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1.
J Agric Food Chem ; 71(42): 15842-15854, 2023 Oct 25.
Artículo en Inglés | MEDLINE | ID: mdl-37846851

RESUMEN

A polyhydroxy methacrylate-based stationary reversed phase was used for the determination of coformulants in 20 plant protection products (PPPs). These samples were analyzed by liquid chromatography coupled to Q-Orbitrap high-resolution mass spectrometry (LC-Q-Orbitrap-HRMS) in full-scan MS and data-dependent acquisition (ddMS2) modes. A total of 92 coformulants were tentatively identified in these formulations by nontargeted and unknown analyses. Twelve out of them were quantified by analytical standards. The most concentrated coformulant was the anionic surfactant dodecylbenzenesulfonic acid, whose highest content was obtained in the Score 25 sample (6.87%, w/v). Furthermore, triethylene glycol monomethyl ether, 4-s-butyl-2,6-di-tert-butylphenol, 1-ethyl-2-pyrrolidone, sorbitan monostearate, 2,6-dimethylaniline, palmitamide, and N-lauryldiethanolamine were quantified for the first time in these products. Hence, the polyhydroxy methacrylate-based stationary phase increased the identification of new coformulants in PPPs, being complementary to conventional C18. This strategy could be applied in future studies to estimate potential coformulant residues from PPPs applied to crops.


Asunto(s)
Cromatografía Liquida , Cromatografía Liquida/métodos , Espectrometría de Masas , Cromatografía Líquida de Alta Presión/métodos
2.
Front Hum Neurosci ; 16: 942551, 2022.
Artículo en Inglés | MEDLINE | ID: mdl-35911598

RESUMEN

Many individuals with disabling conditions have difficulty with gait and balance control that may result in a fall. Exoskeletons are becoming an increasingly popular technology to aid in walking. Despite being a significant aid in increasing mobility, little attention has been paid to exoskeleton features to mitigate falls. To develop improved exoskeleton stability, quantitative information regarding how a user reacts to postural challenges while wearing the exoskeleton is needed. Assessing the unique responses of individuals to postural perturbations while wearing an exoskeleton provides critical information necessary to effectively accommodate a variety of individual response patterns. This report provides kinematic and neuromuscular data obtained from seven healthy, college-aged individuals during posterior support surface translations with and without wearing a lower limb exoskeleton. A 2-min, static baseline standing trial was also obtained. Outcome measures included a variety of 0 dimensional (OD) measures such as center of pressure (COP) RMS, peak amplitude, velocities, pathlength, and electromyographic (EMG) RMS, and peak amplitudes. These measures were obtained during epochs associated with the response to the perturbations: baseline, response, and recovery. T-tests were used to explore potential statistical differences between the exoskeleton and no exoskeleton conditions. Time series waveforms (1D) of the COP and EMG data were also analyzed. Statistical parametric mapping (SPM) was used to evaluate the 1D COP and EMG waveforms obtained during the epochs with and without wearing the exoskeleton. The results indicated that during quiet stance, COP velocity was increased while wearing the exoskeleton, but the magnitude of sway was unchanged. The OD COP measures revealed that wearing the exoskeleton significantly reduced the sway magnitude and velocity in response to the perturbations. There were no systematic effects of wearing the exoskeleton on EMG. SPM analysis revealed that there was a range of individual responses; both behaviorally (COP) and among neuromuscular activation patterns (EMG). Using both the OD and 1D measures provided a more comprehensive representation of how wearing the exoskeleton impacts the responses to posterior perturbations. This study supports a growing body of evidence that exoskeletons must be personalized to meet the specific capabilities and needs of each individual end-user.

3.
J Agric Food Chem ; 70(23): 7302-7313, 2022 Jun 15.
Artículo en Inglés | MEDLINE | ID: mdl-35670466

RESUMEN

The aim of this study was the determination of co-formulants in 15 different chlorantraniliprole- and difenoconazole-based plant protection products (PPPs) belonging to different formulations. Samples were analyzed by ultrahigh-performance liquid chromatography coupled to Q-Orbitrap high-resolution mass accuracy spectrometry (UHPLC-Q-Orbitrap-MS), operating in full-scan MS and data-dependent acquisition (ddMS2) modes. A total of 78 co-formulants were tentatively identified by a combination of suspect screening and unknown analysis. Nine of them were later confirmed by analytical standards. Finally, the analytical method was successfully validated and co-formulants were quantified. Linear alkyl ethoxylates (LAS) were the most common type of co-formulant, followed by sodium alkylbenzene sulfonates. Moreover, sodium dodecyl benzene sulfonate had the highest concentration of any co-formulant (up to 32.33 g/L). In all, an innovative identification of co-formulants in a large number of PPPs is presented, which will give room for future studies delving into the composition of PPPs or determining these co-formulants in environmental or agricultural samples.


Asunto(s)
Agricultura , Alcanosulfonatos , Cromatografía Líquida de Alta Presión/métodos , Cromatografía Liquida , Espectrometría de Masas/métodos
4.
Foods ; 10(9)2021 Aug 28.
Artículo en Inglés | MEDLINE | ID: mdl-34574136

RESUMEN

A method was developed for the determination of mineral oil saturated hydrocarbons (MOSH) and mineral oil aromatic hydrocarbons (MOAH) in edible oils, achieving similar limits of quantification than those obtained by online extraction methodologies, i.e., 0.5 mg/kg. The isolation of MOSH and MOAH was performed in a silver nitrated silica gel stationary phase prior to their analysis by gas chromatography-flame ionization detector (GC-FID). To improve the sensitivity, the simulated on-column injection method, using a suitable liner, was optimized. The method was validated at 0.5, 10.0 and 17.9 mg/kg, and recoveries ranged from 80 to 110%. Intra and inter-day precision were evaluated at the same levels, and relative standard deviation (RSD) was lower than 20%. The method was applied to a total of 27 samples of different types of oil previously analyzed in an accredited laboratory, detecting MOSH up to 79.2 mg/kg and MOAH up to 22.4 mg/kg.

5.
J Neural Eng ; 18(4)2021 06 04.
Artículo en Inglés | MEDLINE | ID: mdl-33752175

RESUMEN

Objective.Powered exoskeletons have been used to help persons with gait impairment regain some walking ability. However, little is known about its impact on neuromuscular coordination in persons with stroke. The objective of this study is to investigate how a powered exoskeleton could affect the neuromuscular coordination of persons with post-stroke hemiparesis.Approach.Eleven able-bodied subjects and ten stroke subjects participated in a single-visit treadmill walking assessment, in which their motion and lower-limb muscle activities were captured. By comparing spatiotemporal parameters, kinematics, and muscle synergy pattern between two groups, we characterized the normal gait pattern and the post-stroke motor deficits. Five eligible stroke subjects received exoskeleton-assisted gait trainings and walking assessments were conducted pre-intervention (Pre) and post-intervention (Post), without (WO) and with (WT) the exoskeleton. We compared their gait performance between (a) Pre and Post to investigate the effect of exoskeleton-assisted gait training and, (b) WO and WT the exoskeleton to investigate the effect of exoskeleton wearing on stroke subjects.Main results.While four distinct motor modules were needed to describe lower-extremity activities during stead-speed walking among able-bodied subjects, three modules were sufficient for the paretic leg from the stroke subjects. Muscle coordination complexity, module composition and activation timing were preserved after the training, indicating the intervention did not significantly change the neuromuscular coordination. In contrast, walking WT the exoskeleton altered the stroke subjects' synergy pattern, especially on the paretic side. The changes were dominated by the activation profile modulation towards the normal pattern observed from the able-bodied group.Significance.This study gave us some critical insight into how a powered exoskeleton affects the stroke subjects' neuromuscular coordination during gait and demonstrated the potential to use muscle synergy as a method to evaluate the effect of the exoskeleton training.This study was registered at ClinicalTrials.gov (identifier: NCT03057652).


Asunto(s)
Dispositivo Exoesqueleto , Trastornos Neurológicos de la Marcha , Rehabilitación de Accidente Cerebrovascular , Accidente Cerebrovascular , Fenómenos Biomecánicos , Marcha , Trastornos Neurológicos de la Marcha/etiología , Humanos , Músculos , Accidente Cerebrovascular/complicaciones , Caminata
6.
J Chromatogr A ; 1639: 461940, 2021 Feb 22.
Artículo en Inglés | MEDLINE | ID: mdl-33548662

RESUMEN

The development and validation of a method for the analysis of traces of 3-monochloropropanediol (3-MCPD) esters (19) and glycidyl esters (7) of fatty acids in vegetable oils, margarine, biscuits and croissants was performed. An extraction method based on the use of solvents (tert­butyl methyl ether (20% ethyl acetate, v/v)) was carried out and cleaning of the extract with a mixture of sorbents (Si-SAX, PSA and Z-sep+) was optimized for the elimination of fatty interferents. The analysis of the targeted compounds was carried out by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry, using a triple quadrupole analyzer (UHPLC-MS/MS-QqQ). The validation of the method provided trueness values between 72 and 118% and precision lower than 20%. The limits of quantification ranged from 0.01 to 0.1 mg kg-1, which were below the current legal limits. Twenty samples of vegetable oils as well of 4 samples of margarine, biscuits and croissants were analyzed. Six out of the 24 samples (25%) exceeded the limits set by European legislation, and a maximum contamination of 3-MCPD esters at 2.52 mg kg-1 was obtained in a sample of corn oil (being 1-myristoyl-3-MCPD the compound detected at the highest concentration). A maximum concentration of glycidyl esters at 7.84 mg kg-1 was determined in a soybean oil sample (glycidyl linoleate as the main compound). Only one sample of olive oil exceeded the maximum allowable limit for 3-MCPD esters with a value of 1.72 mg kg-1, expressed as 3-MCPD.


Asunto(s)
Cromatografía Líquida de Alta Presión/métodos , Ésteres/análisis , Espectrometría de Masas en Tándem/métodos , alfa-Clorhidrina/análisis , Compuestos Epoxi/análisis , Ácidos Grasos/análisis , Contaminación de Alimentos/análisis , Límite de Detección , Margarina/análisis , Aceite de Oliva/análisis , Propanoles/análisis , Estándares de Referencia , Reproducibilidad de los Resultados , Aceite de Soja/análisis
7.
Food Chem ; 343: 128495, 2021 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-33160779

RESUMEN

A single method was developed for the determination of polar pesticides (fosetyl-Al and its metabolite, phosphonic acid, and ethephon) and environmental contaminants (chlorate and perchlorate) in edible oils and nuts. Two extraction methods based on QuPPe-PO approach (Quick Polar Pesticides Method for products of Plant Origin) were optimized. In oils, a single extraction using water acidified with formic acid (1%) was performed, while in nuts, the clean-up step was modified. C18 was used as sorbent and an extra cleaning step with n-hexane was added. The extracts were analysed by liquid chromatography coupled to a triple quadrupole mass analyser (LC-QqQ-MS/MS). The method was validated and the limit of quantification was 0.01 mg kg-1 for all analyte-matrix combination. Recoveries from 70 to 120%, and intra and inter-day precision values ≤20% were obtained. Forty samples of edible oils and nuts were analysed, detecting phosphonic acid in nuts at concentrations up to 4.6 mg kg-1.


Asunto(s)
Cromatografía Liquida , Análisis de los Alimentos/métodos , Contaminación de Alimentos/análisis , Nueces/química , Plaguicidas/análisis , Aceites de Plantas/química , Espectrometría de Masas en Tándem , Plaguicidas/química , Plaguicidas/aislamiento & purificación , Extracción en Fase Sólida
8.
Food Chem ; 344: 128729, 2021 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-33277122

RESUMEN

Reduced pesticides use, alongside increased organic farming, has created a need for new biological products, such as thiocyclam, to control pests. Thiocyclam has scarcely been studied, making the study of its degradation in fruits and vegetables, such as tomatoes, an urgent requirement. To monitor thiocyclam metabolites in tomato, dissipation studies were carried out using a liquid chromatography-Orbitrap mass spectrometry (UHPLC-Orbitrap MS) method for 60-days after foliar application. Thiocyclam was not persistent (DT50 < 15 days), but nereistoxin - its primary metabolite - remained present in the tomatoes for >60 days. Four nereistoxin metabolites, detected at low concentrations (<100 µg/kg), were also monitored. This is the first time a study has provided dissipation patterns for thiocyclam and nereistoxin. The results obtained suggest revising the legislation concerning these compounds is required. Toxicological studies must also be carried out because there is no toxicity data currently for thiocyclam or nereistoxin.


Asunto(s)
Cromatografía Líquida de Alta Presión , Compuestos Heterocíclicos con 1 Anillo/análisis , Laboratorios , Espectrometría de Masas , Plaguicidas/análisis , Solanum lycopersicum/química , Frutas/química , Compuestos Heterocíclicos con 1 Anillo/metabolismo , Solanum lycopersicum/metabolismo , Toxinas Marinas/análisis , Toxinas Marinas/metabolismo , Plaguicidas/metabolismo , Medición de Riesgo
9.
Food Res Int ; 133: 109130, 2020 07.
Artículo en Inglés | MEDLINE | ID: mdl-32466927

RESUMEN

A wide-scope analytical method was developed and validated for the determination of tropane alkaloids (TAs) in honey samples. A simple and fast extraction procedure, using a mixture of methanol/water/formic acid (75/25/0.4, v/v/v) as extraction solvent, followed by a clean-up with graphitized black carbon (GBC) and magnesium sulphate was optimized, and compounds were analysed by liquid chromatography coupled to high resolution mass spectrometry (LC-HRMS-Orbitrap). Validation of the proposed method provided adequate linearity (R2 > 0.99), trueness (recoveries 71-120%) and precision (relative standard deviation, RSD ≤ 20.1%), with limits of quantitation (LOQs) at 20 µg/kg (except anisodamine and scopolamine at 40 µg/kg) and a significant matrix effect (≤-50%). Nineteen honey samples were analysed, but only one was positive, containing 27 µg/kg of scopolamine. Additionally, a post-targeted screening was performed, and 47% of samples were contaminated with different herbicides, insecticides and veterinary drugs. Therefore, the proposed analytical method is a powerful tool for both targeted TAs and post-targeted contaminant analyses.


Asunto(s)
Cromatografía Liquida , Contaminación de Alimentos/análisis , Miel/análisis , Espectrometría de Masas , Tropanos/análisis , Estudios Retrospectivos
10.
Anal Bioanal Chem ; 412(18): 4301-4311, 2020 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-32350579

RESUMEN

In this study, the identification of adjuvants (surfactants and solvents) in quizalofop-p-ethyl plant protection products (PPPs) was carried out by applying nuclear magnetic resonance (NMR), ultra-high-performance liquid chromatography (UHPLC) and gas chromatography (GC), both coupled to high-resolution mass spectrometry (HRMS), and using a suspect analysis approach. NMR provided a rapid and global overview of the composition of the studied samples and supported the tentative identification of the glycol ether family, commonly employed as surfactants, and 2-ethyl-1-butanol. UHPLC-HRMS was used for characterization of the glycol polymer surfactants, while GC-HRMS was used to obtain information about volatile organic compounds (benzene or naphthalene derivates) present in the PPPs. A total of nine adjuvants were characterized in the tested PPPs, belonging to naphthalene, benzene, sulphate and fatty acid esters of glycerol families. In addition, the estimation of compound concentrations was carried out using GC(LC)-HRMS, and finally, these concentration levels were related to their toxicity values.


Asunto(s)
Derivados del Benceno/análisis , Ácidos Grasos/análisis , Glicoles/análisis , Naftalenos/análisis , Cromatografía Líquida de Alta Presión/métodos , Cromatografía de Gases y Espectrometría de Masas/métodos , Espectroscopía de Resonancia Magnética/métodos , Alcoholes de Triosa/análisis , Flujo de Trabajo
11.
Foods ; 9(5)2020 May 01.
Artículo en Inglés | MEDLINE | ID: mdl-32370015

RESUMEN

Nowadays, highly polar pesticides are not included in multiresidue methods due to their physico-chemical characteristics and therefore, specific analytical methodologies are required for their analysis. Laboratories are still looking for a pluri-residue method that encompasses the largest number of polar pesticides. The aim of this work was the simultaneous determination of ethephon, 2-hydroxyethylphosphonic acid (HEPA), fosetyl aluminum, glyphosate, aminomethylphosphonic acid (AMPA), N-acetyl-glyphosate and N-acetyl-AMPA in tomatoes, oranges, aubergines and grapes. For that purpose, an ultra high performance liquid chromatography (UHPLC) coupled to a high resolution single mass spectrometer Orbitrap-MS were used. Different stationary phases were evaluated for chromatographic separation, and among them, the stationary phase Torus DEA provided the best separation of the selected compounds. The QuPPe method was used for the extraction of the analytes, but slight modifications were needed depending on the matrix. The developed method was validated, observing matrix effect in all matrices. Intra- and inter-day precision were estimated, and relative standard deviation were lower than 19%. Recoveries were satisfactory, and mean values ranged from 70% to 110%. Limits of quantification were between 25 and 100 µg kg-1. Finally, the analytical method was applied to different fruits and vegetables (oranges, tomatoes, aubergines and grapes).

12.
J Chromatogr A ; 1619: 460964, 2020 May 24.
Artículo en Inglés | MEDLINE | ID: mdl-32113640

RESUMEN

As a novelty, the combination of headspace solid phase microextraction and gas chromatography coupled to an Orbitrap mass analyzer in full scan mode (HS-SPME-GC-Orbitrap-MS) was evaluated for the monitoring of organic pollutants in wastewaters. The developed methodology showed good linearity (R2 > 0.999), sensitivity as well as suitable relative recoveries (89-115%) and precision values (RSD = 1-16%) for 15 polycyclic aromatic hydrocarbons (PAHs) selected as target compounds. Naphthalene, acenapthene and phenanthrene were found in the analyzed samples (influent and effluent wastewaters). Naphthalene was present in 62% of them, ranging from 1.33 to 24.32 ng L-1. Acenapthene was observed in 1 single sample (4.17 ng L-1) while phenanthrene was found in 7 samples (1.51-8.67 ng L-1). In addition, in order to identify other pollutants in the samples, retrospective analyses were addressed through target and non-target screenings. An in-house database containing close to 1,000 pollutants including, among others, polychlorinated biphenyls (PCBs), brominated diphenyl ethers (BDEs) and pesticides, was applied in the post-target analysis. For the non-target screening, after a deconvolution process, high resolution filtering (HRF) and Kovats retention index (KI) were used for tentative analyte identification. Thus, 51 additional pollutants were tentatively identified in the wastewaters, most of them used as flavoring agents and household product ingredients, highlighting the presence of linear alkyl benzenes (LABs).


Asunto(s)
Monitoreo del Ambiente/métodos , Aguas Residuales/química , Contaminantes Químicos del Agua/análisis , Cromatografía de Gases y Espectrometría de Masas , Éteres Difenilos Halogenados/análisis , Espectrometría de Masas , Plaguicidas/análisis , Bifenilos Policlorados/análisis , Hidrocarburos Policíclicos Aromáticos/análisis , Estudios Retrospectivos , Microextracción en Fase Sólida
13.
Food Chem ; 317: 126363, 2020 Jul 01.
Artículo en Inglés | MEDLINE | ID: mdl-32086119

RESUMEN

1H NMR spectroscopy combined with chemometrics was applied for the first time for golden rum classification based on several factors as fermentation barrel, raw material, distillation method and aging. Principal component analysis (PCA) was used to assess the overall structure, and partial least square discriminant analysis (PLS-DA) was carried out for the analytical discrimination of rums. Additionally, data-fusion of 1H NMR and chromatographic techniques (gas and liquid chromatography) coupled to mass spectrometry was applied to provide more accurate knowledge about rums. This approach provided a classification of samples with lower error rate than the one obtained by the use of a single technique (spectroscopic or chromatographic). The results showed that 1H NMR spectroscopy is an appropriate technique for the suitable classification of >95.5% of the samples. When data fusion methodology of spectroscopic and spectrometric data was performed, the prediction efficiency can reach 100% of the samples.


Asunto(s)
Bebidas Alcohólicas/análisis , Metabolómica/métodos , Espectroscopía de Protones por Resonancia Magnética , Cromatografía Líquida de Alta Presión , Análisis Discriminante , Cromatografía de Gases y Espectrometría de Masas , Análisis de los Mínimos Cuadrados , Espectrometría de Masas , Análisis Multivariante , Análisis de Componente Principal
14.
J Neural Eng ; 16(5): 056027, 2019 09 17.
Artículo en Inglés | MEDLINE | ID: mdl-31220818

RESUMEN

OBJECTIVE: Accurate implementation of real-time non-invasive brain-machine/computer interfaces (BMI/BCI) requires handling physiological and nonphysiological artifacts associated with the measurement modalities. For example, scalp electroencephalographic (EEG) measurements are often considered prone to excessive motion artifacts and other types of artifacts that contaminate the EEG recordings. Although the magnitude of such artifacts heavily depends on the task and the setup, complete minimization or isolation of such artifacts is generally not possible. APPROACH: We present an adaptive de-noising framework with robustness properties, using a Volterra based non-linear mapping to characterize and handle the motion artifact contamination in EEG measurements. We asked healthy able-bodied subjects to walk on a treadmill at gait speeds of 1-to-4 mph, while we tracked the motion of select EEG electrodes with an infrared video-based motion tracking system. We also placed inertial measurement unit (IMU) sensors on the forehead and feet of the subjects for assessing the overall head movement and segmenting the gait. MAIN RESULTS: We discuss in detail the characteristics of the motion artifacts and propose a real-time compatible solution to filter them. We report the effective handling of both the fundamental frequency of contamination (synchronized to the walking speed) and its harmonics. Event-related spectral perturbation (ERSP) analysis for walking shows that the gait dependency of artifact contamination is also eliminated on all target frequencies. SIGNIFICANCE: The real-time compatibility and generalizability of our adaptive filtering framework allows for the effective use of non-invasive BMI/BCI systems and greatly expands the implementation type and application domains to other types of problems where signal denoising is desirable. Combined with our previous efforts of filtering ocular artifacts, the presented technique allows for a comprehensive adaptive filtering framework to increase the EEG signal to noise ratio (SNR). We believe the implementation will benefit all non-invasive neural measurement modalities, including studies discussing neural correlates of movement and other internal states, not necessarily of BMI focus.


Asunto(s)
Artefactos , Electroencefalografía/métodos , Prueba de Esfuerzo/métodos , Marcha/fisiología , Movimiento (Física) , Caminata/fisiología , Adulto , Electroencefalografía/normas , Prueba de Esfuerzo/normas , Humanos
15.
Food Chem ; 288: 22-28, 2019 Aug 01.
Artículo en Inglés | MEDLINE | ID: mdl-30902285

RESUMEN

An analytical method based on a QuEChERS procedure (quick, easy, cheap, effective, rugged and safe) has been developed for the determination of mycotoxins (α-zearalenol and zearalenone, and aflatoxins B1, B2, G1 and G2) in edible oils. The analysis was performed by ultra-high performance liquid chromatography coupled to triple quadrupole analyser (UHPLC-QqQ-MS/MS). The method was fully validated and the quantification limit is 0.5 µg kg-1 for aflatoxins and 1 µg kg-1 for α-zearalenol and zearalenone. Suitable recoveries were obtained at low concentration levels (0.5-25 µg kg-1 for aflatoxins and 1-25 µg kg-1 for α-zearalenol and zearalenone), ranging from 80 to 120%. Intra and inter-day precision values were also evaluated and relative standard deviation was lower than 20%. The expanded uncertainty, U, was also evaluated ant it was below 32% at 25 µg kg-1. The validated method has been applied to monitor the presence of mycotoxins in 194 samples belonging to different types of edible oils (olive oil, sunflower oil, soy oil and corn oil). Zearalenone was detected in 25% of the analysed samples at concentrations up to 25.6 µg kg-1, and aflatoxin G1 and G2 in 3% and 14% of the samples at a maximum concentration of 1.9 and 6.8 µg kg-1 respectively.


Asunto(s)
Cromatografía Líquida de Alta Presión , Micotoxinas/análisis , Aceites de Plantas/metabolismo , Espectrometría de Masas en Tándem , Aflatoxinas/análisis , Límite de Detección , Aceite de Oliva/metabolismo , Zearalenona/análisis , Zeranol/análogos & derivados , Zeranol/análisis
16.
J Agric Food Chem ; 67(4): 1284-1291, 2019 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-30636415

RESUMEN

In this study, several calystegines (A3, A5, B1, B2, B3, B4, and C1) were determined in tomato. A simple extraction followed by a derivatization step with silylating agents was performed prior to their analysis by gas chromatography coupled to high resolution mass spectrometry (GC-HRMS-Q-Orbitrap), which allowed the monitoring of several ions at accurate mass. The validation of the method has provided suitable values of linearity, trueness (73.7-120.0%), and precision (≤20.0%, except for calystegines B3 and B4 at 0.5 mg/kg). The limit of quantitation was set at 0.5 mg/kg for all analytes. The validated method was successfully applied to the analysis of nine different tomato varieties, and calystegines A3, A5, B2, and C1 were found at concentrations ranging between 0.65 mg/kg (C1) and 12.47 mg/kg (B2). Tomato varieties were classified according to their calystegines content by applying an analysis of variance (ANOVA).


Asunto(s)
Cromatografía de Gases y Espectrometría de Masas/métodos , Extractos Vegetales/química , Solanum lycopersicum/química , Tropanos/química , Análisis de Varianza , Solanum lycopersicum/clasificación
17.
J Agric Food Chem ; 67(4): 1302-1311, 2019 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-30618256

RESUMEN

A comprehensive fingerprinting strategy for golden rum classification considering different categories such as fermentation barrel, raw material, and aging is provided, using a metabolomic fingerprinting approach. A nontarget fingerprinting of 30 different rums using liquid chromatography coupled to high-resolution mass spectrometry (Exactive Orbitrap mass analyzer, LC-HRMS) was applied. Principal component analysis (PCA) was used to assess the overall structure of the data and to identify potential outliers. Different chemometric analyses such as partial least-squares discriminant analysis (PLS-DA) were used. A variable importance in projection (VIP) selection method was applied to identify the most significant markers that allow group separation. Compounds related to aging and fermentation processes such as furfural derivates (e.g., hydroxymethylfurfural) and sugars (e.g., glucose, mannitol) were found as the most discriminant compounds (VIP threshold value >1.5). Suitable separation according to selected categories was achieved, and a classification ability of the models of close to 100% was achieved.


Asunto(s)
Bebidas Alcohólicas/análisis , Técnicas de Química Analítica/métodos , Cromatografía Líquida de Alta Presión/métodos , Espectrometría de Masas/métodos , Metabolómica/métodos , Bebidas Alcohólicas/clasificación , Análisis Discriminante , Análisis de Componente Principal , Control de Calidad
18.
J AOAC Int ; 2018 Oct 10.
Artículo en Inglés | MEDLINE | ID: mdl-30305207

RESUMEN

Background: Automated methods are needed for the reliable determination of xenobiotics in environmental samples. Objective: Optimization and application of an automated method for the ultra-trace analysis of 34 organic contaminants including polycyclic aromatic hydrocarbons (PAHs), polybrominated diphenyl ethers (PBDEs), polychlorinated biphenyls (PCBs), organochlorinated (OCPs), and organophosphorus pesticides (OPPs) in sediment samples have been performed. Methods: Automated method based on headspace solid-phase microextraction (SPME) coupled to GC-high-resolution MS (GC-HRMS) for the ultra-trace analysis of the targeted compounds has been developed. Conclusions: Suitable validation parameters in terms of linearity, trueness, selectivity, intraday and interday precision, LODs, and LOQs were obtained. Relative recovery values between 70 and 120% were achieved for all compounds (concentration levels assayed 1 and 10 µg/kg). RSD values were always lower than 25% for intra- and interday precision, and LODs and LOQs were 0.1 and 1.0 µg/kg, respectively, for all analytes. Highlights: The proposed method was applied to the analysis of sediments collected in Andalusia, Spain, and Poland, finding PCB 18 in one sample (15.9 µg/kg) and p,p'-DDE in several samples at concentrations ranging from 27.6 to 297.2 µg/kg.

19.
Analyst ; 143(19): 4707-4714, 2018 Sep 24.
Artículo en Inglés | MEDLINE | ID: mdl-30183032

RESUMEN

Quantitative boron-11 NMR (11B qNMR) spectroscopy has been introduced for the first time as a method to determine boric acid content in commercial biocides. Validation of the method affords a limit of detection of 0.02% w/w and a limit of quantification of 0.04% w/w, which are low enough to determine boric acid in commercial biocides. Other figures of merit such as linearity (R2 > 0.99), recovery (93.6%-106.2%), intra- and inter-day precision (from 0.7 to 2.0%), uncertainty (3.7 to 4.4%) and matrix effects were also evaluated. This method was successfully applied to determine boric acid in five different commercial biocides in a wide range of concentrations (<0.05 to 10% w/w) providing excellent results when they were compared with those obtained using inductively coupled plasma-mass spectrometry (ICP-MS). The suitability of this method for a fast and reliable quantification of boric acid in commercial biocide preparations has been demonstrated. The absence of the matrix effect allows the application of this validated method for the determination of boric acid in other matrices of diverse composition.

20.
J Chromatogr A ; 1576: 51-57, 2018 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-30245074

RESUMEN

Taking into account the high consumption of tomato and tomato-based products, a study of the occurrence of 7 nortropane alkaloids (calystegines A3, A5, B1, B2, B3, B4 and C1) in this type of matrix has been performed. For that purpose, a simple and fast solid-liquid extraction with methanol/water (50/50, v/v) has been developed, and then liquid chromatography, using a HILIC-A as stationary phase, coupled to high resolution mass spectrometry (LC-HRMS-Orbitrap) has been used for their determination. The developed method was validated and recoveries ranged from 96 to 121%, and relative standard deviations lower than or equal to 16% were obtained. Limits of quantification (LOQ) were established at 0.1 (B4), 0.25 (B3) and 0.5 (A3, A5, B1, B2 and C1) mg/kg. Twelve different samples were analyzed, comprising 4 crushed tomatoes, 4 fried tomatoes and 4 jam tomatoes. Calystegines A3 and B2 were identified in all the analyzed samples, while calystegine B3 was determined in all the fried tomatoes as well as in two crushed tomatoes and one jam tomato at concentrations ranging from 0.4 mg/kg (calystegine B2) to 19.0 mg/kg (calystegine A3). Although calystegine A5 was also detected in all the samples, only 3 of them gave concentrations higher than LOQ. Additionally, calystegine B1 was found in one jam tomato at 1.9 mg/kg.


Asunto(s)
Cromatografía Liquida , Análisis de los Alimentos/métodos , Alcaloides Solanáceos/análisis , Solanum lycopersicum/química , Espectrometría de Masas en Tándem , Alcaloides Solanáceos/química
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