References of "Purcaro, Giorgia"
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See detailTowards a regulatory method using multidimensional techniques. The mineral oil case
Purcaro, Giorgia ULiege; Collard, Maurine; Pantó, Sebastiano

Conference (2019, May)

The presence of mineral oil hydrocarbons (MOH) in food was first highlighted by Biedermann and co-workers in 1989 (Biedermann et al, 1989), but the main discussion started 20 years later when the same ... [more ▼]

The presence of mineral oil hydrocarbons (MOH) in food was first highlighted by Biedermann and co-workers in 1989 (Biedermann et al, 1989), but the main discussion started 20 years later when the same authors related the presence of high amount of MOH to the use of recycled fibers for food contact material (Biedermann et al., 2009). The analysis of such a contaminant in food is a challenging task, mainly due to the high complexity of the matrices and the high affinity with the lipid fraction and many of its components. Due to this challenge the use of powerful confirmatory techniques is required. The European Food Safety Authority (EFSA, 2012) confirmed the use of on-line LC-GC/FID as the most effective method for the analysis of MOH, but the presence of false positive and the doubts on the nature of the chromatographic hump originated with this analysis remain. Therefore, this analysis needs to be supported by a most powerful technique for confirmatory purposes. Although, some authors look toward mass spectrometry, GC×GC-MS/FID seems to be the most promising solution, as also stress by the EFSA. However, additional proof of concepts need to be provided to convince the most sceptics. This contribution works on this direction to provide additional and conclusive support to confirm the valid use of GC×GC as a EU regulated confirmatory method. [less ▲]

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See detailQuantification of estrogenic compounds as pyridine-3-sulfonyl derivatives by UHPLC-ESI-MS/MS at trace level in different aqueous matrices
Glineur, Alex ULiege; Nott, Katherine; Purcaro, Giorgia ULiege

Conference (2019, May)

Natural estrogens (estrone: E1, 17-β-estradiol: E2, estriol: E3) and synthetic estrogen (17-α-ethinylestradiol: EE2) are powerful endocrine disruptors harmful for aquatic wildlife and human at extremely ... [more ▼]

Natural estrogens (estrone: E1, 17-β-estradiol: E2, estriol: E3) and synthetic estrogen (17-α-ethinylestradiol: EE2) are powerful endocrine disruptors harmful for aquatic wildlife and human at extremely low concentration. Therefore, the European Commission included these molecules in a watch list (2018) regarding emerging aquatic pollutants, proposing maximum detection limits of 0.035 ng/L for EE2 and 0.4 for E1 and E2. Attaining these limits represents a challenge even with the up-to-date analytical tools. In this work a UHPLC-ESI-MS/MS method allowing the quantification of E1, E2, E3 and EE2 in water was developed. Estrogenic compounds were derivatized using pyridine-3-sulfonyl chloride to enhance the response in ESI (+). This derivatization procedure allowed to obtain at least two transitions for each analyte which were proved to be specific and hence selected for quantification and confirmation. At first, a method dedicated to clean aqueous matrices (groundwater, tap water) was developed and validated. This method consisted in a single step of SPE extraction and was suitable to reach low LODs. However, as underlined by the EU in the watch list, surface water should be monitored as well to have an overview of the presence and the transport of E1, E2, E3 and EE2 in the environment. The analysis of such a complex matrix required the optimization of an additional clean-up step to achieve the sensitivity required, allowing at the same time a high sample throughput. [less ▲]

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See detailA comparative study on the effect of vacuum on HS-SPME of olive oil volatiles
Mascrez, Steven ULiege; Psillakis, Elia; Purcaro, Giorgia ULiege

Conference (2019, May)

Solid-phase microextraction (SPME) is a simple, effective and selective technique for the analysis of volatiles and semi-volatiles compounds. However, frequently a long time is requested to reach the ... [more ▼]

Solid-phase microextraction (SPME) is a simple, effective and selective technique for the analysis of volatiles and semi-volatiles compounds. However, frequently a long time is requested to reach the equilibrium condition to maximize the extraction efficiency, thus pre-equilibrium conditions are preferred as a compromise in term of throughput and sensitivity. Beside other strategy to improve the kinetic extraction, vacuum has been recently successfully proposed with the main advantages to speed up the extraction without increasing the temperature and thus preserving the sample profile. In this work Vacuum-SPME has been investigated for the first time for the analysis of a fat matrix, namely olive oil, for the determination of its aroma profile. Gas chromatography coupled to a single quadrupole mass spectrometry was used for the final determination. A three variables (k= 3; temperature, extraction time and sample mass) inscribed rotatable central composite experimental design was used to optimize the sampling conditions. A series of compounds, covering the entire range of volatility and a wide chemical structure, were selected to compare atmospheric and under vacuum conditions. [less ▲]

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See detailImportance du type d'absorbant pour l'échantillonnage des volatils : application sur les cultures bactériennes et l'haleine
Zanella, Delphine ULiege; Franchina, Flavio ULiege; Stefanuto, Pierre-Hugues ULiege et al

Poster (2019, March)

Les composés organiques volatils bactériens (VOC) sont considérés comme des biomarqueurs sensibles et spécifiques pour le phénotypage bactérien dans les biofluides humains (haleine, sang, urine, etc.) et ... [more ▼]

Les composés organiques volatils bactériens (VOC) sont considérés comme des biomarqueurs sensibles et spécifiques pour le phénotypage bactérien dans les biofluides humains (haleine, sang, urine, etc.) et dans les milieux de culture. La possibilité d'utiliser les VOCs pour l'identification bactérienne ouvre de nouvelles possibilités pour la mise au point de techniques de diagnostiques plus efficaces. Outre les différences biologiques des environnements in-vivo et in-vitro, il est essentiel d'utiliser la même technique d’échantillonnage pour la caractérisation et la validation de biomarqueurs. Dans cette étude, la chromatographie gazeuse bidimensionnelle couplée à la spectrométrie de masse (GC×GC-MS) a été utilisée pour comparer et évaluer différents adsorbants de tubes de désorption thermique pour l’échantillonnage des VOCs. Plus précisément, les paramètres suivants ont été évalués pour chaque adsorbant: sensibilité, sélectivité, reproductibilité et linéarité. Cinq adsorbants différents (Carbopack Y, X, B, Carboxen 1000 et Tenax), utilisés individuellement ou en combinaison, ont été testés sur un mélange de standards (15 composés). Les meilleures sensibilité et reproductibilité ont été obtenues pour les tubes conditionnés avec du Tenax. Les deux tubes de désorption thermique les plus performants, Tenax et Carbopack Y + X + Carboxen 1000, ont également été évalués sur des cultures de E. coli, S. aureus et P. aeruginosa. Ces deux types de tubes ont pu distinguer les 3 types de culture bactérienne, mais une amélioration de la sensibilité et de la reproductibilité a été obtenue avec les tubes Tenax. Une comparaison similaire sur les performances des tubes a été effectuée sur des échantillons d'haleine. [less ▲]

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See detailEvaluation of different adsorbent materials for the untargeted and targeted bacterial VOC analysis using GC×GC-MS
Franchina, Flavio ULiege; Purcaro, Giorgia ULiege; Burklund, A. et al

in Analytica Chimica Acta (2019), 1066

The analysis of bacterial volatile organic compounds has gained attraction as a non-invasive way to identify disease-causing organisms, given that bacteria have unique metabolisms and volatile metabolic ... [more ▼]

The analysis of bacterial volatile organic compounds has gained attraction as a non-invasive way to identify disease-causing organisms, given that bacteria have unique metabolisms and volatile metabolic byproducts. In the present research, different adsorbent materials (Carbopack Y, X, B, Carboxen 1000 and Tenax TA), packed singularly or in combination, were compared in terms of sampling performance (sensitivity, repeatability and selectivity) for the extraction of standards and bacterial volatile metabolites in vitro (from Staphylococcus aureus, Pseudomonas aeruginosa, and Escherichia coli). After extraction, bacterial volatile organic compounds were desorbed and analyzed in a comprehensive two-dimensional gas chromatography system coupled to a time-of-flight mass spectrometer (GC GC-ToF MS). The results show that Tenax has the greater ability to extract the standard mix as well as volatile organic compounds with better repeatability (4e26 RSD%), higher sensitivity (on average ~24 fold) compared to Carbopack Y, X and Carboxen 1000 tube, which followed in terms of performance. In addition, Tenax confirmed the best sensitivity and discriminatory power with no misclassification in the untargeted and unsupervised analysis for the differentiation of the bacterial species. [less ▲]

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See detailBreath metabolome of mice infected with Pseudomonas aeruginosa
Purcaro, Giorgia ULiege; Nasir, M.; Franchina, Flavio ULiege et al

in Metabolomics (2019), 15(1),

Introduction: The measurement of specific volatile organic compounds in breath has been proposed as a potential diagnostic for a variety of diseases. The most well-studied bacterial lung infection in the ... [more ▼]

Introduction: The measurement of specific volatile organic compounds in breath has been proposed as a potential diagnostic for a variety of diseases. The most well-studied bacterial lung infection in the breath field is that caused by Pseudomonas aeruginosa. Objectives: To determine a discriminatory core of molecules in the “breath-print” of mice during a lung infection with four strains of P. aeruginosa (PAO1, PA14, PAK, PA7). Furthermore, we attempted to extrapolate a strain-specific “breath-print” signature to investigate the possibility of recapitulating the genetic phylogenetic groups (Stewart et al. Pathog Dis 71(1), 20–25, 2014. https://doi.org/10.1111/2049-632X.12107). Methods: Breath was collected into a Tedlar bag and shortly after drawn into a thermal desorption tube. The latter was then analyzed into a comprehensive multidimensional gas chromatography coupled with a time-of-flight mass spectrometer. Random forest algorithm was used for selecting the most discriminatory features and creating a prediction model. Results: Three hundred and one molecules were significantly different between animals infected with P. aeruginosa, and those given a sham infection (PBS) or inoculated with UV-killed P. aeruginosa. Of those, nine metabolites could be used to discriminate between the three groups with an accuracy of 81%. Hierarchical clustering showed that the signature from breath was due to a specific response to live bacteria instead of a generic infection response. Furthermore, we identified ten additional volatile metabolites that could differentiate mice infected with different strains of P. aeruginosa. A phylogram generated from the ten metabolites showed that PAO1 and PA7 were the most distinct group, while PAK and PA14 were interspersed between the former two groups. Conclusions: To the best of our knowledge, this is the first study to report on a ‘core’ murine breath print, as well as, strain level differences between the compounds in breath. We provide identifications (by running commercially available analytical standards) to five breath compounds that are predictive of P. aeruginosa infection. © 2019, Springer Science+Business Media, LLC, part of Springer Nature. [less ▲]

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See detailImportance of sorbent material selection for VOCs sampling: application on bacterial cultures and breath
Franchina, Flavio ULiege; Zanella, Delphine ULiege; Stefanuto, Pierre-Hugues ULiege et al

Scientific conference (2018, November 08)

Bacterial volatile organic compounds (VOCs) have been considered as sensitive and specific biomarkers for bacterial phenotyping in both human biofluids (breath, blood, urine, etc.) and culture media. The ... [more ▼]

Bacterial volatile organic compounds (VOCs) have been considered as sensitive and specific biomarkers for bacterial phenotyping in both human biofluids (breath, blood, urine, etc.) and culture media. The possibility of using VOCs markers for bacterial identification would open a new frontier for developing more efficient diagnostic techniques of infections. Besides the biological differences in in vivo/in vitro environments, the importance of using the same sampling technique and sorbent phase is crucial for the translation and validation of biomarker discovery. In the present contribution, GC×GC-MS was exploited to compare and evaluate different adsorption materials for thermal desorption tubes for VOCs sampling. Specifically, the following parameters were evaluated: sensitivity, selectivity, reproducibility and linear range. Five different adsorbent materials (Carbopack Y, X, B, Carboxen 1000 and Tenax), packed singularly or in combination, were tested on a standard mixture (15 compounds). The tubes packed with Tenax showed the best reproducibility (max 14% RSD) and sensitivity, with ~24 average fold increase compared to Carbopack Y+X+Carboxen 1000, which was second in terms of sensitivity. The two better performing thermal desorption tubes, Tenax and Carbopack Y+X+Carboxen 1000, was also evaluated on E. coli, S. aureus, and P. aeruginosa cultures. Both tubes were able to discriminate between the 3 culture types, but improved sensitivity and reproducibility were obtained with Tenax tubes. A similar comparison on tube performances was carried out on breath samples. [less ▲]

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See detailA breathprint of influenza a virus infection in the ferret model
Kormuth, K; Franchina, Flavio ULiege; Le Sage, V et al

Poster (2018, November 08)

Influenza viruses (IV) pose a major public health concern, since they are highly contagious and still have a high global annual mortality. Current diagnostic methods are slow or have high error rates ... [more ▼]

Influenza viruses (IV) pose a major public health concern, since they are highly contagious and still have a high global annual mortality. Current diagnostic methods are slow or have high error rates; therefore, a rapid detection tool is highly desirable to inform clinical management. Exhaled breath is a useful diagnostic in a number of diseases. In this work, we examined the exhaled breath of six ferrets collected pre- and post-IV infection. Exhaled breath analysis was carried out using a comprehensive two-dimensional gas chromatography (GC×GC) hyphenated with a time-of-flight mass spectrometer (ToF MS). Random Forest, a non-parametric machine learning algorithm, was used to select the most relevant diagnostic volatile organic compound (VOC) features and build the model using a cross-validation approach, obtaining an accuracy of 0.973 (out of 1.000). Using this approach, we defined 31 VOC features, which together produce a profile capable of discriminating between uninfected and IV-infected ferrets. Further characterization revealed an abundance of hydrocarbons, which is consistent with increased oxidative stress known to occur during viral infection. Our study is the first of its kind to define a unique exhaled breath signature for influenza infection in ferrets and will be useful for development of a rapid precision diagnostic technique. [less ▲]

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See detailAnalytical techniques for MOSH and MOAH quantification and identification
Purcaro, Giorgia ULiege

Scientific conference (2018, November)

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See detailSPME-GC×GC-TOF MS fingerprint of virally-infected cell culture: Sample preparation optimization and data processing evaluation
Purcaro, Giorgia ULiege; Stefanuto, Pierre-Hugues ULiege; Flavio, Franchina et al

in Analytica Chimica Acta (2018)

Untargeted metabolomics study of volatile organic compounds produced by different cell cultures is a field that has gained increasing attention over the years. Solid-phase microextraction has been the ... [more ▼]

Untargeted metabolomics study of volatile organic compounds produced by different cell cultures is a field that has gained increasing attention over the years. Solid-phase microextraction has been the sampling technique of choice for most of the applications mainly due to its simplicity to implement. However, a careful optimization of the analytical conditions is necessary to obtain the best performances, which are highly matrix-dependent. In this work, five different solid-phase microextraction fibers were compared for the analysis of the volatiles produced by cell culture infected with the human respiratory syncytial virus. A central composite design was applied to determine the best time-temperature combination to maximize the extraction efficiency and the salting-out effect was evaluated as well. The linearity of the optimized method, along with limits of detection and quantification and repeatability was assessed. Finally, the effect of i) different normalization techniques (i.e. z-score and probabilistic quotient normalization), ii) data transformation (i.e. in logarithmic scale), and iii) different feature selection algorithms (i.e. Fisher ratio and random forest) on the capability of discriminating between infected and not-infected cell culture was evaluated. [less ▲]

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See detailEnvironmental conditions influence the biochemical properties of the fruiting bodies of Tuber magnatum Pico
Vita, F.; Franchina, Flavio ULiege; Taiti, C. et al

in Scientific Reports (2018), 8(1),

The influences of various factors, including the symbiosis established with the roots of specific tree species, on the production of volatiles in the fruiting bodies of Tuber magnatum have not been ... [more ▼]

The influences of various factors, including the symbiosis established with the roots of specific tree species, on the production of volatiles in the fruiting bodies of Tuber magnatum have not been investigated yet. Volatiles in T. magnatum fruiting bodies were quantitatively and qualitatively determined by both PTR-MS and GC-MS in order to compare the accuracy of the two methods. An electronic nose was also used to characterize truffle samples. The influence of environmental changes on the antioxidant capabilities of fruiting bodies was also determined. Statistically significant differences were found between fruiting bodies with different origins. The relationship between the quality of white truffle fruiting bodies and their specific host plant is described along with an analysis of metabolites other than VOCs that have ecological roles. Our results indicate that the geographical origin (Italy and Istria) of the fruiting bodies is correlated with the quantity and quality of volatiles and various antioxidant metabolites. This is the first report characterizing antioxidant compounds other than VOCs in white truffles. The correlation between geographical origin and antioxidant contents suggests that these compounds may be useful for certifying the geographical origin of truffles. © 2018 The Author(s). [less ▲]

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See detailInvestigation of mycobacteria fatty acid profile using different ionization energies in GC–MS
Beccaria, M.; Franchina, Flavio ULiege; Nasir, M. et al

in Analytical and Bioanalytical Chemistry (2018), 410(30), 7987-7996

Gas chromatography (GC) coupled with electron ionization (EI) mass spectrometry (MS) is a well-established technique for the analysis of volatile and semi-volatile compounds. The main advantage is the ... [more ▼]

Gas chromatography (GC) coupled with electron ionization (EI) mass spectrometry (MS) is a well-established technique for the analysis of volatile and semi-volatile compounds. The main advantage is the highly repeatable fragmentation of the compounds into the ion source, generating intense and diagnostic fragmentation when the ionization is performed at 70 eV; this is considered the standard ionization condition and has been used for creating many established databases, which are of great support in the analyte identification process. However, such an intense fragmentation often causes the loss of the molecular ion or more diagnostic ions, which can be detrimental for the identification of homologous series or isomers, as for instance fatty acids. To obtain this information chemical or soft ionization can be used, but dedicated ion sources and conditions are required. In this work, we explored different ionization voltages in GC–EI–MS to preserve the intensity of the molecular ion using a conventional quadrupole MS. Twenty, 30, 50, and 70 eV were tested using a mixture of fatty acid methyl esters standards. Intensity and repeatability of the most informative ions were compared. Twenty and 70 eV were then used to analyze the fatty acid composition of six different strains of mycobacteria. Two approaches were used for elaborating the data: (1) a single average spectrum of the entire chromatogram was derived, which can be considered (in terms of concept) as a direct EI–MS analysis; (2) the actual chromatographic separation of the compounds was considered after automatic alignment. The results obtained are discussed herein. [Figure not available: see fulltext.]. © 2018, Springer-Verlag GmbH Germany, part of Springer Nature. [less ▲]

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See detailExhaled human breath analysis in active pulmonary tuberculosis diagnostics by comprehensive gas chromatography-mass spectrometry and chemometric techniques
Beccaria, M.; Bobak, C.; Maitshotlo, B. et al

in Journal of Breath Research (2018), 13(1), 016005

Tuberculosis (TB) is the deadliest infectious disease, and yet accurate diagnostics for the disease are unavailable for many subpopulations. In this study, we investigate the possibility of using human ... [more ▼]

Tuberculosis (TB) is the deadliest infectious disease, and yet accurate diagnostics for the disease are unavailable for many subpopulations. In this study, we investigate the possibility of using human breath for the diagnosis of active TB among TB suspect patients, considering also several risk factors for TB for smokers and those with human immunodeficiency virus (HIV). The analysis of exhaled breath, as an alternative to sputum-dependent tests, has the potential to provide a simple, fast, non-invasive, and readily available diagnostic service that could positively change TB detection. A total of 50 individuals from a clinic in South Africa were included in this pilot study. Human breath has been investigated in the setting of active TB using the thermal desorption-comprehensive two-dimensional gas chromatography-time of flight mass spectrometry methodology and chemometric techniques. From the entire spectrum of volatile metabolites in breath, three machine learning algorithms (support vector machines, partial least squares discriminant analysis, and random forest) to select discriminatory volatile molecules that could potentially be useful for active TB diagnosis were employed. Random forest showed the best overall performance, with sensitivities of 0.82 and 1.00 and specificities of 0.92 and 0.60 in the training and test data respectively. Unsupervised analysis of the compounds implicated by these algorithms suggests that they provide important information to cluster active TB from other patients. These results suggest that developing a non-invasive diagnostic for active TB using patient breath is a potentially rich avenue of research, including among patients with HIV comorbidities. [less ▲]

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See detailVolatile fingerprinting of Pseudomonas aeruginosa and respiratory syncytial virus infection in an in vitro cystic fibrosis co-infection model.
Purcaro, Giorgia ULiege; Rees, Christiaan A.; Melvin, Jeffrey A. et al

in Journal of Breath Research (2018), 12(4), 046001

Volatile molecules in exhaled breath represent potential biomarkers in the setting of infectious diseases, particularly those affecting the respiratory tract. In particular, Pseudomonas aeruginosa is a ... [more ▼]

Volatile molecules in exhaled breath represent potential biomarkers in the setting of infectious diseases, particularly those affecting the respiratory tract. In particular, Pseudomonas aeruginosa is a critically important respiratory pathogen in specific subsets of the population, such as those with cystic fibrosis (CF). Infections caused by P. aeruginosa can be particularly problematic when co-infection with respiratory syncytial virus (RSV) occurs, as this is correlated with the establishment of chronic P. aeruginosa infection. In the present study, we evaluate the volatile metabolites produced by P. aeruginosa (PAO1)-infected, RSV-infected, co-infected, or uninfected CF bronchial epithelial (CFBE) cells, in vitro. We identified a volatile metabolic signature that could discriminate between P. aeruginosa-infected and non-P. aeruginosa-infected CFBE with an area under the receiver operating characteristic curve (AUROC) of 0.850, using the machine learning algorithm random forest (RF). Although we could not discriminate between RSV-infected and non-RSV-infected CFBE (AUROC = 0.431), we note that sample classification probabilities for RSV-infected cell, generated using RF, were between those of uninfected CFBE and P. aeruginosa-infected CFBE, suggesting that RSV infection may result in a volatile metabolic profile that shares attributes with both of these groups. To more precisely elucidate the biological origins of the volatile metabolites that were discriminatory between P. aeruginosa-infected and non-P. aeruginosa-infected CFBE, we measured the volatile metabolites produced by P. aeruginosa grown in the absence of CFBE. Our findings suggest that the discriminatory metabolites produced likely result from the interaction of P. aeruginosa with the CFBE cells, rather than the metabolism of media components by the bacterium. Taken together, our findings support the notion that P. aeruginosa interacting with CFBE yields a particular volatile metabolic signature. Such a signature may have clinical utility in the monitoring of individuals with CF. [less ▲]

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See detailRaymond P. W. Scott: Introduction to analytical gas chromatography, 2nd ed.
Purcaro, Giorgia ULiege

in Analytical and Bioanalytical Chemistry (2018)

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See detailVolatile fingerprinting of human respiratory viruses from cell culture
Purcaro, Giorgia ULiege; Rees, Chris; Wieland-Alter, Wendy et al

in Journal of Breath Research (2017), 12(2),

Volatile metabolites are currently under investigation as potential biomarkers for the detection and identification of pathogenic microorganisms, including bacteria, fungi, and viruses. Unlike bacteria ... [more ▼]

Volatile metabolites are currently under investigation as potential biomarkers for the detection and identification of pathogenic microorganisms, including bacteria, fungi, and viruses. Unlike bacteria and fungi, which produce distinct volatile metabolic signatures associated with innate differences in both primary and secondary metabolic processes, viruses are wholly reliant on the metabolic machinery of infected cells for replication and propagation. In the present study, the ability of volatile metabolites to discriminate between respiratory cells infected and uninfected with virus, in vitro, was investigated. Two important respiratory viruses, namely respiratory syncytial virus (RSV) and influenza A virus (IAV), were evaluated. Data were analyzed using three different machine learning algorithms (random forest (RF), linear support vector machines (linear SVM), and partial least squares-discriminant analysis (PLS-DA)), with volatile metabolites identified from a training set used to predict sample classifications in a validation set. The discriminatory performances of RF, linear SVM, and PLS-DA were comparable for the comparison of IAV-infected versus uninfected cells, with area under the receiver operating characteristic curves (AUROCs) between 0.78 and 0.82, while RF and linear SVM demonstrated superior performance in the classification of RSV-infected versus uninfected cells (AUROCs between 0.80 and 0.84) relative to PLS-DA (0.61). A subset of discriminatory features were assigned putative compound identifications, with an overabundance of hydrocarbons observed in both RSV- and IAV-infected cell cultures relative to uninfected controls. This finding is consistent with increased oxidative stress, a process associated with viral infection of respiratory cells. [less ▲]

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See detailHighly informative multiclass profiling of lipids by ultra-high performance liquid chromatography – Low resolution (quadrupole) mass spectrometry by using electrospray ionization and atmospheric pressure chemical ionization interfaces
Beccaria, M.; Inferrera, V.; Rigano, F. et al

in Journal of Chromatography. A (2017), 1509

A simple, fast, and versatile method, using an ultra-high performance liquid chromatography system coupled with a low resolution (single quadrupole) mass spectrometer was optimized to perform multiclass ... [more ▼]

A simple, fast, and versatile method, using an ultra-high performance liquid chromatography system coupled with a low resolution (single quadrupole) mass spectrometer was optimized to perform multiclass lipid profiling of human plasma. Particular attention was made to develop a method suitable for both electrospray ionization and atmospheric pressure chemical ionization interfaces (sequentially in positive- and negative-ion mode), without any modification of the chromatographic conditions (mobile phase, flow-rate, gradient, etc.). Emphasis was given to the extrapolation of the structural information based on the fragmentation pattern obtained using atmospheric pressure chemical ionization interface, under each different ionization condition, highlighting the complementary information obtained using the electrospray ionization interface, of support for related molecule ions identification. Furthermore, mass spectra of phosphatidylserine and phosphatidylinositol obtained using the atmospheric pressure chemical ionization interface are reported and discussed for the first time. © 2017 Elsevier B.V. [less ▲]

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See detailMiniaturization of the QuEChERS Method in the Fast Gas Chromatography-Tandem Mass Spectrometry Analysis of Pesticide Residues in Vegetables
Zoccali, M.; Purcaro, Giorgia ULiege; Schepis, A. et al

in Food Analytical Methods (2017), 10(8), 2636-2645

Two reduced-scale quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedures, combined with fast gas chromatography-triple quadrupole mass spectrometry (GC-QqQ MS), were developed and then ... [more ▼]

Two reduced-scale quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedures, combined with fast gas chromatography-triple quadrupole mass spectrometry (GC-QqQ MS), were developed and then validated for the determination of 35 pesticides in different vegetable products (tomatoes, zucchini, red peppers, and lettuce). The proposed reduced-scale methods, involving the use of only 3 g of sample, were compared with an official European Union method, namely EN15662:2008, based on the use of a 10-g sample. Method validation was performed considering the following figures of merit: recovery, linearity, precision, matrix effects, and limits of detection and quantification. Specifically, recovery was in the 67–126% range, regression coefficients were between 0.991 and 0.999, and coefficients of variation were between 1 and 13% (at the 50 μg kg−1 level), while limits of quantification were always below European legislation residue limits. Additionally, the measurement of matrix effects confirmed the necessity of matrix-matched calibration. The developed QuEChERS GC-QqQ MS method is both simple and rapid (analysis of six samples in 2.5 h) and is sensitive enough for EU regulation purposes. To demonstrate the applicability of the proposed reduced-scale method, multi-residue analysis was performed on 20 samples. © 2017, Springer Science+Business Media New York. [less ▲]

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See detailIn-pipette solid-phase extraction prior to flow-modulation comprehensive two-dimensional gas chromatography with dual detection for the determination of minor components in vegetable oils
Barp, L.; Franchina, Flavio ULiege; Purcaro, Giorgia ULiege et al

in Talanta (2017), 165

The present research is based on the development of an effective, environmentally-friendly and low-cost method for investigation of minor components in vegetable oils, exploiting the advantages of a ... [more ▼]

The present research is based on the development of an effective, environmentally-friendly and low-cost method for investigation of minor components in vegetable oils, exploiting the advantages of a miniaturized solid-phase extraction (SPE) and the potential of flow modulation (FM) comprehensive two-dimensional gas chromatography (GC×GC), coupled to a mass spectrometer (MS) and a flame ionization detector (FID). The initial sample preparation step was carried out using a miniaturized approach characterized by a SPE process in a Pasteur pipette. Then, the isolated fraction was injected into an FM GC×GC system. Tentative identification was carried out by means of MS spectral information, while quantification was carried out by using the FID data. Four different vegetable oil samples were analyzed using the proposed method, namely an extra virgin olive oil (EVO), a hazelnut oil (HO), a borage oil, and an EVO/HO mixture. © 2017 Elsevier B.V. [less ▲]

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