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This article critically reviews analytical method validation and quality control applied to the environmental chemistry field. The review focuses on the determination of organic micropollutants (OMPs), specifically emerging contaminants and pesticides, in the aquatic environment. The analytical technique considered is (gas and liquid) chromatography coupled to mass spectrometry (MS), including high-resolution MS for wide-scope screening purposes. An analysis of current research practices outlined in the literature has been performed, and key issues and analytical challenges are identified and critically discussed. It is worth emphasizing the lack of specific guidelines applied to environmental analytical chemistry and the minimal regulation of OMPs in waters, which greatly affect method development and performance, requirements for method validation, and the subsequent application to samples. Finally, a proposal is made for method validation and data reporting, which can be understood as starting points for further discussion with specialists in environmental analytical chemistry.
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Plants compete with their neighbors about the limited resources available to them. Plants under induced stress resulting from competition may alter their metabolome to increase their resilience or enhance their defense mechanisms. In the present study, rye (Secale cereale) plants were cocultivated with different densities (3, 12, and 18 plants per pot) of Austrian pea (Pisum sativum subsp. arvense), hairy vetch (Vicia villosa), and Alexandrian clover (Trifolium alexandrinum L.) to elucidate the changes in the rye metabolome in response to the different levels of competition. Global metabolic profiling by liquid chromatography triple quadrupole tandem mass spectrometry (LC-QqQ-MS), liquid chromatography quadrupole time-of-flight mass spectrometry (LC-QTOF-MS), and gas chromatography time-of-flight mass spectrometry (GC-TOF-MS) was performed on rye plants, and the acquired data were analyzed using uni- and multivariate statistics. Targeted analysis showed that a high level of competition reduced the concentration of aglycone benzoxazinoids (BXs) and increased glycoside BXs in rye roots. Untargeted metabolomics analysis indicated an increase in the rye root content of the allelopathic compounds 4-hydroxybenzoic acid and uracil in response to competition. Untargeted analysis of rye shoots revealed that the plant competition increased the d-pyroglutamic acid, which is an elicitor of reactive oxygen species (ROS). Our results have enhanced the knowledge of the biochemical response of plant species to cocultivation.
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Secale , Espectrometría de Masas en Tándem , Cromatografía Liquida/métodos , Cromatografía de Gases y Espectrometría de Masas , Metaboloma , Metabolómica/métodos , Secale/química , Espectrometría de Masas en Tándem/métodosRESUMEN
In this review, recent advances and applications using multi-way calibration protocols based on the processing of multi-dimensional chromatographic data are discussed. We first describe the various modes in which multi-way chromatographic data sets can be generated, including some important characteristics that should be taken into account for the selection of an adequate data processing model. We then discuss the different manners in which the collected instrumental data can be arranged, and the most usually applied models and algorithms for the decomposition of the data arrays. The latter activity leads to the estimation of surrogate variables (scores), useful for analyte quantitation in the presence of uncalibrated interferences, achieving the second-order advantage. Recent experimental reports based on multi-way liquid and gas chromatographic data are then reviewed. Finally, analytical figures of merit that should always accompany quantitative calibration reports are described.
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BACKGROUND: Lifetime exposure to environmental (neuro) toxicants may contribute to the pathogenesis of Alzheimer's Disease (AD). Since many contaminants do not cross the blood-brain barrier, brain tissue alone cannot serve to assess the spectrum of environmental exposures. METHODS: We used liquid and gas chromatography tandem mass spectrometry to monitor, in postmortem liver and adipose tissues of AD patients and age-matched controls, the occurrence and concentrations of 11 environmental contaminants. RESULTS: Seven toxicants were detected at 100% frequency: p,p'-DDE, dieldrin, triclosan, methylparaben, bisphenol A, fipronil and tetrabromobisphenol A (TBBPA). Intra-individual, tissuedependent differences were detected for triclosan, methylparaben, fipronil and TBBPA. High concentrations of p,p'-DDE and dieldrin were observed in adipose tissue when compared to liver values for both AD cases and controls. CONCLUSION: This study provides vital data on organ-specific human body burdens to select analytes and demonstrate the feasibility of analyzing small sample quantities for toxicants suspected to constitute AD risk factors.
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Tejido Adiposo/química , Enfermedad de Alzheimer , Contaminantes Ambientales/análisis , Hígado/química , Exposición a Riesgos Ambientales/efectos adversos , HumanosRESUMEN
High amounts of cholesterol have been definitely associated with the pathogenesis of several diseases, including metabolic and neurodegenerative disorders, cardiovascular diseases, and cancer. In all these pathologies the exacerbation of pro-oxidant and inflammatory responses is a consistent feature. In this scenario, species derived from enzymatic and non-enzymatic cholesterol oxidation, namely oxysterols, are strongly suspected to play a primary role. The consideration of these bioactive lipids is therefore helpful in investigating pathological mechanisms and may also acquire clinical value for the diagnosis and treatment of diseases. For this purpose and considering that a great number of oxysterols may be present together in the body, the employment of lipidomics technology certainly represents a powerful strategy for the simultaneous detection and characterization of these compounds in biological specimens. In this review, we will discuss the applicability of the lipidomics approach in the study of the association between oxysterols and diseases.
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Enfermedades Cardiovasculares/metabolismo , Colesterol/análisis , Lipidómica/métodos , Enfermedades Metabólicas/metabolismo , Neoplasias/metabolismo , Enfermedades del Sistema Nervioso/metabolismo , Oxiesteroles/análisis , Animales , Biomarcadores/metabolismo , Enfermedades Cardiovasculares/diagnóstico , Enfermedades Cardiovasculares/fisiopatología , Colesterol/química , Colesterol/metabolismo , Cromatografía Liquida , Cromatografía de Gases y Espectrometría de Masas , Humanos , Inflamación , Metabolismo de los Lípidos , Lipidómica/instrumentación , Enfermedades Metabólicas/diagnóstico , Enfermedades Metabólicas/fisiopatología , Neoplasias/diagnóstico , Neoplasias/fisiopatología , Enfermedades del Sistema Nervioso/diagnóstico , Enfermedades del Sistema Nervioso/fisiopatología , Estrés Oxidativo , Oxiesteroles/química , Oxiesteroles/metabolismo , Especies Reactivas de Oxígeno/análisis , Especies Reactivas de Oxígeno/química , Especies Reactivas de Oxígeno/metabolismoRESUMEN
Main goals of the present work were to develop authentication models based on liquid and gas chromatographic fingerprinting of triacylglycerols (TAGs) from palm oil of different geographical origins in order to compare them. For this purpose, a set of palm oil samples were collected from different continents: South eastern Asia, Africa and South America. For the analysis of the information in these fingerprint profiles, a pattern recognition technique such as partial least square discriminant analysis (PLS-DA) was applied to discriminate the geographical origin of these oils, at continent level. The liquid chromatography, coupled to a charged aerosol detector, (HPLC-CAD) TAGs separation was optimized in terms of mobile phase composition and by means of a solid silica core column. The gas chromatographic method with a mass spectrometer was applied under high temperature (HTGC-MS) in order to analyze the intact TAGs. Satisfactory chromatographic resolution within a short total analysis time was achieved with both chromatographic approaches and without any prior sample treatment. The rates of successful in prediction of the geographical origin of the 85 samples varied between 70% and 100%.
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Aceites de Plantas , Triglicéridos/aislamiento & purificación , África , Asia Sudoriental , Cromatografía Líquida de Alta Presión , Análisis Discriminante , Cromatografía de Gases y Espectrometría de Masas , Análisis de los Mínimos Cuadrados , Aceite de Palma , Aceites de Plantas/química , Aceites de Plantas/clasificación , América del SurRESUMEN
Analysis of pesticides and their metabolites in food and water matrices continues to be an active research area closely related to food safety and environmental issues. This review discusses the most widely applied mass spectrometric (MS) approaches to pesticide residues analysis over the last few years. The main techniques for sample preparation remain solvent extraction and solid-phase extraction. The QuEChERS (Quick, Easy, Cheap, Effective, Rugged, Safe) approach is being increasingly used for the development of multi-class pesticide residues methods in various sample matrices. MS detectors-triple quadrupole (QqQ), ion-trap (IT), quadrupole linear ion trap (QqLIT), time-of-flight (TOF), and quadrupole time-of-flight (QqTOF)-have been established as powerful analytical tools sharing a primary role in the detection/quantification and/or identification/confirmation of pesticides and their metabolites. Recent developments in analytical instrumentation have enabled coupling of ultra-performance liquid chromatography (UPLC) and fast gas chromatography (GC) with MS detectors, and faster analysis for a greater number of pesticides. The newly developed "ambient-ionization" MS techniques (e.g., desorption electrospray ionization, DESI, and direct analysis in real time, DART) hyphenated with high-resolution MS platforms without liquid chromatography separation, and sometimes with minimum pre-treatment, have shown potential for pesticide residue screening. The recently introduced Orbitrap mass spectrometers can provide high resolving power and mass accuracy, to tackle complex analytical problems involved in pesticide residue analysis.