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1.
Food Chem ; 302: 125290, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31404873

RESUMO

In our daily lives, we consume foods that have been transported, stored, prepared, cooked, or otherwise processed by ourselves or others. Food storage and preparation have drastic effects on the chemical composition of foods. Untargeted mass spectrometry analysis of food samples has the potential to increase our chemical understanding of these processes by detecting a broad spectrum of chemicals. We performed a time-based analysis of the chemical changes in foods during common preparations, such as fermentation, brewing, and ripening, using untargeted mass spectrometry and molecular networking. The data analysis workflow presented implements an approach to study changes in food chemistry that can reveal global alterations in chemical profiles, identify changes in abundance, as well as identify specific chemicals and their transformation products. The data generated in this study are publicly available, enabling the replication and re-analysis of these data in isolation, and serve as a baseline dataset for future investigations.


Assuntos
Bebidas/análise , Análise de Alimentos , Manipulação de Alimentos , Espectrometria de Massas , Metabolômica , Fermentação , Fluxo de Trabalho
2.
Food Chem ; 302: 125331, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31404867

RESUMO

Adulteration of the high-value silver pomfret (Pampus argenteus) is a serious problem worldwide, necessitating accurate identification and quantification of the species. In this study, optimisation of the digital droplet PCR (ddPCR) assay for the identification and quantification of the silver pomfret was carried out. The primer and probe concentrations, melting temperature, and PCR cycle number were optimised by combining single-factor experiments with an orthogonal experimental design. The absolute limits of detection and quantification of the ddPCR were 2copies/µl and 21 copies/µl, respectively. Its sensitivity was 0.1% for meat mixtures and 0.5% for DNA mixtures. The ddPCR was 156 times more sensitive than the real-time PCR, although both methods had similar specificities. However, the overall time needed to complete the ddPCR method was twice that of the real-time PCR. Notwithstanding, the ddPCR methodology established in this study can be a valuable tool for addressing species adulteration issues.


Assuntos
Produtos Pesqueiros/análise , Análise de Alimentos/métodos , Perciformes/genética , Reação em Cadeia da Polimerase/métodos , Animais , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
3.
Food Chem ; 302: 125329, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31404874

RESUMO

Olive oil is an essential diet component in all Mediterranean countries having a considerable impact on the local economies, which are producing almost 90% of the world production. Therefore, the quality assessment of olive oil in terms of its acidity and its authentication in terms of PDO (Protected Designation of Origin) and PGI (Protected Geographical Indications) characterizations are nowadays necessary and of great importance for the market of olive oil and the related economic activities. In the present work, Laser Induced Breakdown Spectroscopy (LIBS) is used assisted by machine learning algorithms for retrieving of the information contained in the LIBS spectra to provide a simple, reliable, and ultrafast methodology for olive oils classification in terms of the degree of acidity and geographical origin. The combination of LIBS technique with machine learning statistical analysis approaches constitute a very powerful tool for the fast, in-situ and remote quality control of olive oil.


Assuntos
Análise de Alimentos/métodos , Aprendizado de Máquina , Azeite de Oliva/análise , Processamento de Sinais Assistido por Computador , Análise Espectral/métodos , Algoritmos , Lasers , Azeite de Oliva/química
4.
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
5.
Food Chem ; 302: 125340, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31419775

RESUMO

In this study, 83 wines representating four commercial categories: "Argentinean Malbec", "Brazilian Merlot", "Uruguayan Tannat" and "Chilean Carménère" were analyzed according to their phenolic and volatile compounds. The objective was to identify the chemical compounds that would typify each category. From approximately about 600 peaks obtained by chromatographic techniques, 169 were identified and 53 of them were selected for multivariate statistical analysis. Chilean Carménère was the best discriminated group by the methods applied in our study, followed by Argentinean Malbec. Brazilian Merlot mixed mainly with some Carménère, whileTannat mixed with all wines categories, especially Malbec. In general, Chilean Carménère wines can be characterized by a bluish color, higher amounts of sulphur dioxide, higher content of octanoic acid, isobutanol, ethyl isoamyl succinate and catechin and a smaller amount of quercetin. These data can contribute for further process of authenticity or typification of South American red wines.


Assuntos
Análise de Alimentos/estatística & dados numéricos , Fenóis/análise , Compostos Orgânicos Voláteis/análise , Vinho/análise , Butanóis/análise , Caprilatos/análise , Catequina/análise , Análise de Alimentos/métodos , Cromatografia Gasosa-Espectrometria de Massas/métodos , Cromatografia Gasosa-Espectrometria de Massas/estatística & dados numéricos , Análise Multivariada , Quercetina/análise , América do Sul , Dióxido de Enxofre/análise , Vinho/classificação
6.
Food Chem ; 303: 125369, 2020 Jan 15.
Artigo em Inglês | MEDLINE | ID: mdl-31442902

RESUMO

A well-designed yolk-shell Fe3O4@graphitic carbon (YS-Fe3O4@GC) submicroboxes with a tunable internal cavity were constructed by one-step pyrolysis strategy followed by partially etching, in which the Fe3O4 magnetic core was well confined in compartment of GC submicroboxes. The suitable internal cavity, graphitic carbon shell and large specific surface area, play great roles in improving mass transfer of analytes. Compared to its core-shell structure, the YS-Fe3O4@GC submicroboxes as dispersive magnetic solid-phase extraction (d-MSPE) materials exhibited superior enrichment performance for sulfonamides (SAs). Thus, it was applied to sensitive/simultaneous detection of trace SAs in milk and meat samples, combing with high performance liquid chromatography (HPLC). Under optimized conditions, limits of detection (LODs, 0.11-0.25 µg L-1 for milk and 0.46-2.24 µg kg-1 for meat) and recoveries (77.2-118.0%) were obtained. This work not only offers a facile strategy for the tunable fabrication of yolk-shell architecture, but also successfully affords its exploration as d-MSPE materials.


Assuntos
Análise de Alimentos , Grafite/química , Extração em Fase Sólida/métodos , Sulfonamidas/isolamento & purificação , Animais , Cromatografia Líquida de Alta Pressão , Compostos de Ferro/química , Limite de Detecção , Magnetismo , Carne/análise , Leite/química , Sulfonamidas/análise
7.
Food Chem ; 302: 125371, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31437711

RESUMO

Dietary selenium deficiency is recognized as a global problem. Pork is the most widely consumed meat throughout the world and an important source of selenium for humans. In this study, a reliable approach was developed for analyzing selenium and its speciation in the muscles of pigs after different selenium treatments. The selenium source deposition efficiency was ranked as: selenomethionine > methylselenocysteine > selenite, and the muscle selenium content had a dose effect with selenomethionine supplementation. In total, four species of selenium were detected in the muscles of pigs and the distributions of these selenium species were greatly affected by the dietary selenium supplementation forms and levels. Selenomethionine (>70% of total selenium) and selenocystine (>11%) were the major selenium species, followed by methylselenocysteine and selenourea. Therefore, selenium-enriched pork produced from selenomethionine is a good source for improving human dietary selenium intake.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Espectrometria de Massas/métodos , Músculo Esquelético/química , Compostos de Selênio/farmacologia , Selênio/análise , Animais , Cistina/análogos & derivados , Cistina/análise , Suplementos Nutricionais , Análise de Alimentos/métodos , Masculino , Músculo Esquelético/efeitos dos fármacos , Compostos Organosselênicos/análise , Reprodutibilidade dos Testes , Ácido Selenioso/farmacologia , Compostos de Selênio/análise , Selenocisteína/análogos & derivados , Selenocisteína/farmacologia , Selenometionina/análise , Selenometionina/farmacologia , Suínos , Ureia/análogos & derivados , Ureia/análise
8.
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
9.
Food Chem ; 302: 125359, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442702

RESUMO

A simple and rapid sensing strategy was proposed for chloramphenicol (CAP) detection based on structure-switching signaling aptamers. In this protocol, the aptamer can bind to both the fluorophore (FAM)-labeled complementary strand and the quencher (BHQ1)-labeled complementary strand, thus leading to the effective quenching of FAM fluorescence by BHQ1. However, when CAP is present, the structure switch is reversed because the aptamer recognizes CAP, resulting in fluorescence recovery. Such a fluorescence-sensing platform can monitor CAP within a good linear range (1-100 ng/mL), with a detection limit of 0.70 ng/mL. Cross-reactivity with other common antibiotics is negligible, indicating the excellent selectivity of the strategy. Moreover, as the aptamers are not modified, this method is simple and low-cost. The present work reveals a new direction for detecting CAP or other target compounds without prior knowledge of the secondary or tertiary structures of the aptamer.


Assuntos
Aptâmeros de Nucleotídeos/química , Cloranfenicol/análise , Transferência Ressonante de Energia de Fluorescência/métodos , Análise de Alimentos/métodos , Animais , Antibacterianos/análise , Aptâmeros de Nucleotídeos/metabolismo , Corantes Fluorescentes/química , Contaminação de Alimentos/análise , Limite de Detecção , Leite/química , Sensibilidade e Especificidade
10.
Food Chem ; 302: 125365, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442703

RESUMO

Retention of labile vitamins such as thiamine (vitamin B1) in NASA spaceflight foods intended for extended-duration missions is critical for the health of the crew. In this study, the degradation kinetics of thiamine in three NASA spaceflight foods (brown rice, split pea soup, BBQ beef brisket) during storage was determined for the first time, using an interactive isothermal model developed by our group. Results showed that brown rice and split pea soup demonstrated resistance to thiamine degradation, while thiamine in beef brisket was less stable. Model-predicted thiamine retention in brown rice stored at 20 °C for 720 days was 55% of the original thiamine content after thermal processing, 42% for split pea soup, and 3% for beef brisket. Water activity, moisture content, and pH differences did not sufficiently explain the variation in the degradation kinetics of thiamine among these foods.


Assuntos
Armazenamento de Alimentos , Alimentos , Tiamina/metabolismo , Análise de Alimentos/métodos , Concentração de Íons de Hidrogênio , Cinética , Oryza , Carne Vermelha , Voo Espacial , Temperatura Ambiente , Tiamina/análise , Estados Unidos , United States National Aeronautics and Space Administration , Água/química
11.
Food Chem ; 302: 125373, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31442706

RESUMO

The aim of this work was to investigate and compare the phenolic profile of 15 wild growing blackthorn (Prunus spinosa L.) genotypes from the slopes of Fruska Gora mountain in north Serbia. Their effect in inhibiting i) α-amylase and α-glucosidase activities and ii) colorectal cancer cell line (HT29) growth was also studied. Blackthorn fruit extracts exhibited high phenolic content being enrich in anthocyanins. Principal component analysis was used to correlate the bioactive response with phenolic composition. It was found that derivatives quercetin and anthocyanin peonidin are the major contributors of the inhibition of carbohydrates hydrolyzing enzymes as well as with the antiproliferative effect of blackthorn. Among all samples, the genotype from Beska locality showed the higher capacity in inhibiting alpha-amylase, alpha-glucosidase and HT29 cell growth. Because of high anthocyanin content and higher bioactive response, these genotypes could be recommended for the further cultivation and investigation.


Assuntos
Polifenóis/análise , Prunus/química , Prunus/genética , Antocianinas/análise , Antineoplásicos Fitogênicos/química , Antineoplásicos Fitogênicos/farmacologia , Antioxidantes/análise , Ácido Clorogênico/análogos & derivados , Ácido Clorogênico/análise , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/estatística & dados numéricos , Frutas/química , Genótipo , Inibidores de Glicosídeo Hidrolases/química , Inibidores de Glicosídeo Hidrolases/farmacologia , Células HT29 , Humanos , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Polifenóis/farmacologia , Análise de Componente Principal , Quercetina/análise , Ácido Quínico/análogos & derivados , Ácido Quínico/análise , Sérvia , alfa-Amilases/antagonistas & inibidores
12.
Food Chem ; 302: 125345, 2020 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-31445377

RESUMO

This paper compares the results of standard chemical analytical processes and electrochemical impedance spectroscopy (EIS) in the characterization of different beverages, namely ground coffee, soluble coffee, coffee substitutes, barley, cow milk, vegetable drinks, tea, plant infusions and plant mixtures. For the two approaches, the similarities between the experimental data are assessed by means of the Euclidean and Canberra distances. The resulting information is processed by means of the multidimensional scaling (MDS) clustering and visualization algorithm. The results of the chemical analytical processes and EIS reveal identical clusters for the two adopted distances. Furthermore, the robustness of the experimental and computational scheme are assessed by means of the Procrustes technique. The results confirm the effectiveness of combining the EIS and MDS.


Assuntos
Bebidas/análise , Visualização de Dados , Espectroscopia Dielétrica/métodos , Algoritmos , Animais , Técnicas de Química Analítica/métodos , Análise por Conglomerados , Café/química , Espectroscopia Dielétrica/estatística & dados numéricos , Análise de Alimentos/métodos , Análise de Alimentos/estatística & dados numéricos , Leite/química , Processamento de Sinais Assistido por Computador , Chá/química
13.
Se Pu ; 37(11): 1173-1178, 2019 Nov 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642269

RESUMO

A rapid screening method was developed to determine sibutramine and five derivatives in health food by high performance liquid chromatography-quadrupole/electrostatic orbitrap high-resolution mass spectrometry (HPLC-Q/Orbitrap HRMS). The sample was extracted with methanol via ultrasonic-assisted extraction coupled with high-speed centrifugation. Separation was performed on a Hypersil Gold column (100 mm×2.1 mm, 3 µm) by gradient elution with methanol/water (containing 0.15%(v/v) formic acid) as the mobile phase. The positive full mass scan/date-dependent MS2 (Full MS/dd-MS2) mode was used during MS detection, and quantification was achieved by resolution of the precursor mass. The analytes in the sample were separated, and accurate mass and MS2 fragment ions were simultaneously attained within 8 min. The results indicated that the obtained mass accuracy errors of the six analytes were less than 1×10-6. Good linearities were obtained in the range of 0.5-20.0 µg/L, and all correlation coefficients were higher than 0.999. The limits of quantification were 25 µg/kg and the recoveries were in the range of 93.5%-103.5% with relative standard deviations of 1.5%-7.7%. This simple-pretreatment, rapid, accurate, high-sensitivity, and high-selectivity method can be used in the rapid screening and quantitative analysis of sibutramine and its derivatives in health food.


Assuntos
Ciclobutanos/análise , Análise de Alimentos/métodos , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas , Eletricidade Estática
14.
Se Pu ; 37(10): 1105-1111, 2019 Oct 08.
Artigo em Chinês | MEDLINE | ID: mdl-31642290

RESUMO

An analytical method by ultra-high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) was developed for the simultaneous determination of the two types of nutrients, viz. gingerol-related compounds and curcuminoids in ginger, including 6-gingerol, 8-gingerol, 10-gingerol, 6-shogaol, 8-shogaol, 10-shogaol, tetrahydrocurcumin, curcumin, demethoxycurcumin and bisdemethoxycurcumin. The 10 target compounds were separated on a ZORBAX RRHD Eclipse Plus C18 column (100 mm×2.1 mm, 1.8 µm) using gradient elution with 0.1% (v/v) formic acid aqueous solution and methanol containing 0.1% (v/v) formic acid as the mobile phases. Qualitative confirmation and quantitative analysis of the target compounds were performed using an electrospray ionization (ESI) source in the positive ion and multiple reaction monitoring (MRM) modes. The linear correlation coefficients (r) of the 10 nutrients were ≥ 0.9995. The limits of quantification were 0.10-7.71 µg/L. The average spiked recoveries of the samples at the three levels were 82.8%-115.3%, the relative standard deviations (RSDs) were 0.58%-11.49%. The results showed that all the 10 nutrients in ginger were detected, and the content of 6-gingerol was the highest at 373.35-702.48 mg/kg. This method is convenient, rapid, accurate and reliable, and is suitable for the analysis of gingerol-related and curcuminoids in ginger. It provides a technical means for the quality identification and control of ginger.


Assuntos
Análise de Alimentos/métodos , Gengibre/química , Nutrientes/análise , Compostos Fitoquímicos/análise , Cromatografia Líquida de Alta Pressão , Espectrometria de Massas em Tandem
15.
J Agric Food Chem ; 67(39): 10968-10976, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31487165

RESUMO

Food contact materials (FCMs) may release their chemical components into food and thus raise safety concerns. This paper attempted to study the presence of four major groups of FCM-related endocrine disruptors in fatty food: dialkyl phthalates, bisphenols, printing ink photoinitiators, and polyfluoroalkyl substances. All 41 target compounds were analyzed simultaneously by means of liquid chromatography coupled to tandem mass spectrometry. The sample preparation was significantly streamlined to reduce analysis costs by employing acetonitrile extraction, extract modification by water, and refrigeration at 5 °C. The new method was validated and applied to 60 real samples, including edible oils, butter, and chocolate, where 16 target compounds were measured at levels ≤13000 ng/g. The study also described the blank level increase and sensitivity loss caused by impurities present in the HPLC methanol solvent.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Espectrometria de Massas em Tandem/métodos , Compostos Benzidrílicos/análise , Fenóis/análise , Ácidos Ftálicos/análise
16.
Anal Chim Acta ; 1083: 1-18, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31493799

RESUMO

Modern food analysis is directed to the characterization of as many components as possible in food and food-related materials. The use of -omics technologies within a Foodomics approach requires the use of high throughput analytical techniques able to offer increased resolving power and capability to separate a high number of compounds. From this perspective, two-dimensional liquid chromatography has the potential to unravel very complex food matrices, providing with high resolving power and enhanced identification potential, particularly when coupled to mass spectrometry. This review presents an overview including the most notable two-dimensional liquid chromatography applications developed in the last ten years to study food safety, food quality and the relationship between health and food as well as for the characterization of particular groups of food components within a Foodomics perspective. Moreover, the latest developments and advances, limitations, future evolution and needs related to the use of this technique are critically discussed and commented.


Assuntos
Cromatografia Líquida/métodos , Análise de Alimentos/métodos , Animais , Contaminação de Alimentos/análise , Qualidade dos Alimentos , Humanos , Proteômica/métodos
17.
Anal Chim Acta ; 1083: 101-109, 2019 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-31493800

RESUMO

In this work, a facile ratiometric electrochemical aptasensor was developed towards sensitive and selective detection of vanillin, based on Ketjen black/ferrocene dual-doped zeolite-like MOFs (Fc-KB/ZIF-8) and electrodeposited gold nanoparticles (AuNPs) coupling with DNA aptamer. Fc-KB/ZIF-8 composites were prepared via one-pot solvothermal reaction and drop-coated on glassy carbon electrode (GCE) surface to form Fc-KB/ZIF-8@GCE. AuNPs were in-situ electro-deposited on the modified GCE. 5'-SH terminated aptamer of vanillin was combined with AuNPs via Au-S coupling to form aptamer-AuNPs/Fc-KB/ZIF-8@GCE as a new sensing platform. Under optimal conditions, electrochemical (square wave voltammetry) curves of this sensing platform were measured in electrolyte solutions containing vanillin. With increase of vanillin concentration (Cvan), vanillin had an increased peak current intensity (Ivan, as response signal). Fc doped into ZIF-8 had slight changes in its peak current intensity (IFc, as reference signal). There is a well plotting linear relationship between Ivan/IFc and the logarithm of Cvan ranging from 10 nM to 0.2 mM, with a low limit of detection of 3 nM. The aptamer-AuNPs/Fc-KB/ZIF-8@GCE was applied as a ratiometric electrochemical aptasensor of vanillin. This aptasensor had sensitive and selective electrochemical signal responses on vanillin, over potential interferents. This aptasensor enabled vanillin detection in real food samples, showing high detection performance. Experimental results testified that this aptasensor had high reliability and practicability for vanillin determination in real samples.


Assuntos
Aptâmeros de Nucleotídeos/química , Benzaldeídos/análise , DNA/química , Nanopartículas Metálicas/química , Estruturas Metalorgânicas/química , Benzaldeídos/química , Doces/análise , Carbono/química , Chocolate/análise , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Compostos Ferrosos/química , Análise de Alimentos/métodos , Ouro/química , Limite de Detecção , Metalocenos/química
18.
Artigo em Inglês | MEDLINE | ID: mdl-31479386

RESUMO

A rapid method for quantitative caffeine analysis in carbonated and non-carbonated beverages and liquid dietary supplement products was developed based on the direct sample introduction technique of laser diode thermal desorption atmospheric pressure chemical ionisation with tandem mass spectrometry (LDTD-MS/MS). Product samples were diluted with a mixture of methanol, water, and d3-caffeine internal standard. Sample aliquots were filtered, spotted on a metal-lined LDTD microtitre plate, dried, and thermally desorbed for subsequent ionisation and analysis by MS/MS analysis. Each sample required a 6 s desorption, and sample-to-sample analysis time of less than 30 s per sample. Caffeine yielded a linear calibration curve over the range 0.5-100 µg mL-1 (R2 > 0.995). Caffeine recoveries from fortified samples ranged from 97% to 107% with <5% RSD. The caffeine determination was not affected by matrix interferences despite the large range of ingredients, vitamins, sweeteners, extracts, and additives present in the products tested, even though LDTD-MS/MS is a whole-sample desorption technique with no separation of matrix background. The method detection limit was below 0.12 µg mL-1. The method was applied to 33 caffeinated products and LDTD-MS/MS quantitative results closely correlated (R2 > 0.998) with the regulatory standard HPLC-UV method (AOAC Official Method 979.08).


Assuntos
Bebidas/análise , Cafeína/análise , Análise de Alimentos/métodos , Lasers , Análise de Alimentos/instrumentação , Espectrometria de Massas em Tandem
19.
Artigo em Inglês | MEDLINE | ID: mdl-31490741

RESUMO

1-Phenylthiosemicarbazide bonded modified silica gel (PTC-SG) was synthesised and characterised by FTIR, SEM and elemental analysis for a novel separation/preconcentration of multiple elements based on solid phase extraction. The analytical parameters including pH of solutions, amounts of PTC-SG, flow rates of sample, eluent type and sample volume were optimised. The adsorption capacities of PTC-SG were found to be 7.9, 6.4, 6.3, 8.3, 7.2, 8.9 and 6.6 mg/g for Cu(II), Cd(II), Pb(II), Co(II), Cr(III), Ni(II) and Mn(II), respectively. The limit of detection (LOD) was calculated as 3x the standard deviation(s) of the reagent blank (k = 3, N = 21) and the LOD values were obtained to be 0.98 µg L-1 (Cu), 0.65 µg L-1 (Cd), 0.57 µg L-1 (Pb), 1.12 µg L-1 (Co), 1.82 µL-1 (Cr), 1.67 µg L-1 (Ni) and 0.55 µg L-1 (Mn). Certified reference materials were used to test the validation of the present method. The new solid phase extraction method was successfully applied to determination of the amount of multiple elements in food and beverage samples.


Assuntos
Bebidas/análise , Análise de Alimentos , Contaminação de Alimentos/análise , Metais Pesados/análise , Sílica Gel/química , Tiossemicarbazonas/química , Agaricales/química , Animais , Cromatografia Líquida , Peixes , Mel/análise , Oryza/química , Sílica Gel/síntese química , Espectrometria de Massas em Tandem , Chá/química
20.
Artigo em Inglês | MEDLINE | ID: mdl-31535952

RESUMO

In this study, we propose an improved analytical method for the multiresidue analysis of captan (plus its metabolite, tetrahydrophthalimide), folpet (plus its metabolite, phthalimide), captafol, and iprodione in cereals using liquid chromatography tandem mass spectrometry (LC-MS/MS). As captan, captafol, and folpet are easily degraded during homogenisation and extraction, samples were comminuted with liquid nitrogen, and both QuEChERS and ethyl acetate-based extraction workflows provided a satisfactory method performance. The optimised LC-MS/MS procedure with electrospray ionisation did not degrade these compounds, and offered sufficient method selectivity by resolving and minimising co-eluting matrix-derived interferences. The method also resolved the problem of non-specific mass spectra that these compounds usually produce on GC-MS analysis involving electron ionisation. The method performance was satisfactory for all 6 compounds at 0.01 mg kg-1 and higher levels of fortification, and validated as per the SANTE/11813/2017 guidelines of analytical quality control in a wide range of cereals including rice, wheat, sorghum, and corn. The method provides special advantage of simultaneous analysis of captan, and folpet along with their metabolites (tetrahydrophthalimide, and phthalimide, respectively) in combination with captafol, and iprodione in a single chromatographic run. Although iprodione is known to degrade to 3,5-dichloroaniline, since this metabolite is not a part of the residue definition, it was not included in the scope of this method. As the method demonstrates satisfactory selectivity, sensitivity, accuracy, precision, and robustness in a wide range of cereal matrices, it is recommended for regulatory testing of these compounds in cereals.


Assuntos
Aminoimidazol Carboxamida/análogos & derivados , Captana/análogos & derivados , Captana/análise , Cicloexenos/análise , Contaminação de Alimentos/análise , Hidantoínas/análise , Resíduos de Praguicidas/análise , Ftalimidas/análise , Aminoimidazol Carboxamida/análise , Cromatografia Líquida , Grão Comestível/química , Análise de Alimentos , Espectrometria de Massas em Tandem
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