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1.
Biomed Chromatogr ; 34(1): e4725, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31755114

RESUMO

For the analysis of methylhippuric acids (MHAs) in human urine samples, in this study, a new method based on the metal-organic framework (MOF) of MIL-53-NH2 (Al) in microextraction by packed sorbent (MEPS) was developed. The synthesis of MIL-53-NH2 (Al) was characterized by Fourier transform infrared spectra, field emission-scanning electron microscopy and X-ray diffraction. Response surface methodology was used to investigate the influences of several parameters including type and volume of elution, type of conditional solvent, sample volume and extraction cycle on MEPS efficiency. The results showed good recoveries (>94%) and excellent extraction efficiencies (>96%) at three different concentrations of 50, 500 and 1500 µg ml-1 (as low, mid and high concentrations, respectively) of MHA isomers. Calibration curves of MHAs were linear over the concentration range of 1-1500 µg ml-1 , with high correlation coefficients (r ≥ 0.998). The reproducibility of the proposed MIL-53-MEPS for determination of three isomers of MHA was found to be in the range of 3.5-11.1%. After optimization of the proposed technique, it was used to analyze MHAs in urine samples of workers exposed to xylenes in a petrochemical plant in Asalouyah, Iran. The results indicated that the MOF-MEPS method was selective, sensitive, rapid and efficient for the extraction of urinary MHAs. The technique is also environmentally friendly and inexpensive, and the MOF sorbent is reusable.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Hipuratos/urina , Estruturas Metalorgânicas/química , Microextração em Fase Sólida/métodos , Desenho de Equipamento , Humanos , Limite de Detecção , Modelos Lineares , Exposição Ocupacional/análise , Reprodutibilidade dos Testes , Microextração em Fase Sólida/instrumentação
2.
J Sci Food Agric ; 100(3): 945-952, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31489633

RESUMO

BACKGROUND: Watermelon is appreciated for its nutritional properties and for its flavor. Among the flavor-active compounds that it contains, volatiles play a key role being responsible for aroma. Recent breeding activity has led to the release of mini-watermelons with reduced fruit weight. This paper reports on the characterization of aroma profiles of 'Rugby' and 'Cuoredolce®' novel mini-watermelon cultivars at the ripening stage. The main volatiles were identified and quantified using headspace solid-phase microextraction gas-chromatography mass spectrometry (HS-SPME-GC-MS), and their concentrations were correlated with the E-nose profile. The potential contribution of volatile compounds to the fruit aroma was evaluated by computing the odor activity values (OAV). RESULTS: Twenty main volatile compounds were identified: aldehydes (9), alcohols (4), ketones (2), and terpenes and terpenoids (5). C-9 aldehydes and alcohols were the prevalent compounds. The two cultivars differed in precocity, with 'Rugby' being riper from the early stage considered. Many apocarotenoids with desirable olfactory notes were detected in the volatile profile of 'Rugby'. Four e-nose sensors' signals significantly changed with variety and ripening stage: W1W and W2W were positively correlated and W6S was negatively correlated with all identified volatiles, while W3S showed a negative correlation with 6-methyl-5-hepten-2-one, the major lycopene catabolite. CONCLUSIONS: The aroma profiles described here contribute to the characterization of 'Cuoredolce®' and 'Rugby' mini-watermelon cultivars. Electronic-nose measurement was able to discriminate between cultivars and, to a lesser extent, among ripening stages. © 2019 Society of Chemical Industry.


Assuntos
Citrullus/química , Frutas/crescimento & desenvolvimento , Compostos Orgânicos Voláteis/química , Citrullus/classificação , Citrullus/crescimento & desenvolvimento , Frutas/química , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/isolamento & purificação
3.
J Forensic Sci ; 65(1): 134-143, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31479524

RESUMO

Volatile organic compounds (VOCs) are by-products of cadaveric decomposition and are responsible for the odor associated with decomposing remains. The direct link between VOC production and individual postmortem microbes has not been well characterized experimentally. The purpose of this study was to profile VOCs released from three postmortem bacterial isolates (Bacillus subtilis, Ignatzschineria indica, I. ureiclastica) using solid-phase microextraction arrow (SPME Arrow) and gas chromatography-mass spectrometry (GC-MS). Species were inoculated in headspace vials on Standard Nutrient Agar and monitored over 5 days at 24°C. Each species exhibited a different VOC profile that included common decomposition VOCs. VOCs exhibited upward or downward temporal trends over time. Ignatzschineria indica produced a large amount of dimethyldisulfide. Other compounds of interest included alcohols, aldehydes, aromatics, and ketones. This provides foundational data to link decomposition odor with specific postmortem microbes to improve understanding of underlying mechanisms for decomposition VOC production.


Assuntos
Bacillus subtilis/metabolismo , Gammaproteobacteria/metabolismo , Mudanças Depois da Morte , Compostos Orgânicos Voláteis/metabolismo , Animais , Medicina Legal , Cromatografia Gasosa-Espectrometria de Massas , Microextração em Fase Sólida , Suínos
4.
Food Chem ; 307: 125556, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31648180

RESUMO

The verification of the geographical origin of extra virgin (EVOO) and virgin olive oil (VOO) is crucial to protect consumers from misleading information. Despite the large number of studies performed, specific markers are still not available. The present study aims to evaluate sesquiterpene hydrocarbons (SHs) as markers of EVOO geographical origin and to compare the discrimination efficiency of targeted profiling and fingerprinting approaches. A prospective study was carried out on 82 EVOOs from seven countries, analyzed by Headspace Solid Phase Microextraction-Gas Chromatography-Mass Spectrometry (HS-SPME-GC-MS). Classification models were developed by Partial Least Square-Discriminant Analysis (PLS-DA) and internally validated (leave 10%-out cross-validation). The percentage of correct classification was higher for the fingerprinting (100%) than for the profiling approach (45.5-100%). These results confirm the suitability of SHs as EVOO geographical markers and establish the fingerprinting as the most efficient approach for the treatment of SH analytical data with this purpose up to date.


Assuntos
Azeite de Oliva/química , Sesquiterpenos/análise , Fraude , Cromatografia Gasosa-Espectrometria de Massas , Geografia , Azeite de Oliva/análise , Estudos Prospectivos , Microextração em Fase Sólida
5.
Food Chem ; 308: 125607, 2020 Mar 05.
Artigo em Inglês | MEDLINE | ID: mdl-31677599

RESUMO

Lipid sources as alternatives to fish oil could alter the nutritional value and flavor quality of crab meat affecting consumer preferences. Herein, an 8-week nutritional trial was designed to investigate the effects of dietary lipid sources including fish oil (FO), krill oil (KO), palm oil, rapeseed oil, soybean oil and linseed oil on profiles of amino acids, fatty acids and volatiles in muscle of swimming crab (Portunus trituberculatus). Volatiles of crab muscle were characterized by headspace solid-phase microextraction and gas chromatography-tandem mass spectrometry. Results revealed that crabs fed FO and KO had significantly higher levels of protein, indispensable amino acids, eicosapentaenoic acid and docosahexaenoic acid in muscle. Principal component analysis and hierarchical cluster analysis demonstrated that muscle volatiles of crabs fed different dietary oils exhibited significant variations. Dietary FO and KO significantly increased the relative levels of 3-methylbutanal, heptanal, benzaldehyde and nonanal in muscle, which may produce more pleasant flavors.


Assuntos
Braquiúros/química , Aromatizantes/análise , Animais , Gorduras na Dieta/análise , Ácidos Docosa-Hexaenoicos/análise , Ácido Eicosapentaenoico/análogos & derivados , Ácido Eicosapentaenoico/análise , Ácidos Graxos/análise , Cromatografia Gasosa-Espectrometria de Massas/métodos , Estado Nutricional , Valor Nutritivo , Alimentos Marinhos/análise , Microextração em Fase Sólida , Natação , Paladar
6.
Chemosphere ; 240: 124951, 2020 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-31574445

RESUMO

A high demand exists in human biomonitoring studies for reliable and straightforward methods that generate data faster and simultaneously. Thus, the present study combines microextraction by packed sorbent (MEPS) and liquid chromatography coupled to mass spectrometry (LC-MS/MS) for simultaneous extraction and determination of various classes of endocrine-disrupting chemicals (EDCs), including parabens, benzophenones, bisphenols, and the antimicrobial, triclocarban in human urine samples. Optimized MEPS conditions were: i) MEPS sorbent (C18), ii) pH of sample (3), iii) volume of sample (250 µL), iv) number of draws-eject cycles (5) and (vi) desorption solvent conditions (100 µL of CH3OH:H2O 80:20 v/v). The calibration curves were linear over the selected ranges for all studied compound, with correlation coefficients higher than 0.99. The variation coefficient for precision was lower than 20% at lower concentrations and lower than 15% at the higher concentrations studied. The accuracy ranged from 90% to 118%. The proposed strategy affords several advantages over currently published approaches, including simplicity of operation and reduction of sample and solvent volumes and time for matrix clean-up. Moreover, the analytical performance of each MEPS cartridge remained stable over the analysis of at least 70 samples (RSD < 10%). Thus, the current procedure may be an interesting high-throughput alternative for large routine human biomonitoring studies. Urinary geometric mean concentrations of EDCs obtained in this study were close than those previously reported for Brazilian children.


Assuntos
Compostos Benzidrílicos/urina , Benzofenonas/urina , Carbanilidas/urina , Disruptores Endócrinos/urina , Parabenos/análise , Fenóis/urina , Brasil , Calibragem , Criança , Cromatografia Líquida de Alta Pressão/métodos , Cromatografia Líquida , Humanos , Limite de Detecção , Microextração em Fase Sólida/métodos , Espectrometria de Massas em Tandem/métodos
7.
J Chem Ecol ; 46(1): 21-29, 2020 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-31853815

RESUMO

Female Helicoverpa armigera emit a pheromone, comprised of a 98:2 ratio of (Z)-11-hexadecenal to (Z)-9-hexadecenal, to attract males. It has been proposed that "immature" female H. armigera modulate attraction of males by emitting an antagonist, (Z)-11-hexadecenol, along with pheromone during the first two nights of calling. However, it is unclear why females would call and simultaneously release pheromone and an antagonist. We conducted observations of female calling during the first five nights after adult emergence to determine periodicity. We also measured the relative abundance of (Z)-11-hexadecenol to the major component, (Z)-11-hexadecenal, on the surface of the gland of calling females and compared it to the ratio of these two compounds inside the gland over the first three nights after adult emergence to determine how much antagonist may be released. We found that young females (< 1-d-old) are unlikely to call and, based on the relative proportion of (Z)-11-hexadecenol on the gland surface, even if they did call would be unlikely to release sufficient (Z)-11-hexadecenol to diminish male attraction.


Assuntos
Fertilidade/fisiologia , Mariposas/fisiologia , Atrativos Sexuais/química , Aldeídos/análise , Aldeídos/isolamento & purificação , Aldeídos/farmacologia , Animais , Cromatografia Gasosa , Feminino , Masculino , Atrativos Sexuais/análise , Atrativos Sexuais/farmacologia , Comportamento Sexual Animal/efeitos dos fármacos , Microextração em Fase Sólida , Estereoisomerismo
8.
Food Chem ; 307: 125542, 2020 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-31639573

RESUMO

This study aimed to develop a headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) method for the quantification of 3-monochloropropane-1,2-diol fatty acid esters (3-MCPDEs) and 2-monochloropropane-1,3-diol fatty acid esters (2-MCPDEs), and semi-quantification of glycidyl fatty acid esters (GEs) in edible oils. A central composite design was implemented to optimize the derivatization temperature and extraction time, which were 100 °C and 80 min, respectively. HS-SPME coupled with in-situ derivatization was more straightforward (three steps) and sensitive, with a limit of detection of 16% (3.9 µg/L) and 11% (5.3 µg/L) higher than that of liquid injection method, for 3-MCPD and 2-MCPD, respectively. The recoveries of 3-MCPD and 2-MCPD were in the range of 91.1% to 102.1%, with a relative standard deviation ranging from 0.08 to 9.29%. The validated methodology was successfully applied to oil samples. Further efforts will focus on shortening the extraction time, as 80 min is relatively long.


Assuntos
Ésteres/análise , Cromatografia Gasosa-Espectrometria de Massas , Glicerol/análogos & derivados , Óleos Vegetais/química , Microextração em Fase Sólida/métodos , alfa-Cloridrina/química , Ésteres/química , Ácidos Graxos/química , Contaminação de Alimentos/análise , Glicerol/química , Limite de Detecção
9.
Food Chem ; 302: 125337, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31419770

RESUMO

The composition of volatile compounds in Korla fragrant pears was determined using headspace solid-phase microextraction followed by a gas chromatography-mass spectrometry analysis using fruits at 30, 90, and 150 days after bloom. Hexanal, (E)-2-hexenal, 1-hexanol, (E)-2-hexen-1-ol, (Z)-3-hexen-1-ol, and hexyl acetate were identified as the major compounds. The composition of volatile compounds was associated with fatty acid concentrations and key enzyme activity in the lipoxygenase pathway. In vitro linoleic and linolenic acid feeding experiments conducted using cubes of fruit flesh demonstrated that the concentrations of volatile esters, such as hexyl acetate, in the treated fruits increased significantly after incubation for 12 h compared with those in the control fruits, which was accompanied by a reduction in aldehyde and alcohol concentrations (p < 0.05 or p < 0.01). However, the treatments did not significantly influence the enzyme activity and expression of genes encoding the enzymes.


Assuntos
Frutas/química , Odorantes/análise , Pyrus/química , Pyrus/fisiologia , Compostos Orgânicos Voláteis/análise , Aldeídos/análise , Ésteres/análise , Ácidos Graxos/análise , Ácidos Graxos/metabolismo , Análise de Alimentos/métodos , Frutas/efeitos dos fármacos , Frutas/fisiologia , Cromatografia Gasosa-Espectrometria de Massas/métodos , Regulação da Expressão Gênica de Plantas , Hexanóis/análise , Ácido Linoleico/farmacologia , Pyrus/efeitos dos fármacos , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/metabolismo , Ácido alfa-Linoleico/farmacologia
10.
Food Chem ; 302: 125370, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442699

RESUMO

Four Arabica coffees (Brazil, Colombia, Ethiopia, and Guatemala) yield highly variant odours, attesting to the complexities of coffee aroma that command advanced analytical tools. In this study, their volatiles were extracted using solvent-assisted flavour evaporation (SAFE) and headspace solid-phase microextraction (HS-SPME). Due to matrix complexity, some trace odourants were detected in SAFE extracts by aroma extract dilution analysis (AEDA) but remained difficult to quantify by gas chromatography-mass spectrometry (GC-MS). This prompted the application of low energy electron ionisation (EI) coupled with GC-quadrupole time-of-flight (GC-QTOF). Optimal low EI GC-QTOF parameters (EI energy: 15 eV, acquisition rate: 3 Hz) were applied to achieve improved molecular ion signal intensity and reproducibility (relative standard deviation < 10%) across five compounds, which resulted in good linearity (R2 ≥ 0.999) and lowered detection levels (e.g. 0.025 ±â€¯0.005 ng/mL for 4-hydroxy-5-methyl-3(2H)-furanone). Therefore, this method potentially improves the measurement of trace odourants in complex matrices by increasing specificity and sensitivity.


Assuntos
Café/química , Análise de Alimentos/métodos , Odorantes/análise , Compostos Orgânicos Voláteis/análise , Adulto , Brasil , Coffea/química , Colômbia , Etiópia , Feminino , Análise de Alimentos/estatística & dados numéricos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Guatemala , Humanos , Masculino , Pessoa de Meia-Idade , Olfatometria/métodos , Extratos Vegetais/química , Análise de Componente Principal , Reprodutibilidade dos Testes , Microextração em Fase Sólida/métodos , Paladar , Compostos Orgânicos Voláteis/isolamento & purificação
11.
J Sci Food Agric ; 100(1): 38-49, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31435935

RESUMO

BACKGROUND: Aromatic compounds are responsible for the final quality of wines. A semi-quantitative analysis was carried out during two consecutive seasons aiming to determine the volatile composition of 12 new white crosses obtained between Monastrell (M) and other varieties, such as Cabernet Sauvignon (C), Syrah (S) and Tempranillo (T) (MC10, MC180, MC9, MC69, MS30, MS33, MS82, MT103, MT19, MV11, MV67 and MV7), using a methodology based on gas chromatography-solid phase microextraction-mass spectrometry. RESULTS: On the one hand, 30 aromatic compounds were identified belonging to different chemical groups (alcohols, acids, terpenes, norisoprenoids and esters). The results showed how some crosses presented significant differences with respect to their parental. For example, in 2016, Monastrell and Cabernet Sauvignon showed high concentration of alcohols, acids and some terpenes, whereas the corresponding crosses showed a predominance of aromas belonging to esters. In 2017, as a result of edaphoclimatic conditions, the white crosses had higher concentrations of esters and acids. In addition, Monastrell and Cabernet Sauvignon showed similar concentrations of alcohols compared to 2016. On the other hand, sensorial analyses confirmed these results, so that mint and peppermint aromas and a fresh quality were detected in MC69 wine, especially in 2016, and fruity and acid aromas were detected in MC180 wine, which gave it a wide ranging complexity and aromatic potential. CONCLUSION: The present study reports the first investigation of the volatile composition and sensory characteristics of directed crosses white wines obtained from Monastrell and other varieties, such as Cabernet Sauvignon, Syrah, Tempranillo and Verdejo. The results obtained indicate that the use of some of these white crosses could be a good option for growing them in this Mediterranean area as a result of the contribution of a good quality in the wine aroma. © 2019 Society of Chemical Industry.


Assuntos
Aromatizantes/química , Compostos Orgânicos Voláteis/química , Vinho/análise , Aromatizantes/isolamento & purificação , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/isolamento & purificação , Vinho/classificação
12.
Food Chem ; 305: 125486, 2020 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-31520920

RESUMO

The formation of 3-methyl-2,4-nonanedione (MND) during red wine aging can contribute to the premature evolution of aroma, characterized by the loss of fresh fruit and development of dried fruit flavors. The identification of two new hydroxy ketones, 2-hydroxy-3-methylnonan-4-one (syn- and anti-ketol diastereoisomers) and 3-hydroxy-3-methyl-2,4-nonanedione (HMND), prompted the investigation of the precursors and pathways through which MND is produced and evolves. An HS-SPME-GC-MS method was optimized for their quantitation in numerous must and wine samples, providing insight into the evolution of MND, HMND, and ketols through alcoholic fermentation and wine aging. Alcoholic fermentation resulted in a significant decrease in MND and HMND and the simultaneous appearance of ketol diastereoisomers. The analysis of 167 dry red wines revealed significant increases in MND and anti-ketol contents through aging and a significant positive correlation between MND and anti-ketols. Additional experiments demonstrated that ketols are precursors to MND during red wine oxidation.


Assuntos
Alcanos/química , Diacetil/análogos & derivados , Sucos de Frutas e Vegetais/análise , Cetonas/análise , Vinho/análise , Alcanos/metabolismo , Diacetil/química , Diacetil/metabolismo , Etanol/química , Cromatografia Gasosa-Espectrometria de Massas , Humanos , Concentração de Íons de Hidrogênio , Cetonas/isolamento & purificação , Limite de Detecção , Microextração em Fase Sólida , Estereoisomerismo , Fatores de Tempo
13.
Talanta ; 206: 120236, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31514837

RESUMO

This work presents a reliable analytical procedure combining micro-extraction by packed sorbent (MEPS) and ultra-high performance liquid chromatography-electrospray ionization tandem mass spectrometry to determine 8-iso prostaglandin F2α, 8-iso prostaglandin E2 and prostaglandin E2 in dried blood spots (DBSs). To reach this goal, we optimized a fast semi-automated MEPS procedure for the clean-up and pre-concentration of the analytes extracted from a single DBS (50 µL) by a 70:30 v/v methanol:water mixture. Limits of detection of about 20 pg mL-1, satisfactory recoveries (90-110%) and very good intra- and inter-day precisions (RSD ≤10%) were obtained for all the analytes. The innovative addition of internal standards on the filter paper before DBS sampling allowed to compensate changes in the amount of analyte during storage. Since prostanoids and isoprostanoids are biomarkers involved in the pathogenesis and progression of many diseases (e.g. ductal patency, diabetic nephropathy, and acute lung injury), our analytical method offers interesting diagnostic and prognostic opportunities in the medical field. The present method is currently used for the analysis of such biomarkers in DBSs from preterm newborns collected in the clinical setting.


Assuntos
Dinoprosta/análogos & derivados , Dinoprostona/análogos & derivados , Dinoprostona/sangue , Teste em Amostras de Sangue Seco/métodos , Isoprostanos/sangue , Biomarcadores/sangue , Cromatografia Líquida de Alta Pressão/métodos , Dinoprosta/sangue , Humanos , Recém-Nascido , Limite de Detecção , Microextração em Fase Sólida/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Espectrometria de Massas em Tandem/métodos
14.
J Agric Food Chem ; 67(49): 13694-13705, 2019 Dec 11.
Artigo em Inglês | MEDLINE | ID: mdl-31756091

RESUMO

Over wood aging, matured spirits developed a complex aromatic bouquet where roasted-like notes were often perceived. Since many nitrogen heterocycles were related to these olfactory nuances, a headspace solid-phase microextraction (HS-SPME) coupled to gas chromatography-mass spectrometry was developed and validated to quantify them in both spirit and wood matrices. The various parameters affecting the extraction of the analytes from both spirit and wood samples were first investigated (i.e., fiber coating phase, dilution, pH and volume sample, adding salt, extraction time and temperature, and incubation time) to determine the best compromise for a single-run analysis of the whole set of studied compounds. Good linearity (R2 > 0.99), repeatability, reproducibility, accuracy and low detection, and quantification limits were obtained, making this analytical method a suitable tool for routine analysis of the selected nitrogen compounds. Fifteen pyrazines, three pyrroles, and three quinolines were quantified in a series of oak wood and commercial spirit samples where some of them were identified for the first time. The significant impact of some barrel features and the spirit in-wood maturation step on the N-heterocycle profile in both matrices were finally discussed.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Compostos Heterocíclicos/química , Compostos Heterocíclicos/isolamento & purificação , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação , Vinho/análise , Madeira/química , Odorantes/análise , Quercus/química
15.
Anal Bioanal Chem ; 411(28): 7387-7398, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31667562

RESUMO

We report a novel, fast, and automatic SPME-based method capable of extracting a small molecule-drug conjugate (SMDC) from biological matrices. Our method relies on the extraction of the drug conjugate followed by direct elution into an electrospray mass spectrometer (ESI-MS) source for qualitative and quantitative analysis. We designed a tool for extracting the targeting head of a recently synthesized SMDC, which includes acetazolamide (AAZ) as high-affinity ligand specific to carbonic anhydrase IX. Specificity of the extraction was achieved through systematic optimization. The design of the extraction tool is based on noncovalent and reversible interaction between AAZ and CAII that is immobilized on the SPME extraction phase. Using this approach, we showed a 330% rise in extracted AAZ signal intensity compared to a control, which was performed in the absence of CAII. A linear dynamic range from 1.2 to 25 µg/ml was found. The limits of detection (LOD) of extracted AAZ from phosphate-buffered saline (PBS) and human plasma were 0.4 and 1.2 µg/ml, respectively. This with a relative standard deviation of less than 14% (n = 40) covers the therapeutic range. Graphical abstract.


Assuntos
Acetazolamida/isolamento & purificação , Inibidores Enzimáticos/química , Bibliotecas de Moléculas Pequenas/isolamento & purificação , Microextração em Fase Sólida/métodos , Espectrometria de Massas por Ionização por Electrospray/métodos , Acetazolamida/química , Automação , Limite de Detecção , Reprodutibilidade dos Testes , Bibliotecas de Moléculas Pequenas/química
16.
Environ Monit Assess ; 191(11): 692, 2019 Oct 30.
Artigo em Inglês | MEDLINE | ID: mdl-31667640

RESUMO

In this study, a rapid and effective dispersive solid-phase microextraction (d-SPME) method was developed to preconcentrate Pd from aqueous extract of soil samples by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS). The unique properties of magnetic nanoparticles (MNPs) were used to directly isolate Pd from the sample solutions without the need for complexation. Significant parameters of the extraction method such as magnetic nanoparticle type and amount, pH and amount of buffer solution, amount of eluent, and mixing type and period were optimized together with other instrumental parameters to boost the absorbance signal of Pd. An SQT was fitted onto the burner head to boost the interaction between Pd atoms and hollow cathode lamp radiation to enhance absorbance signals. The limit of detection (LOD) and limit of quantification (LOQ) values for Pd determined (d-SPME-MNP-SQT-FAAS) were 6.4 and 21.4 ng/mL, respectively. The percentage relative standard deviation of the developed method was calculated as 6.6%. The method was applied to soil samples taken from the campus area and spiked recovery experiments were performed to evaluate the method's accuracy/applicability. Satisfactory percent recovery results (90-101%) were obtained for different spiked concentrations and this proved the accuracy/applicability of the method.


Assuntos
Paládio/análise , Poluentes do Solo/análise , Monitoramento Ambiental/métodos , Limite de Detecção , Microextração em Fase Líquida/métodos , Magnetismo , Nanopartículas de Magnetita , Quartzo/química , Solo , Microextração em Fase Sólida , Espectrofotometria Atômica/métodos , Água/análise
17.
J Agric Food Chem ; 67(47): 13150-13163, 2019 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-31684730

RESUMO

Evolution of the volatile profile of two extra-virgin olive oils with very different fatty acid composition (monounsaturated fatty acid/polyunsaturated fatty acid ratio) stored in several nonaccelerated oxidative conditions was studied by a validated headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS) method. The role of C8 volatile compounds in oxidative processes was highlighted, and controversial aspects regarding the origin of some volatiles were clarified. Specific volatile markers for rancidity were proposed: sum of pentanal, hexanal, nonanal, E-2-heptenal, propanoic acid, and hexanoic acid for oils stored in the dark; sum of pentanal, heptanal, nonanal, decanal, E-2-heptenal, E-2-decenal, E,E-hepta-2,4-dienal, and E,E-deca-2,4-dienal, octane for oils stored under light exposure; sum of pentanal, nonanal, decanal, E-2-heptenal, E-2-decenal, E,E-hepta-2,4-dienal, nonan-1-ol, propanoic acid, octane, 6-methylhept-5-en-2-one, and oct-1-en-3-ol for oils stored under light exposure with oxygen in headspace. A simplified marker (sum of pentanal, nonanal and E-2-heptenal) suitable for all conditions was also proposed.


Assuntos
Azeite de Oliva/química , Compostos Orgânicos Voláteis/química , Aldeídos/análise , Aldeídos/isolamento & purificação , Armazenamento de Alimentos , Cromatografia Gasosa-Espectrometria de Massas , Oxirredução , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/isolamento & purificação
18.
J Chem Ecol ; 45(10): 823-837, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31701385

RESUMO

European badgers, Meles meles, are group-living in the UK, and demarcate their ranges with shared latrines. As carnivores, badgers possess paired anal glands, but olfactory information on the content of badger anal gland secretion (AGS) is largely uninvestigated. Here, we examined the volatile organic compounds (VOCs) of AGS samples from 57 free-living badgers using solid-phase microextraction (SPME) and gas chromatography-mass spectrometry. AGS was rich in alkanes (C7-C15, 14.3% of identified compounds), aldehydes (C5-C14, 9.7%), phenols (C6-C15, 9.5%), alcohols (C5-C10, 7.3%), aromatic hydrocarbons (C6-C13, 6.8%), ketones (C6-C13, 6.3%) and carboxylic acids (C3-C12, 5.6%) and contained a variety of esters, sulfurous and nitrogenous compounds, and ethers. The number of VOCs per profile ranged from 20 to 111 (mean = 65.4; ± 22.7 SD), but no compound was unique for any of the biological categories. After normalization of the raw data using Probabilistic Quotient Normalization, we produced a resemblance matrix by calculating the Euclidian distances between all sample pairs. PERMANOVA revealed that AGS composition differs between social groups, and concentration and complexity in terms of number of measurable VOCs varies between seasons and years. AGS VOC profiles encode individual identity, sex and vary with female reproductive state, indicating an important function in intraspecific communication. Because AGS is excreted together with fecal deposits, we conclude that chemical complexity of AGS enables particularly latrine-using species, such as badgers, to advertise more complex individual-specific information than in feces alone.


Assuntos
Canal Anal/química , Mustelidae/fisiologia , Feromônios/química , Alcanos/química , Alcanos/isolamento & purificação , Alcanos/farmacologia , Canal Anal/metabolismo , Comunicação Animal , Animais , Comportamento Animal/efeitos dos fármacos , Feminino , Cromatografia Gasosa-Espectrometria de Massas , Feromônios/isolamento & purificação , Feromônios/farmacologia , Estações do Ano , Microextração em Fase Sólida , Compostos Orgânicos Voláteis/química , Compostos Orgânicos Voláteis/isolamento & purificação , Compostos Orgânicos Voláteis/farmacologia
19.
Chem Biodivers ; 16(12): e1900506, 2019 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-31633273

RESUMO

Perfumes have always been products of great importance, mainly composed of natural, valuable and vegetal raw materials. Today, some of them have completely disappeared in perfumery, even though they are part of our cultural heritage and were commonly used in the past. Balm of Judea is one of the most noble, rare and fascinating ingredient long used in perfumery and medicine, that is missing today. After years of research, we collected a resin and an essential oil (steam distillation of fresh aerial parts) from Commiphora gileadensis (L.) C.Chr. native from Saudi Arabia and cultivated in Israel. The aims of this study were to i) identify the main reasons of the loss of the balm of Judea, ii) characterize the volatile composition of the resin and the essential oil and iii) evaluate their olfactory profile and assess their biological activity. Eighty-three compounds were identified in the resin, by a combination of GC-MS and GC/FID techniques, using direct injection and HS-SPME. α-Pinene (24.0 %), sabinene (43.8 %), ß-pinene (6.3 %) and cymene (3.6 %) were the main identified compounds, giving an intense, terpenic and lemony smell to the resin. Anti-inflammatory, wound-healing and whitening activities were highlighted. Sabinene (22.7 %), terpinen-4-ol (18.7 %), α-pinene (14.4 %) and cymene (13.6 %) were identified as the main components of the essential oil, giving a spicy, woody and lemony fragrance. Anti-inflammatory and whitening activities were emphasized.


Assuntos
Commiphora/química , Óleos Voláteis/química , Anti-Inflamatórios/química , Anti-Inflamatórios/isolamento & purificação , Commiphora/metabolismo , Cromatografia Gasosa-Espectrometria de Massas , Odorantes/análise , Óleos Voláteis/isolamento & purificação , Componentes Aéreos da Planta/química , Componentes Aéreos da Planta/metabolismo , Resinas Vegetais/química , Resinas Vegetais/metabolismo , Microextração em Fase Sólida
20.
Anal Bioanal Chem ; 411(28): 7551-7562, 2019 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-31641822

RESUMO

In this work, a straightforward analytical approach based on headspace solid-phase microextraction coupled with gas chromatography-mass spectrometry was developed for the analysis of salivary volatile organic compounds without any prior derivatization step. With a sample volume of 500 µL, optimal conditions were achieved by allowing the sample to equilibrate for 10 min at 50 °C and then extracting the samples for 10 min at the same temperature, using a carboxen/polydimethylsiloxane fibre. The method allowed the simultaneous identification and quantification of 20 compounds in sample headspace, including short-chain fatty acids and their derivatives which are commonly analysed after analyte derivatization. The proof of applicability of the methodology was performed with a case study regarding the analysis of the dynamics of volatile metabolites in saliva of a single subject undergoing 5-day treatment with rifaximin antibiotic. Non-stimulated saliva samples were collected over 3 weeks from a nominally healthy volunteer before, during, and after antibiotic treatment. The variations of some metabolites, known to be produced by the microbiota and by bacteria that are susceptible to antibiotics, suggest that the study of the dynamics of salivary metabolites can be an excellent indirect method for analysing the gut microbiota. This approach is novel from an analytical standpoint, and it encourages further studies combining saliva metabolite profiles and gut microbiota dynamics. Graphical abstract.


Assuntos
Cromatografia Gasosa-Espectrometria de Massas/métodos , Microbioma Gastrointestinal , Saliva/química , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise , Antibacterianos/administração & dosagem , Humanos , Limite de Detecção , Reprodutibilidade dos Testes
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