Searching for anthropogenic contaminants in human breast adipose tissues using gas chromatography-time-of-flight mass spectrometry

The potential of GC-TOF MS for screening anthropogenic organic contaminants in human breast adipose tissues has been investigated. Initially a target screening was performed for a list of 125 compounds which included persistent halogen pollutants (OC pesticides, PCBs, PBDEs), PAHs, alkylphenols, and a notable number of pesticides from the different fungicide, herbicide and insecticide families. Searching for target pollutants was done by evaluating the presence of up to five representative ions for every analyte, all measured at accurate mass (20 mDa mass window). The experimental ion abundance ratios were then compared to those of reference standards for confirmation. Sample treatment consisted of an extraction with hexane and subsequent normal-phase HPLC or SPE clean-up. The fat-free LC fractions were then investigated by GC-TOF MS. Full-spectral acquisition and accurate mass data generated by GC-TOF MS also allowed the investigation of non-target compounds using appropriate processing software to manage MS data. Identification was initially based on library fit using commercial nominal mass libraries. This was followed by comparing the experimental accurate masses of the most relevant ions with the theoretical exact masses with calculations made using the elemental composition calculator included in the software. The application of both target and non-target approaches to around 40 real samples allowed the detection and confirmation of several target pollutants including p,p’- DDE, HCB, and some PCBs and PAHs. Several non-target compounds that could be considered anthropogenic pollutants were also detected. These included 3,5-di-tert-butyl-4-hydroxy-toluene (BHT) and its metabolite 3,5-di-tert-butyl-4-hydroxybenzaldehyde (BHT-CHO), dibenzylamine, n-butyl benzenesulfonamide, some naphthalene-related compounds and several PCBs isomers not 2included in the target list. As some of the compounds detected are xenoestrogens the methodology developed in this paper could be useful in human breast cancer researc

Determination of PBDEs in human breast adipose tissues by gas chromatography coupled to triple quadrupole mass spectrometry

The potential of gas chromatography / tandem mass spectrometry with triple quadrupole analyzer for determination of 12 polybrominated diphenyl ethers in human breast tissues has been investigated. After extraction with hexane, two purification procedures -automated normal-phase HPLC and solid phase extraction – were assayed. Both electron impact ionization, in selected reaction monitoring mode, and negative chemical ionization, in selected ion recording mode, were tested for the optimum determination of analytes. Isotopically labelled standards were added before extraction as surrogates: [13C] BDE47, [13C] BDE99 and [13C] BDE153 for EI, and p,p’-DDE-D8 for NCI. The method was validated in terms of accuracy, precision, limits of detection and limits of quantification, using human breast tissue spiked at three levels in the range 1-50 ng/g (5-250 ng/g for BDE 209). The analytical approach using SPE clean-up followed by GC-MS (NCI) led to lower detection limits (0.006-2 ng/g) and allowed the determination of the most problematic congener, BDE 209, whose poor sensitivity made difficult its determination at low residue levels. Special attention was given to the confirmation of the compounds detected in samples in order to avoid reporting false positives. Two MS/MS transitions or three m/z ions were selected for each analyte when using EI or NCI modes, respectively. In both cases, the transition/ion intensity ratio was used as confirmation parameter. The developed methodology was applied to the analysis of real human samples. Several BDEs (BDEs congeners 47, 100, 99, 154, 153 183 and 209) were detected in the range of 0.08-0.23 ng/

El efecto Pigmalión, autoestima y rendimiento escolar

XVIII Jornades de Foment de la Investigació de la Facultat de Ciències Humanes i Socials (Any 2013)Con la presente investigación pretendemos descubrir la influencia de las emociones positivas y negativas a través de los procesos motivacionales en la realización de las tareas escolares. Para ello hemos hecho un estudio de caso, centrando nuestra planificación en una niña de 10 años. La metodología utilizada durante el proceso ha sido un pre y post-test para medir la autoestima de la alumna y tomando como punto de referencia los resultados académicos, para poder mejorar su baja autoestima hemos desarrollado un programa de intervención basada en el refuerzo positivo. Tras el análisis de cada uno de los aspectos mencionados hemos podido concluir que el rendimiento académico va estrechamente ligado a las emociones, a la autoestima y por tanto al efecto Pigmalión

Comparison of Simple and Rapid Extraction Procedures for the Determination of Pesticide Residues in Fruit Juices by Fast Gas Chromatography–Mass Spectrometry

Three sample treatment methods, based on QuEChERS, solid-phase extraction (SPE) and solid-phase microextraction (SPME), were compared and evaluated in order to obtain the best conditions to determine pesticide residues in fruit juice by fast gas chromatography–mass spectrometry (single quadrupole GC-MS). Analysis were performed under selected ion monitoring, acquiring the three most abundant and/or specific ions for each analyte and using their relative intensity ratios as a confirmatory parameter. The 3 methodologies (QuEChERS, SPE and SPME) were validated taking 15 selected pesticides as model compounds, using commercial apple juice. QuEChERS procedure was based on the AOAC Official Method 2007.01, using acetonitrile (containing 1 % acetic acid) as extraction solvent and primary–secondary amine during the dispersive solid-phase extraction. Oasis hydrophilic–lipophilic balance cartridges were used for SPE, and polyacrylate fibers were used for direct immersion SPME procedure. Three isotopically labeled standards were added to the samples before extraction and used as surrogate standards. Validation parameters as recoveries, limits of detection, and limits of quantification (LOQ), as well as matrix effects and sample throughput, were obtained and compared for the three extraction procedures. QuEChERS was considered faster and led to the best quantitative results. In this way, validation was extended to up to 56 pesticides by applying QuEChERS in multi-fruit juice samples, obtaining LOQs ranging from 2 to 20 μg/L for most compounds. Accuracy and precision were evaluated by means of recovery experiments at two concentration levels (10 and 100 μg/L), obtaining recoveries between 70 and 120 % in most cases and relative standard deviations below 15 %. Finally, the QuEChERS method was applied to the analysis of commercial juices, including mango–apple, pineapple, grapefruit and orange

Evaluation of direct sample injection as a fast, no-sample handling, approach for the LC-MS/MS monitoring of pharmaceuticals in different water matrices

The determination of drug residues in water, particularly in environmental water, is a hot topic due to the usual presence of these emerging contaminants in the aquatic environment and their potential negative impact on water quality. The most widely approach applied at present for their determination is the use of a solid phase extraction (SPE) step followed by the LC-MS/MS measurement. This is due to the theoretical need to preconcentrate the analytes and to produce “clean” sample extracts leading to less inferences in subsequent analysis. However, in LC-MS/MS based methods, the main interferences are not “visible” and are mostly due to matrix effects, which in fact are produced by unknown compounds that co-elute with the analytes and therefore not easily removed by SPE. As an alternative, an increasing trend is observed towards the use of direct injection (DI) of the samples, which is nowadays possible thank to the notable improvement in sensitivity of modern LCMS/MS instrumentation. In this work, both approaches, SPE and DI, have been evaluated for the determination of 16 pharmaceuticals in three different types of water: groundwater, surface water and effluent wastewater. The study has been performed by using pharmaceutical reference standards and their corresponding isotope-labelled internal standards (ILIS) for efficient matrix effects correction. Both methodologies have been compared in terms of matrix effects, sensitivity, and suitability for the analysis of real-world water samples. Our data show that DI is an efficient alternative to SPE, with satisfactory analyte recoveries for most pharmaceuticals, matrix effects even lower than in SPE, and sufficient sensitivity for most of applications. In addition, the absence of sample treatment minimizes potential errors associated with this step, and there is a notable saving in the analysis time and costs. The analysis of Quality Control (QC) samples included in different sample batch sequences has been used to support the feasibility of using DI in this type of analysis.Funding for open access charge: CRUE-Universitat Jaume

Rapid and sensitive analytical method for the determination of amoxicillin and related compounds in water meeting the requirements of the European union watch list

The presence of antibiotics in the aquatic environment is becoming one of the main research focus of scientists and policy makers. Proof of that is the inclusion of four antibiotics, amongst which is amoxicillin, in the EU Watch List (WL) (Decision 2020/1161/EU)) of substances for water monitoring. The accurate quantification of amoxicillin in water at the sub-ppb levels required by the WL is troublesome due to its physicochemical properties. In this work, the analytical challenges related to the determination of amoxicillin, and six related penicillins (ampicillin, cloxacillin, dicloxacillin, penicillin G, penicillin V and oxacillin), have been carefully addressed, including sample treatment, sample stability, chromatographic analysis and mass spectrometric detection by triple quadrupole. Given the low recoveries obtained using different solid-phase extraction cartridges, we applied the direct injection of water samples using a reversed-phase chromatographic column that allowed working with 100% aqueous mobile phase. Matrix effects were evaluated and corrected using the isotopically labelled internal standard or correction factors based on signal suppression observed in the analysis of spiked samples. The methodology developed was satisfactorily validated at 50 and 500 ng L − 1 for the seven penicillins studied, and it was applied to different types of water matrices, revealing the presence of ampicillin in one surface water sample and cloxacillin in three effluent wastewater samples.Funding for open access charge: CRUE-Universitat Jaume

Analytical key issues and challenges in the LC-MS/MS determination of antibiotics in wastewater

The research on antibiotics occurrence in the aquatic environment has become a hot topic in the last years due to their potential negative effects, associated to possible bacterial antibiotic-resistance, after continuous exposure to these compounds. Most of antibiotic residues are not completely removed in the wastewater treatment plants (WWTPs) and end up in the aquatic environment through treated wastewater (WW). The development of reliable analytical methodologies for the determination of antibiotics in influent (IWW) and effluent wastewater (EWW) is needed with different purposes, among others: monitoring their occurrence in the aquatic environment, performing environmental risk assessment, estimating removal efficiencies of WWTPs, or estimating the consumption of these compounds. In this paper, we perform an in-depth investigation on analytical key issues that pose difficulties in the determination of antibiotics in complex matrices, such as WW, and we identify challenges to be properly addressed for successful analysis. The analytical technique selected was liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS), as it is the most powerful and widely applied at present for antibiotic residues determination. The mass spectrometric behavior of 18 selected antibiotics, the chromatographic performance, ion ratio variations associated to the sample matrix when using different precursor ions or protomers, and the macrolides adsorption to glass vial, were some of the issues studied in this work. On the basis of the detailed study performed, an analytical LC-MS/MS method based on sample direct injection has been developed for quantification of 18 antibiotics in IWW and EWW, allowing their determination at low ng L−1 levels.Funding for open access charge: CRUE-Universitat Jaume IDavid Fabregat-Safont acknowledges Ministerio de Universidades in Spain for his Margarita Salas postdoctoral grant (Ref. MGS/2021/15). Authors acknowledge financial support from General Directorate of Water (Conselleria de Agricultura, Desarrollo Rural, Emergencia Climática y Transición Ecológica) and Generalitat Valenciana (research group of excellence PROMETEO 2019/040). Authors also acknowledge to FACSA (Castelló, Spain) for the wastewater sample collection and the Ayuntamiento of Castelló for the authorization to collect wastewater samples from the WWTP of Castelló. Authors are very grateful to Alberto Celma for his comments on fluoroquinolones protomers evaluation

La aplicación de los sistemas complejos al estudio de la variación lingüística: El caso de la pérdida de la F- inicial latina.

Este proyecto adapta el modelo computacional de Pardo-Gordó (2020º “Cultural Hitchhicking” para indagar en las aplicaciones del marco teórico de los sistemas complejos a la variación lingüística. La investigación simula distintos aspectos de la pérdida de la F- inicial latina relevantes en la teoría sustratística de Menéndez Pidal y evalúa hasta qué punto este tipo de modelos se adaptan a la realidad lingüística y pueden ser útiles para su investigación. <br /

The role of GC-MS/MS with triple quadrupole in pesticide residue analysis in food and the environment

Gas chromatography coupled to tandem mass spectrometry (GC-MS/MS) using a triple quadrupole (QqQ) analyzer has in the last few years become a powerful technique for the determination of pesticide residues due to its robustness, and excellent sensitivity and selectivity. This review gives an overview of currently published applications of GC-MS/MS with a QqQ analyzer for pesticide residue analysis of different food and environmental sample matrices. This technique allows the reliable quantification and identification of low pesticide concentrations for non-polar (semi) volatile compounds belonging to different chemical families. It has allowed a notable improvement of methods performance in comparison with the traditional GC methods with single stage quadrupole MS

Application of gas chromatography time-of-flight mass spectrometry for target and non-target analysis of pesticide residues in fruits and vegetables

In this work, the capability of gas chromatography coupled to time-of-flight mass spectrometry (GC–TOF MS) for quantitative analysis of pesticide residues has been evaluated. A multiclass method for rapid screening of pesticides (insecticides, acaricides, herbicides and fungicides) in fruit and vegetable matrices has been developed and validated, including detection, identification and quantification of the analytes. To this aim, several food matrices were selected: high water content (apples, tomatoes and carrots), high acid content (oranges) and high oil content (olives) samples. The well known QuEChERS procedure was applied for extraction of pesticides, and matrix-matched calibration using relative responses versus internal standard was used for quantification. The sample extracts were analyzed by GC–TOF MS. Up to five ions using narrow window (0.02 Da)-extracted ion chromatograms at the expected retention time were monitored using a target processing method. The most abundant ion was used for quantification while the remaining ones were used for confirmation of the analyte identity. Method validation was carried out for 55 analytes in the five sample matrices tested at three concentrations (0.01, 0.05 and 0.5 mg/kg). Most recoveries were between 70% and 120% with relative standard deviations (RSDs) lower than 20% at 0.05 and 0.5 mg/kg. At 0.01 mg/kg, roughly half of the pesticides could be satisfactorily validated due to sensitivity limitations of GC–TOF MS, which probably affected the ion ratios used for confirmation of identity. In the case of olive samples, results were not satisfactory due to the high complexity of the matrix. An advantage of TOF MS is the possibility to perform a non-target investigation in the samples by application of a deconvolution software, without any additional injection being required. Accurate-mass full-spectrum acquisition in TOF MS provides useful information for analytes identification, and has made feasible in this work the discovery of non-target imazalil, fluoranthene and pyrene in some of the samples analyzed