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1.
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
2.
Food Chem ; 300: 125173, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31319335

RESUMO

The administration of anabolic agents in farm animals to improve meat production has been prohibited in EU, due to the potential risks to human health. Meat quality was investigated to detect the effects of illegal administration of dexamethasone or prednisolone or 17ß-estradiol on Charolais bulls. Three groups of 6 bulls were treated and 12 bulls were the control. Meat quality parameters were measured on live animals, carcasses and on samples of Longissimus thoracis and multivariate statistical data analysis was applied. In Charolais bulls, these parameters were affected by growth promoter administration and the multivariate canonical discriminant analysis was able to distinguish between treated and untreated animals mainly due to three electronic nose's parameters, 24 h carcass temperature and drip loss. Therefore, meat quality control and the multivariate analysis could be useful as a first screening to address targeted controls on farms suspected of illicit use of growth promoters.


Assuntos
Análise de Alimentos/métodos , Substâncias de Crescimento/farmacologia , Carne , Músculo Esquelético/efeitos dos fármacos , Músculo Esquelético/crescimento & desenvolvimento , Animais , Bovinos , Dexametasona/farmacologia , Análise Discriminante , Nariz Eletrônico , Estradiol/farmacologia , Fazendas , Análise de Alimentos/instrumentação , Análise de Alimentos/estatística & dados numéricos , Qualidade dos Alimentos , Masculino , Carne/análise , Prednisolona/farmacologia
3.
Food Chem ; 300: 125179, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325751

RESUMO

In this work, a disposable and portable aptasensor for the fast and sensitive detection of oxytetracycline (OTC) using gold nanoparticles (AuNPs)/carboxylated multi-walled carbon nanotubes (cMWCNTs)@thionine connecting complementary strand of aptamer (cDNA) as signal tags was constructed. The substrate electrode of the aptasensor was thin film gold electrode (TFGE), which have the advantages of portable and uniform performance. In the presence of OTC, OTC competed with cDNA to combine with aptamer. The bioconjugate (AuNPs/cMWCNTs/cDNA@thionine) was released from the TFGE. Thus, the electrochemical signal declined. Under optimized conditions, the aptasensor exhibited good stability, high selectivity and high sensitivity. Furthermore, the developed electrochemical aptamer-based TFGE had a wide dynamic range of 1 × 10-13-1 × 10-5 g mL-1 for target OTC with a low detection limit of 3.1 × 10-14 g mL-1 and was successfully used for the determination of OTC in chicken sample.


Assuntos
Técnicas Eletroquímicas/métodos , Eletrodos , Contaminação de Alimentos/análise , Oxitetraciclina/análise , Produtos Avícolas/análise , Animais , Antibacterianos/análise , Aptâmeros de Nucleotídeos , Galinhas , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Nanotubos de Carbono/química , Sensibilidade e Especificidade
4.
Food Chem ; 300: 125178, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31326677

RESUMO

In this work, a sensitive and stable ZrO2-Cu(I) nanosphere mesoporous material modified non-enzymatic glucose sensor has been developed through simple, low cost chemistry. ZrO2-Cu(I) material was obtained by controlled co-precipitation method under ultra dilution conditions. Cyclic voltammetric tests were performed in order to evaluate the electrocatalytic activity ZrO2-Cu(I) modified electrode. The modified electrode showed high sensitivity, wide linear range and very low detection limit of 0.25 mM, this indicates that the modified sensor is competent with that reported earlier. Spherical morphology of the active material, alkaline environment and presence of +1 copper have significantly enhanced the electro-catalytic oxidation of glucose on carbon paste platform. Also, the fabricated electrode showed excellent anti-interference nature. Electro-catalytic oxidation of glucose was demonstrated in real raw unpurified orange juice, this shows the selective electrocatalytic activity of the ZrO2-Cu(I) nanosphere material towards glucose even in the presence of interferrants.


Assuntos
Citrus sinensis/química , Técnicas Eletroquímicas/instrumentação , Técnicas Eletroquímicas/métodos , Eletrodos , Glucose/análise , Carbono/química , Catálise , Cobre/química , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Sucos de Frutas e Vegetais/análise , Glucose/química , Limite de Detecção , Nanosferas/química , Oxirredução , Zircônio/química
5.
Food Chem ; 300: 125203, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31330367

RESUMO

Microwave (MW) radiation was applied to perform the separation of triacylglycerols (TGs) in oil samples. The novelty of the work lies in the application of MW radiation to assist the separation of several non-polar compounds employing a totally organic mobile phase. Once the influence of the evaporative light scattering detector (ELSD) variables on the sensitivity was optimized, the TGs separation was compared conditioning the column with either a conventional HPLC or a MW oven. Contrary to previous applications in which the mobile phase contained water, the improvement in sensitivity using MW was not as significant in comparison with conventional heating but it allowed a shortening in the retention times of several TGs in about 50% respect elution at room temperature. The method was finally applied for the quantification of most common TGs in almond, tiger nut, and argan oil.


Assuntos
Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos/métodos , Óleos Vegetais/química , Triglicerídeos/análise , Triglicerídeos/isolamento & purificação , Cromatografia Líquida de Alta Pressão/instrumentação , Análise de Alimentos/instrumentação , Micro-Ondas , Óleos Vegetais/análise , Espalhamento de Radiação , Temperatura Ambiente , Água
6.
Food Chem ; 300: 125176, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31351258

RESUMO

Mycotoxins are toxic metabolites produced by fungi or molds, which may cause serious harm to human health through polluted cereal foods. In order to measure the typical mycotoxin contaminations in wheat and corn, a surface plasmon resonance (SPR) method was established using SPR sensor chip that was fabricated based on self-assembled monolayer. The minimum detection limit of aflatoxin B1, ochratoxin A, zearalenone and deoxynivalenol were identified as 0.59 ng/mL, 1.27 ng/mL, 7.07 ng/mL and 3.26 ng/mL, respectively. The cross-reactivity for all four mycotoxins were demonstrated to be low. Moreover, the test data were compared with HPLC-MS/MS confirmatory analysis results and good agreement was found between them. In conclusion, the SPR method for simultaneously detecting four mycotoxins has been developed with high sensitivity, good linearity and specificity, which can meet the detection requirements of cereal foods.


Assuntos
Micotoxinas/análise , Ressonância de Plasmônio de Superfície/métodos , Triticum/química , Zea mays/química , Aflatoxina B1/análise , Aflatoxina B1/imunologia , Cromatografia Líquida de Alta Pressão , Reações Cruzadas , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Hidrazonas/química , Limite de Detecção , Micotoxinas/imunologia , Ocratoxinas/análise , Ocratoxinas/imunologia , Sensibilidade e Especificidade , Ressonância de Plasmônio de Superfície/instrumentação , Espectrometria de Massas em Tandem , Tricotecenos/análise , Tricotecenos/imunologia , Triticum/microbiologia , Zea mays/microbiologia , Zearalenona/análise , Zearalenona/imunologia
7.
J Agric Food Chem ; 67(31): 8425-8430, 2019 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-31322874

RESUMO

In recent years, non-targeted methods have been a popular "buzz" phrase in food fraud detection. Using analytical instrumentation techniques, non-targeted methods have been developed and applied in many food and agricultural situations. However, confusion and misstatements remain regarding how the methods are used. This perspective will discuss the definitions related to non-targeted testing, the procedure of developing and validating methods, the techniques and data analysis, and opportunities and challenges regarding the use of this class of analytical methods. The perspective seeks to provide readers with the latest information regarding recent advances in the use of non-targeted methods.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Cromatografia Líquida/métodos , Eletroforese Capilar/métodos , Análise de Alimentos/instrumentação , Humanos , Espectroscopia de Ressonância Magnética/métodos , Espectrometria de Massas/métodos
8.
Food Chem ; 300: 125220, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31352288

RESUMO

Fruits and vegetables play an important role in human nutrition. Study of the contamination sources which result from farming activities is of importance. For this reason, a chitosan-graphene oxide nanocomposite film was prepared and implemented as the extractive phase in thin film microextraction of six organophosphate residues (OPPs) in the samples using high-performance liquid chromatography. The optimized method was validated and the limits of detection (0.7-1.2 µg l-1), limits of quantification (2.3-4.0 µg l-1) and linear dynamic range (2.0-1000.0 µg l-1) were obtained. Principal component analysis revealed clustering of the fruit and vegetable samples based on the selected (OPPs) into two groups of unwashed-unpeeled and peeled-washed. This mapping was further investigated using descriptive method of boxplot. Washing and peeling of the samples, reduced the presence of OPPs to half or one third of interquartile range found in the unpeeled and unwashed samples.


Assuntos
Contaminação de Alimentos/análise , Frutas/química , Organofosfatos/análise , Resíduos de Praguicidas/análise , Verduras/química , Cromatografia Líquida de Alta Pressão/métodos , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Análise de Alimentos/estatística & dados numéricos , Grafite/química , Limite de Detecção , Nanoestruturas/química , Óxidos/química , Análise de Componente Principal , Reprodutibilidade dos Testes , Microextração em Fase Sólida/instrumentação , Microextração em Fase Sólida/métodos
9.
Food Chem ; 300: 125189, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31325754

RESUMO

Since the intake of quercetin glucosides has healthy benefits, the analysis of quercetin glucosides in food is useful. The electrochemical determination of individual quercetin glucosides (quercetin-3-glucoside (Q3G), quercetin-4'-glucoside (Q4'G), and quercetin-3,4'-diglucoside (Q34'G)) in food is carried out. For the detection of quercetin glucosides, a long-length carbon nanotube electrode offers attractive properties such as well-defined current peaks, high sensitivity, and high reproducibility. Cyclic voltammetry (CV) demonstrates distinct and specific peak currents: the oxidation peaks at +0.37, +0.45, and +0.78 V are assigned to the catechol group in the B-ring of Q3G, the 3-hydroxy group in the C-ring of Q4'G, and the resorcinol group in the A-ring of both Q4'G and Q34'G, respectively. Currents, which are determined by CV, of individual quercetin glucosides at the peak potential are proportional to the concentrations of onion, apple peel, and tartary buckwheat, which show good agreement with those obtained by high-performance liquid chromatography.


Assuntos
Técnicas Eletroquímicas/instrumentação , Eletrodos , Análise de Alimentos/métodos , Glucosídeos/análise , Quercetina/análise , Técnicas Eletroquímicas/métodos , Fagopyrum/química , Análise de Alimentos/instrumentação , Malus/química , Nanotubos de Carbono , Cebolas/química , Oxirredução , Quercetina/análogos & derivados , Quercetina/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
10.
Food Chem ; 300: 125190, 2019 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-31330375

RESUMO

Technologies for monitoring meat spoilage are important to ensuring consumer safety. As dimethyl sulfide (DMS) is a reliable marker for meat freshness, sensitive and selective DMS sensors are of great interest. Herein, two trinuclear cyano-bridged bimetallic donor-acceptor ensembles, FeII(bpy)2(CN)2-[PtII(DMSO)Cl2]2 (1) and FeII(bpy)2(CN)2-[AuICl]2, were synthesized, and corresponding solid-supported sensors were fabricated to determine the effect of the acceptor metal (MA) on DMS detection. Changing MA from AuI to PtII improved the sensitivity and selectivity owing to changes in the relative thermodynamic stabilities of the complex and MA-DMS adduct. When applied to real meat samples, 1 exhibited a linear spectroscopic response to DMS, even in the presence of interfering compounds, with a method detection limit of 1.0 ppm. The total bacteria count and gas chromatography-mass spectrometry results revealed that the spectroscopic signal generated by 1 correlated with the microbial growth level and DMS concentration during meat spoilage.


Assuntos
Complexos de Coordenação/química , Análise de Alimentos/métodos , Carne/análise , Sulfetos/análise , Complexos de Coordenação/síntese química , Análise de Alimentos/instrumentação , Microbiologia de Alimentos , Ouro/química , Limite de Detecção , Carne/microbiologia , Platina/química , Sensibilidade e Especificidade , Compostos Orgânicos Voláteis/análise
11.
Food Chem ; 298: 124981, 2019 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-31260993

RESUMO

Development of an effective sensor for sensing glucose in commercially available "sugar free" food products is important as people are becoming diabetic health conscious. Although multi-walled carbon nanotubes (MWCNTs) possess interesting electrical properties, their hydrophobic nature limits their applications. Their hydrophilicity can be improved through modification. In the present study, Inulin, that was isolated from Allium sativum L. using hot water diffusion and incorporated with titanium dioxide (TiO2), was used for the modification of MWCNTs. The as-synthesized MWCNT-Inulin-TiO2 bio-nanocomposite immobilized with glucose oxidase (GOx) was incorporated into the carbon paste matrix and was utilized for the sensing of glucose in food products. Differential pulse voltammetric studies revealed that the fabricated electrode demonstrated good linear range (1.6 nM to 1 µM) and was sensitive to nanomolar concentrations of glucose with a very low limit of detection up to 0.82 nM and exhibited a long term stability of 150 days.


Assuntos
Eletrodos , Análise de Alimentos/métodos , Glucose Oxidase/química , Glucose/análise , Nanocompostos/química , Enzimas Imobilizadas/química , Análise de Alimentos/instrumentação , Alho/química , Glucose/química , Inulina/química , Limite de Detecção , Nanotubos de Carbono/química , Sensibilidade e Especificidade , Titânio/química
12.
Food Chem ; 299: 125144, 2019 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-31323440

RESUMO

Magnetic nanoparticles were synthesised to extract Sudan dyes from chilli powders. The adsorbents used were magnetic ferroferric oxide nanoparticles coated with polystyrene. The extraction procedures for Sudan dyes comprised liquid-solid extraction and magnetic solid phase extraction. The conditions were optimised to achieve efficient magnetic solid phase extraction, including extraction and desorption time, type and volume of the desorption solvent, and the mass of the adsorbents. Repeatability tests showed satisfactory recovery rates of 80.2-115.8%, with a relative standard deviation <3.8%. The results suggested that the proposed extraction method was effective and efficient to extract Sudan dyes from chilli powders. The extraction process was simpler compared with traditional approaches because the adsorbents can be rapidly removed from the sample matrix using a permanent magnet. The use of recyclable adsorbents decreased the cost greatly. Chilli powder samples collected from local markets in Singapore were tested using the proposed method under optimum conditions.


Assuntos
Capsicum/química , Corantes/análise , Contaminação de Alimentos/análise , Nanopartículas de Magnetita/química , Compostos Azo/análise , Fracionamento Químico/métodos , Cromatografia Líquida de Alta Pressão , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Pós/química , Reprodutibilidade dos Testes , Singapura , Extração em Fase Sólida/instrumentação , Extração em Fase Sólida/métodos
13.
Anal Bioanal Chem ; 411(25): 6603-6614, 2019 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-31317239

RESUMO

The topic of food analysis and safety has attracted increasing interest in recent decades owing to recent scandals concerning fraudulent activities (mislabeling, sophistication, adulteration, etc.) that can undermine human health. Among them, seafood fraud has probably the strongest relationship with food safety, an activity that goes beyond economic interests. This article explores the capabilities of an innovative instrumental setup, called the "iKnife," as a powerful tool in this specific research area, where until now genomics and proteomics have been the workhorses in analytical approaches. iKnife, which means "intelligent knife," is the name of a recent technology based on rapid evaporative ionization mass spectrometry (REIMS). REIMS is an emerging technique able to characterize different samples rapidly, affording a comprehensive profile usable as a fingerprint, without the need for preliminary extraction or cleanup procedures. In detail, a REIMS source is coupled to a high-resolution tandem mass spectrometer; such coupling allows one to maximize the amount of information (discriminant features) collected for a single analysis, as well as to focus on target analytes to achieve enhanced sensitivity and selectivity. A database was created from 18 marine species typical of the Mediterranean Sea, all caught in the very small area of the Strait of Messina, and reliable identification was achieved for each species with confidence higher than 99%. One big model and three submodels were built by principal component analysis and linear discriminant analysis for unambiguous key variable identification within each class (e.g., Cephalopoda), order (e.g., Perciformes), or family (e.g., Carangidae). Graphical abstract.


Assuntos
Peixes , Espectrometria de Massas/instrumentação , Alimentos Marinhos/análise , Animais , Análise Discriminante , Desenho de Equipamento , Peixes/classificação , Análise de Alimentos/instrumentação , Mar Mediterrâneo , Análise de Componente Principal , Alimentos Marinhos/classificação
14.
Food Chem ; 295: 254-258, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174756

RESUMO

In this work, we report a simple and rapid surface-enhanced Raman scattering (SERS) method for the screening of pesticide residues on fruit peels using a portable Raman spectrometer. Adhesive tapes were used as the sampling media; the effectiveness of different tape brands was examined. Collection efficiencies were found to be 60.2 ±â€¯7.6%, 54.3 ±â€¯5.0%, and 52.3 ±â€¯9.0% on glass, aluminum foil, and fruit peels, respectively. SERS was achieved by applying silver nanoparticles (Ag NPs) to the surface of the tape after analyte collection. Preparation of the Ag NPs was optimized for pesticide detection. The limit of detection of triazophos on apple peels was 25 ng/cm2 with the portable Raman spectrometer. Considering the least favorable conditions, the calculated detection limit was 0.0225 mg/kg, which is an order of magnitude less than the maximum residue limit (MRL, 0.2 mg/kg) in China. The method is sufficiently sensitive for use in field analysis.


Assuntos
Contaminação de Alimentos/análise , Frutas/química , Resíduos de Praguicidas/análise , Análise Espectral Raman/métodos , Adesivos/química , China , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Limite de Detecção , Malus/química , Nanopartículas Metálicas/química , Organotiofosfatos/análise , Prata/química , Análise Espectral Raman/instrumentação , Triazóis/análise
15.
Food Chem ; 297: 124969, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253282

RESUMO

The wide use of tetracyclines (TCs) for prevention and therapy of animal diseases may result in excessive residues in animal products, which could pose serious risks to human health. A novel molybdenum disulfide nanoplates (MoS2 NPs)-based fluorescent sensor for tetracycline (TET) is reported. The MoS2 NPs, synthesized via a facile bottom-up hydrothermal route, showed blue fluorescence at 430 nm in aqueous solution. Interestingly, its fluorescence was quenched significantly upon addition of TET, which is mainly due to a combination of the inner filter effect and electron transfer. Thus, the MoS2 NPs based fluorescence sensor was delineated for the detection of TET. The methodology here presented showed a low detection limit of 0.032 µM and satisfied recoveries from 88.46% to 108.62% in spiked milk, milk powder and bovine muscle samples.


Assuntos
Dissulfetos/química , Contaminação de Alimentos/análise , Leite/química , Molibdênio/química , Nanoestruturas/química , Tetraciclinas/análise , Animais , Antibacterianos/análise , Bovinos , Fluorescência , Análise de Alimentos/instrumentação , Análise de Alimentos/métodos , Limite de Detecção , Músculo Esquelético/química , Carne Vermelha/análise , Sensibilidade e Especificidade , Espectrometria de Fluorescência/métodos
16.
Food Chem ; 297: 124962, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253288

RESUMO

Ferrocene-based nanoporous organic polymer (Fc-NOP) was used as solid-phase extraction (SPE) adsorbent and showed excellent adsorption capacity for chlorophenols (CPs) compared with commercial C18 and multi-walled carbon nanotubes. Then, a SPE method with Fc-NOP packed cartridge combined with HPLC-UV detection was developed to determine CPs in tap water, black tea drinks and peach juice samples. Under optimal conditions, the detection limits of the method measured at the signal to noise ratio of 3 (S/N = 3) were 0.04-0.06 ng mL-1 for tap water and 0.10-0.20 ng mL-1 for black tea drinks and peach juice samples. Satisfactory method recoveries were achieved in the range of 87.6-119% with relative standard deviations of 3.11-7.83%. Result proved that this method was a sensitive and efficient method for determination of trace CPs in foods. The extraction result for more other compounds confirmed that the developed method had a great application potential for analysis of other trace pollutants in food samples.


Assuntos
Clorofenóis/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Polímeros/química , Extração em Fase Sólida/métodos , Adsorção , Clorofenóis/isolamento & purificação , Cromatografia Líquida de Alta Pressão/métodos , Compostos Ferrosos/química , Análise de Alimentos/instrumentação , Água Doce/análise , Sucos de Frutas e Vegetais/análise , Limite de Detecção , Metalocenos/química , Nanoporos , Nanotubos de Carbono/química , Prunus persica/química , Extração em Fase Sólida/instrumentação , Chá/química , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
17.
Food Chem ; 297: 124968, 2019 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-31253322

RESUMO

A novel electrochemical sensor was developed combination molecularly imprinted polymers (MIPs) with nanowell technology, and which was utilized for sensitive and selective 17ß-estradiol (17ß-E2) detection. A nanowell gold film with a thickness of 120 nm and a pore size of ∼20 nm was immobilized onto gold electrode surface to form a nanowell-based electrode. MIPs was then synthesized onto the nanowell-based electrode using electro-polymerization method, and then the nanowell-based MIP electrochemical sensor was formed. This sensor surface exhibited 3D-nanowell structure with higher surface area and enhanced electron-transport ability, while MIPs afford stronger recognition capability with higher selectivity and specificity. Most importantly, the developed sensor was validated for 17ß-E2 detection in food samples with larger detection range from 1 × 10-12 to 1 × 10-5 and lower detection limit of 1 × 10-13. Therefore, such nanowell-based MIP electrochemical sensor may be a promising candidate electrochemical sensor for trace pollution detection in food samples.


Assuntos
Técnicas Eletroquímicas/instrumentação , Estradiol/análise , Análise de Alimentos/métodos , Impressão Molecular/métodos , Nanoestruturas/química , Técnicas Eletroquímicas/métodos , Eletrodos , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Ouro/química , Limite de Detecção , Polimerização , Polímeros/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade
18.
Food Chem ; 295: 36-41, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174769

RESUMO

TOB aptamer can be adsorbed on the AuNPs surface to form AuNPs-aptamer complexation to prevent AuNPs aggregation in high salt solution. When TOB was added to the AuNPs solution, the aptamer would bind with TOB and depart from the AuNPs surface. The amount of the AuNPs-aptamer complexation depends on the TOB concentration. Different concentration of AuNPs-aptamer can catalyze the reduction reaction of CuSO4 to produce different size Cu2O particle. The resonance scattering peak intensities are correlated with the Cu2O size. Large size Cu2O particle as a resonance scattering spectroscopy probe can remarkable improve the TOB detection sensitivity. We have succeeded to detect the trace TOB in aqueous solutions. The linear range and limit of detection were 0.50-17 nM and 0.19 nM, respectively. This simple and inexpensive method exhibited high sensitivity and selectivity, which was successfully used to detect TOB in milk. The results indicated the accuracy and precision were satisfied.


Assuntos
Aptâmeros de Nucleotídeos/química , Análise de Alimentos/métodos , Leite/química , Análise Espectral/métodos , Tobramicina/análise , Adsorção , Animais , Técnicas Biossensoriais/métodos , Catálise , Sulfato de Cobre/química , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Ouro/química , Limite de Detecção , Nanopartículas Metálicas/química , Pasteurização , Sensibilidade e Especificidade , Análise Espectral/instrumentação
19.
Food Chem ; 295: 395-402, 2019 Oct 15.
Artigo em Inglês | MEDLINE | ID: mdl-31174774

RESUMO

A simple and rapid method for animal species identification to prevent food adulteration based on mitochondrial DNA using two independent multiplex polymerase chain reactions (PCRs) and microchip electrophoresis was developed. This method was designed to identify fourteen domestic animals (Group I: cattle, donkey, dog, fox, raccoon-dog, deer and horse; Group II: pig, sheep, goat, chicken, duck, cat and mouse) simultaneously using ten pairs of primers and three of which were degenerate primers. Sequences for species-specific primers were generated based on mitochondrial genes, including 12S rRNA, 16S rRNA, ND2 and CO I. This method was validated in terms of the specificity, sensitivity and practicability, and the developed multiplex PCR method was able to correctly identify animal species of raw meats and processed meat products. The detection limits of two multiplex PCRs were 0.02 ng DNA for animal species in Group I and 0.2 ng DNA for Group II, respectively.


Assuntos
Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Carne/análise , Reação em Cadeia da Polimerase Multiplex/métodos , Animais , Bovinos/genética , Galinhas/genética , Primers do DNA , DNA Mitocondrial/genética , Cervos/genética , Patos/genética , Equidae/genética , Análise de Alimentos/instrumentação , Genes Mitocondriais , Cabras/genética , Cavalos/genética , Camundongos/genética , Reação em Cadeia da Polimerase Multiplex/instrumentação , RNA Ribossômico , RNA Ribossômico 16S , Ovinos/genética , Especificidade da Espécie , Suínos/genética
20.
Food Chem ; 293: 378-386, 2019 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-31151625

RESUMO

Considering the negative impacts on human health and the environment, determinations of arsenic (As) and antimony (Sb), is of unquestionable importance. The present study describes the development of innovative and practical deep eutectic solvent (DES) based vortex assisted microextraction (DES-VAME) method for preconcentration of As and Sb from environmental waters, honey and rice prior to analysis by hydride generation-atomic absorption spectrometry (HG-AAS). The use of As(III) and Sb(III) in presence of dithizone at pH 10.5 by means of donor-acceptor mechanism were decided as analytes. Total As and Sb were determined after reduction process. The analytical properties obtained following optimization were as follows. Limit of detection (LOD), precision (as RSD%), recoveries and enhancement factor for As and Sb were calculated as 7.5 ng L-1/15.6 ng L-1, 2.1% /2.7%, 93.5%/96.2% and 104/85, respectively. Following validation with certified reference material, the method was successfully applied to the analysis of real samples.


Assuntos
Antimônio/isolamento & purificação , Arsênico/isolamento & purificação , Análise de Alimentos/métodos , Microextração em Fase Líquida/métodos , Antimônio/análise , Arsênico/análise , Análise de Alimentos/instrumentação , Contaminação de Alimentos/análise , Mel/análise , Concentração de Íons de Hidrogênio , Limite de Detecção , Microextração em Fase Líquida/instrumentação , Oryza/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Solventes/química , Espectrofotometria Atômica/métodos , Poluentes Químicos da Água/análise , Poluentes Químicos da Água/isolamento & purificação
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