Gas chromatography-tandem mass spectrometry with atmospheric pressure chemical ionization for fluorotelomer alcohols and perfluorinated sulfonamides determination

Ionization and in source-fragmentation behavior of four fluorotelomer alcohols (FTOH) (4:2 FTOH, 6:2FTOH, 8:2 FTOH and 10:2 FTOH) and four N-alkyl fluorooctane sulfonamides/-ethanols (N-MeFOSA, N-EtFOSA, N-MeFOSE and N-EtFOSE) by APCI has been studied and compared with the traditionally usedEI and CI. Protonated molecule was the base peak of the APCI spectrum in all cases giving the possibilityof selecting it as a precursor ion for MS/MS experiments. Following, CID fragmentation showed commonproduct ions for all FOSAs/FOSEs (C4F7and C3F5). Nevertheless, the different functionality gave charac-teristic pattern fragmentations. For instance, FTOHs mainly loss H2O + HF, FOSAs showed the losses ofSO2and HF while FOSEs showed the losses of H2O and SO2. Linearity, repeatability and LODs have beenstudied obtaining instrumental LODs between 1 and 5 fg. Finally, application to river water and influentand effluent waste water samples has been carried out in order to investigate the improvements in detec-tion capabilities of this new source in comparison with the traditionally used EI/CI sources. Matrix effectsin APCI have been evaluated in terms of signal enhancement/suppression when comparing standardsin solvent and matrix. No matrix effects were observed and concentrations found in samples were inthe range of 1-100 pg L−1far below the LODs achieved with methods previously reported. Unknownrelated perfluoroalkyl substances, as methyl-sulfone and methyl-sulfoxide analogues for FTOHs, werealso discovered and tentatively identified

Estudio de la Influencia de la alineación semántica en la resolución de problemas verbales de estequiometría

Con este trabajo se quiere analizar el efecto de la denominada alienación semántica en la resolución de problemas verbales de estequiometría. Además, se pretende estudiar cómo la formación académica puede intervenir en este efecto. Para ello, se administraron al azar entre 160 estudiantes de educación secundaria de diversos niveles académicos (desde 9º grado hasta 12º grado) dos problemas de estequiometría con entidades discretas (moléculas). En uno de los problemas aparecían fracciones, y en el otro problema porcentajes. De las puntuaciones obtenidas en la resolución de los problemas y del ANOVA efectuado, se puede concluir que: a) los estudiantes consiguen un éxito significativamente mayor en el problema con fracciones, confirmándose el fenómeno de la alineación semántica; b) un mayor nivel académico mejora de forma significativa el rendimiento en la resolución de ambos problemas; y c) solo en los niveles académicos bajos (9º y 10 grado) hay diferencias significativas entre la puntuación del problema con fracciones y del problema con porcentajes. The aim of this work is to analyze the effect of the so-called semantic alignment on stoichiometric word problem solving. In addition, the aim is to study how academic training can have an impact on this effect. For this purpose, two stoichiometry problems with discrete entities (molecules) were randomly administered to 160 secondary school students in different grade levels (from 9th grade to 12th grade). Fractions appeared in one of the problems and percentages in the other. From the scores obtained in solving the problems and from the ANOVA performed, it can be concluded that: a) students achieve significantly greater success in the problem with fractions, confirming the phenomenon of semantic alignment; b) a higher grade level significantly improves performance in solving both problems; and c) only in low grade levels (9th and 10th grade) there are significant differences between the score of the problem with fractions and the problem with percentage

Screening of pesticides and polycyclic aromatic hydrocarbons in feeds and fish tissues by gas chromatography coupled to high-resolution mass spectrometry using atmospheric pressure chemical ionization

This paper reports a wide-scope screening for detection and identification of pesticides and polycyclic aromatic hydrocarbons (PAHs) in feeds and fish tissues. QuEChERS sample treatment was applied, using freezing as an additional cleanup. Analysis was carried out by gas chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry with atmospheric pressure chemical ionization (GC-(APCI) QTOF MS). The qualitative validation was performed for over 133 representative pesticides and 24 PAHs at 0.01 and 0.05 mg/kg. Subsequent application of the screening method to aquaculture samples made it possible to detect several compounds from the target list, such as chlorpyrifos-methyl, pirimiphos-methyl, and ethoxyquin, among others. Light PAHs (≤4 rings) were found in both animal and vegetable samples. The reliable identification of the compounds was supported by accurate mass measurements and the presence of at least two representative m/z ions in the spectrum together with the retention time of the peak, in agreement with the reference standard. Additionally, the search was widened to include other pesticides for which standards were not available, thanks to the expected presence of the protonated molecule and/or molecular ion in the APCI spectra. This could allow the detection and tentative identification of other pesticides different from those included in the validated target list. © 2014 American Chemical Society.This work has been (partly) funded under the EU Seventh Framework Programme by ARRAINA Project 288925: Advanced Research Initiatives for Nutrition and Aquaculture. The views expressed in this work are the sole responsibility of the authors and do not necessarily reflect the views of the European Commission. This work has been developed within the framework of the Research Unit of Marine Ecotoxicology (IATS (CSIC)-IUPA (UJI)). We also acknowledge the financial support of Generalitat Valenciana (research group of excellence PROMETEO/2009/054; ISIC 2012/016).Peer Reviewe

A comprehensive study on diesel oil bioremediation under microcosm conditions using a combined microbiological, enzymatic, mass spectrometry, and metabarcoding approach

This study aims at the application of a marine fungal consortium (Aspergillus sclerotiorum CRM 348 and Cryptococcus laurentii CRM 707) for the bioremediation of diesel oil-contaminated soil under microcosm conditions. The impact of biostimulation (BS) and/or bioaugmentation (BA) treatments on diesel-oil biodegradation, soil quality, and the structure of the microbial community were studied. The use of the fungal consortium together with nutrients (BA/BS) resulted in a TPH (Total Petroleum Hydrocarbon) degradation 42% higher than that obtained by natural attenuation (NA) within 120 days. For the same period, a 72 to 92% removal of short-chain alkanes (C12 to C19) was obtained by BA/BS, while only 3 to 65% removal was achieved by NA. BA/BS also showed high degradation efficiency of long-chain alkanes (C20 to C24) at 120 days, reaching 90 and 92% of degradation of icosane and heneicosane, respectively. In contrast, an increase in the levels of cyclosiloxanes (characterized as bacterial bioemulsifiers and biosurfactants) was observed in the soil treated by the consortium. Conversely, the NA presented a maximum of 37% of degradation of these alkane fractions. The 5-ringed PAH benzo(a)pyrene, was removed significantly better with the BA/BS treatment than with the NA (48 vs. 38 % of biodegradation, respectively). Metabarcoding analysis revealed that BA/BS caused a decrease in the soil microbial diversity with a concomitant increase in the abundance of specific microbial groups, including hydrocarbon-degrading (bacteria and fungi) and also an enhancement in soil microbial activity. Our results highlight the great potential of this consortium for soil treatment after diesel spills, as well as the relevance of the massive sequencing, enzymatic, microbiological and GC-HRMS analyses for a better understanding of diesel bioremediation.This research was financially supported by the Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP) (grant #2016/07957-7) and by Conselho Nacional de Desenvolvimento Tecnológico (CNPq) (grant #407986/2018-6).Peer reviewe

Uso de técnicas avanzadas cromatografía de gases/espectrometría de masas con analizadores de triple cuadrupolo y tiempo de vuelo en análisis medioambiental y biológico

En la presente Tesis se pretende avanzar en el conocimiento del potencial que representa el acoplamiento cromatografía de gases-espectrometría de masas con analizadores de triple cuadrupolo y tiempo de vuelo como herramienta de avanzada en el análisis medioambiental y biológico. El trabajo se organiza en tres grandes bloques. En primer lugar, se investiga el uso de la técnica GC-MS/MS con analizador de triple cuadrupolo para el desarrollo de metodología analítica multirresidual que permita la cuantificación y confirmación de contaminantes orgánicos en aguas y en muestras de tejido adiposo mamario. En segundo lugar, se explora el potencial del acoplamiento GC-TOF MS para el desarrollo de métodos avanzados y rápidos de screening para un amplio rango de contaminantes. El trabajo se centra principalmente en aspectos cualitativos y de elucidación estructural, campos en donde la gran cantidad de información aportada por GC-TOF MS es fundamental, al permitir la correcta identificación de las especies detectadas. Por último, se combinan las técnicas GC-MS/MS y LC-MS/MS con triple cuadrupolo y tiempo de vuelo en estudios ambientales y toxicológicosIn this Thesis the potential of coupling gas chromatography-mass spectrometry with triple quadrupole and time-of-flight analyzers is investigated as an advanced analytical technique in environmental and biological analysis

Non-target screening of organic contaminants in marine salts by gas chromatography coupled to high-resolution time-of-flight mass spectrometry

23 p., 1 figure, 2 tables and bibliographyGas chromatography coupled to time-of-flight mass spectrometry (GC-TOF MS) has been applied to characterize the organic pollution pattern of marine salt samples collected in saltworks from the Spanish Mediterranean coast. After dissolving the samples in water, a solid-phase extraction was applied reaching with a 250- preconcentration factor. The screening methodology allowed the detection of sample components without any kind of pre-selection of target pollutants. The identity of components detected was established by accurate mass measurements and comparison of experimental full-acquisition spectra with theoretical MS libraries. Several organic pollutants were identified in the samples, like plasticizers -potentially toxic to humans and fragrances -included within the group of pharmaceuticals and personal care products-, among others. Our results indicate that these contaminants can be found in the marine salt after the crystallization process. GC-TOF MS is a powerful technique for wide-scope screening of (semi)volatile, low-polar organic contaminants, able to investigate the presence of a large number of compounds. Searching of contaminants is not restricted to a target list of compounds. Therefore, unexpected contaminants can be discovered in an efficient way, with better sensitivity and selectivity than other conventional analytical techniques, and making use of the powerful qualitative information provided by full-spectrum acquisition at accurate mass.This research was supported by the Spanish Ministry for Education and Science (Projects CGL2005-02306/BOS and CTQ 2009-12347). The authors acknowledge the financial support of the Generalitat Valenciana, as research group of excellence PROMETEO/2009/054. The authors are also grateful to the Serveis Centrals d’Instrumentació Científica (SCIC) of the University Jaume I for the use the GC-TOF MS instrument

Characterization of the organic contamination pattern of a hyper-saline ecosystem by rapid screening using gas chromatography coupled to high-resolution time-of-flight mass spectrometry

In this paper, gas chromatography coupled to high-resolution time-of-flight mass spectrometry (GC-TOF MS) has been applied to evaluate organic pollution in a hyper-saline aquatic environment. Firstly, a target screening was made for a list of 150 GC-amenable organic micro-contaminants, including PAHs, octyl/nonyl phenols, PCBs, PBDEs, and a notable number of pesticides, such us insecticides (organochlorines, organophosphorus, carbamates and pyrethroids), herbicides (triazines and chloroacetanilides), fungicides and several transformation products. This methodology was applied to brine samples, with a salt content from 112. g/L to saturation, and to samples from Artemia populations (crustacean Anostraca) collected during 1. year from three sampling stations in saltworks bodies sited in the Ebro river delta. Around 50 target contaminants, belong to chemical families included in the list of priority substances within the framework on European water policy. Additionally, a non-target analysis was performed in both types of samples with the objective of investigating the presence of other non-selected organic compounds taking advantage of the potential of GC-TOF MS (high sensitivity in full-spectrum acquisition mode, accurate mass measurements) for searching unknowns. Organophosphorus pesticides were the contaminants more frequently detected in brine samples. Other compounds usually present in urban and industrial wastewaters, like caffeine, methylparaben, butylated-hydroxytoluene and N-butylbenzenesulfonamide were also detected in brines. The herbicide simazine and the insecticide chlorpyrifos were among the contaminants detected in Artemia samples. Results of this work reveal a potential threat to vulnerable populations inhabiting the hyper-saline ecosystem. The valuable contribution of GC-TOF MS in environmental analysis, allowing the rapid screening of a large number of organic contaminants, is also demonstrated in this paper. © 2012 Elsevier B.V.This research was supported by the Spanish Ministry for Education and Science project (CGL2005-02306/BOS) “Biodiversidad de Artemia (Branchiopoda, Anostraca) en el Mediterráneo occidental. Presencia de A. franciscana como especie invasora. Implicaciones ecológicas y de interés en acuicultura”. The authors addressed in IUPA acknowledge the financial support of Generalitat Valenciana, as research group of excellence PROMETEO/2009/054.Peer Reviewe