic acid and C18 functionalities), and hydrophilic lipophilic balanced (HLB) particles as sorbents in SPME coatings after extraction from cow brain homogenate at static conditions. The effects of desorption solvent, extraction time, and chromatographic modes on the metabolite features detected were investigated. Method precision and absolute matrix effects were also assessed. Among the main findings of this work, it was observed that all three tested coating chemistries were able to provide comparable brain tissue information. HLB provided higher responses for polar metabolites; however, as these fibers were prepared in-house, higher inter-fiber relative standard deviations were also observed. C18 and HLB coatings offered similar responses with respect to lipid-related features, whereas MM and C18 provided the best results in terms of method precision. Our results also showed that the use of methanol is essential for effective desorption of non-polar metabolites. Using a reversed-phase chromatographic method, an average of 800 and 1200 brain metabolite features detected in positive and negative modes, respectively, met inter-fibre RSD values below 30% (n=4) after removal of fibre and solvent artefacts from the associated datasets. For features detected using a lipidomics method, a total of 900 and 1800 features detected using C18 fibers in positive and negative mode, respectively, met the same criteria. In terms of absolute matrix effects, the majority of the model metabolites tested showed values between 80 and 120%, which are within the acceptable range. Overall, the findings of this work lay the foundation for further optimization of parameters for SPME-LC-HRMS methods suitable for in vivo and ex vivo brain (and other tissue) untargeted studies, and support the applicability of this approach for non-destructive tissue metabolomics.