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1.
Spectrochim Acta A Mol Biomol Spectrosc ; 173: 849-853, 2017 Feb 15.
Artigo em Inglês | MEDLINE | ID: mdl-27816884

RESUMO

Headspace mass-spectrometry (HS-MS), mid infrared (MIR) and UV-vis spectroscopy were used to authenticate whisky samples from different origins and ways of production ((Irish, Spanish, Bourbon, Tennessee Whisky and Scotch). The collected spectra were processed with partial least-squares discriminant analysis (PLS-DA) to build the classification models. In all cases the five groups of whiskies were distinguished, but the best results were obtained by HS-MS, which indicates that the biggest differences between different types of whisky are due to their aroma. Differences were also found inside groups, showing that not only raw material is important to discriminate samples but also the way of their production. The methodology is quick, easy and does not require sample preparation.


Assuntos
Bebidas Alcoólicas/análise , Análise de Alimentos/métodos , Espectrometria de Massas/métodos , Espectrofotometria Infravermelho/métodos
2.
Food Chem ; 221: 1041-1056, 2017 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-27979057

RESUMO

Most of scientific papers concern the qualitative or semi-quantitative analysis of aroma-active terpenes in liquid food matrices. Therefore, the procedure based on solid-phase microextraction and two-dimensional gas chromatography-time-of-flight mass spectrometry for determination of monoterpenes in fresh berries was developed. The optimal extraction conditions using divinylbenzene-carboxen-polydimethylsiloxane fiber were: temperature of 50°C, extraction time of 26min, equilibrium time of 29min. The developed procedure provides a high recovery (70.8-99.2%), good repeatability (CV<10.4%), high linearity (r>0.9915) and offers practical advantages over currently used methods: reliability of compounds identification, simplicity of extraction and at least one order of magnitude lower detection limits (0.10-0.011µg/L). The method was successfully applied to determine monoterpenes in 27 berry samples of different varieties and 4 berry products. Tukey's test revealed that monoterpenes content is a reliable indicator of fruit maturity and origin. It suggests that the method may be of interest to researchers and food industry.


Assuntos
Frutas/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Monoterpenos/análise , Microextração em Fase Sólida/métodos , Dimetilpolisiloxanos/análise , Cromatografia Gasosa-Espectrometria de Massas/normas , Polivinil/análise , Reprodutibilidade dos Testes , Microextração em Fase Sólida/normas , Temperatura , Terpenos/análise
3.
J Sci Food Agric ; 97(4): 1316-1325, 2017 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-27342385

RESUMO

BACKGROUND: Vodka is a spirit-based beverage made from ethyl alcohol of agricultural origin. At present, increasingly more vodka brands have labels that specify the botanical origin of the product. Until now, the techniques for distinguishing between vodkas of different botanical origin have been costly, time-consuming and insufficient for making a distinction between vodka produced from similar raw materials. Therefore, it is of utmost importance to find a fast and relatively inexpensive technique for conducting such tests. RESULTS: In the present study, we employed comprehensive two-dimensional gas chromatography (GC×GC) and an electronic nose based on the technology of ultra-fast GC with chemometric methods such as partial least square discriminant analysis, discriminant function analysis and soft independent modeling of class analogy. CONCLUSION: Both techniques allow a distinction between the vodkas produced from different raw materials. In the case of GC×GC, the differences between vodkas were more noticeable than in the analysis by electronic nose; however, the electronic nose allowed the significantly faster analysis of vodkas. © 2016 Society of Chemical Industry.


Assuntos
Bebidas Alcoólicas/análise , Cromatografia Gasosa/métodos , Nariz Eletrônico , Odorantes/análise , Plantas/química , Compostos Orgânicos Voláteis/análise , Análise Discriminante , Grão Comestível/química , Rotulagem de Alimentos , Humanos , Análise dos Mínimos Quadrados , Modelos Biológicos , Modelos Estatísticos , Tubérculos/química , Poaceae/química , Análise de Componente Principal , Solanum tuberosum/química , Especificidade da Espécie
4.
Sensors (Basel) ; 16(10)2016 Oct 09.
Artigo em Inglês | MEDLINE | ID: mdl-27735832

RESUMO

The capability of a phthalocyanine-based voltammetric electronic tongue to analyze strong alcoholic beverages has been evaluated and compared with the performance of spectroscopic techniques coupled to chemometrics. Nalewka Polish liqueurs prepared from five apple varieties have been used as a model of strong liqueurs. Principal Component Analysis has demonstrated that the best discrimination between liqueurs prepared from different apple varieties is achieved using the e-tongue and UV-Vis spectroscopy. Raman spectra coupled to chemometrics have not been efficient in discriminating liqueurs. The calculated Euclidean distances and the k-Nearest Neighbors algorithm (kNN) confirmed these results. The main advantage of the e-tongue is that, using PLS-1, good correlations have been found simultaneously with the phenolic content measured by the Folin-Ciocalteu method (R² of 0.97 in calibration and R² of 0.93 in validation) and also with the density, a marker of the alcoholic content method (R² of 0.93 in calibration and R² of 0.88 in validation). UV-Vis coupled with chemometrics has shown good correlations only with the phenolic content (R² of 0.99 in calibration and R² of 0.99 in validation) but correlations with the alcoholic content were low. Raman coupled with chemometrics has shown good correlations only with density (R² of 0.96 in calibration and R² of 0.85 in validation). In summary, from the three holistic methods evaluated to analyze strong alcoholic liqueurs, the voltammetric electronic tongue using phthalocyanines as sensing elements is superior to Raman or UV-Vis techniques because it shows an excellent discrimination capability and remarkable correlations with both antioxidant capacity and alcoholic content-the most important parameters to be measured in this type of liqueurs.

5.
J Anal Methods Chem ; 2016: 8763436, 2016.
Artigo em Inglês | MEDLINE | ID: mdl-27446633

RESUMO

Spirit beverages are a diverse group of foodstuffs. They are very often counterfeited which cause the appearance of low quality products or wrongly labelled products on the market. It is important to find a proper quality control and botanical origin method enabling the same time preliminary check of the composition of investigated samples, which was the main goal of this work. For this purpose, the usefulness of electronic nose based on ultra-fast gas chromatography (fast GC e-nose) was verified. A set of 24 samples of raw spirits, 33 samples of vodkas, and 8 samples of whisky were analysed by fast GC e-nose. Four data analysis methods were used. The PCA was applied for the visualization of dataset, observation of the variation inside groups of samples, and selection of variables for the other three statistical methods. The SQC method was utilized to compare the quality of the samples. Both the DFA and SIMCA data analysis methods were used for discrimination of vodka, whisky, and spirits samples. The fast GC e-nose combined with four statistical methods can be used for rapid discrimination of raw spirits, vodkas, and whisky and in the same for preliminary determination of the composition of investigated samples.

6.
Crit Rev Anal Chem ; 45(3): 201-25, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-25849822

RESUMO

Spirit-based beverages are alcoholic drinks; their production processes are dependent on the type and origin of raw materials. The composition of this complex matrix is difficult to analyze, and scientists commonly choose gas chromatography techniques for this reason. With a wide selection of extraction methods and detectors it is possible to provide qualitative and quantitative analysis for many chemical compounds with various functional groups. This article describes different types of gas chromatography techniques and their most commonly used associated extraction techniques (e.g., LLE, SPME, SPE, SFE, and SBME) and detectors (MS, TOFMS, FID, ECD, NPD, AED, O or EPD). Additionally, brief characteristics of internationally popular spirit-based beverages and application of gas chromatography to the analysis of selected alcoholic drinks are presented.


Assuntos
Bebidas Alcoólicas/análise , Cromatografia Gasosa/métodos , Microextração em Fase Sólida/métodos , Compostos Orgânicos Voláteis/análise
7.
Environ Sci Pollut Res Int ; 22(15): 11940-54, 2015 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-25869437

RESUMO

The results of studies conducted in Gdansk in the period from January to December 2013 and focused on the determination of BTEX in the atmospheric air are presented. At the stage of the isolation and/or enrichment of analytes from the gaseous medium, a passive sampling technique-Radiello® diffusive passive samplers, was applied. The time-weighted average annual concentration of benzene, toluene, ethylbenzene, and total xylenes determined in the monitored area was as follows: 0.66 ± 0.32, 1.63 ± 0.94, 0.67 ± 0.61, and 2.9 ± 2.7 µg/m(3). As a result of the research, the potential emission sources of BTEX, which activity has a significant impact on the concentration of these compounds in the atmosphere in the Gdansk area, were identified. A comparison of the accuracy and precision of the results of benzene concentrations in the atmosphere obtained by the BTEX automatic analyzer and passive techniques was performed. Moreover, a significant influence of meteorological conditions, such as air temperature, intensity of solar radiation, velocity and direction of wind, humidity, and rainfall on the benzene content in ambient air was shown. Additionally, in order to determine the conditions in the area covered by the monitoring, information about atmospheric stability and the height of the mixing layer was presented.


Assuntos
Poluentes Atmosféricos/análise , Poluição do Ar/análise , Compostos Orgânicos Voláteis/análise , Atmosfera , Cidades , Atividades Humanas , Humanos , Polônia , Estações do Ano
8.
J Sci Food Agric ; 95(11): 2159-66, 2015 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-25315338

RESUMO

Whisky (whiskey) is one of the most popular spirit-based drinks made from malted or saccharified grains, which should mature for at least 3 years in wooden barrels. High popularity of products usually causes a potential risk of adulteration. Thus authenticity assessment is one of the key elements of food product marketing. Authentication of whisky is based on comparing the composition of this alcohol with other spirit drinks. The present review summarizes all information about the comparison of whisky and other alcoholic beverages, the identification of type of whisky or the assessment of its quality and finally the authentication of whisky. The article also presents the various techniques used for analyzing whisky, such as gas and liquid chromatography with different types of detectors (FID, AED, UV-Vis), electronic nose, atomic absorption spectroscopy and mass spectrometry. In some cases the application of chemometric methods is also described, namely PCA, DFA, LDA, ANOVA, SIMCA, PNN, k-NN and CA, as well as preparation techniques such SPME or SPE.


Assuntos
Bebidas Alcoólicas/análise , Análise de Alimentos/métodos , Contaminação de Alimentos/análise , Rotulagem de Alimentos , Nariz Eletrônico , Etanol/análise , Humanos
9.
Sensors (Basel) ; 14(6): 10709-24, 2014 Jun 18.
Artigo em Inglês | MEDLINE | ID: mdl-24945677

RESUMO

The paper presents practical utilization of an electronic nose prototype, based on the FIGARO semiconductor sensors, in fast classification of Polish honey types-acacia flower, linden flower, rape, buckwheat and honeydew ones. A set of thermostating modules of the prototype provided gradient temperature characteristics of barbotage-prepared gas mixtures and stable measurement conditions. Three chemometric data analysis methods were employed for the honey samples classification: principal component analysis (PCA), linear discriminant analysis (LDA) and cluster analysis (CA) with the furthest neighbour method. The investigation confirmed usefulness of this type of instrument in correct classification of all aforementioned honey types. In order to provide optimum measurement conditions during honey samples classification the following parameters were selected: volumetric flow rate of carrier gas-15 L/h, barbotage temperature-35 °C, time of sensor signal acquisition since barbotage process onset-60 s. Chemometric analysis allowed discrimination of three honey types using PCA and CA and all five honey types with LDA. The reproducibility of 96% of the results was within the range 4.9%-8.6% CV.


Assuntos
Biomimética/instrumentação , Condutometria/instrumentação , Análise de Alimentos/instrumentação , Calefação/instrumentação , Mel/análise , Nariz/fisiologia , Olfato/fisiologia , Desenho de Equipamento , Análise de Falha de Equipamento , Mel/classificação , Humanos , Transdutores
10.
Anal Bioanal Chem ; 406(20): 4965-86, 2014 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-24908404

RESUMO

A reliable and repeatable isotachophoretic method for the simultaneous determination of K(+), Na(+), Ca(2+), Mg(2+), and ammonium in berries of different blue honeysuckle cultivars was developed. The usefulness of the complex-forming equilibria in determining the cations mentioned above was studied. The addition of 7.5 mM 18-crown-6 and 2 mM α-hydroxyisobutyric acid to sulfuric acid enhanced the separation capacity of the leading electrolyte. The terminating electrolyte of 10 mM TRIS buffered to pH 4.30 was chosen as most appropriate for these studies. An ultrasound-assisted procedure for the extraction of macroelements from dried fruit of Lonicera caerulea L. was investigated using response surface methodology. The Box-Behnken experimental design showed the optimal extraction conditions as follows: temperature of 36 °C, extraction time of 42.3 min and solid-to-liquid ratio of 1:800 v/w. Detection limits for the method ranged from 0.030 to 0.097 mg/l with precision expressed by RSD ranging from 1.4 % for Mg to 4.4 % for Na. The results showed that blue honeysuckle berries are a good source of potassium, from 199 to 402 mg/100 g FW, especially 'Zielona' and 'Zojka' cultivars. The average content of other analytes in these berries was 5.2 mg Na, 24.8 mg Ca, 7.5 mg Mg and 52.0 mg ammonium per 100 g FW. The berry products contained lower amounts of minerals especially Mg and K. However, a glass of freshly squeezed juice can provide almost 20 % of the RDI of potassium. The results obtained using both the developed isotachophoretic method and ion chromatographic procedure did not differ significantly.

11.
J Agric Food Chem ; 62(7): 1423-48, 2014 Feb 19.
Artigo em Inglês | MEDLINE | ID: mdl-24506450

RESUMO

Nowadays, consumers are paying great attention to the characteristics of food such as smell, taste, and appearance. This motivates scientists to imitate human senses using devices known as electronic senses. These include electronic noses, electronic tongues, and computer vision. Thanks to the utilization of various sensors and methods of signal analysis, artificial senses are widely applied in food analysis for process monitoring and determining the quality and authenticity of foods. This paper summarizes achievements in the field of artificial senses. It includes a brief history of these systems, descriptions of most commonly used sensors (conductometric, potentiometric, amperometic/voltammetric, impedimetric, colorimetric, piezoelectric), data analysis methods (for example, artificial neural network (ANN), principal component analysis (PCA), model CIE L*a*b*), and application of artificial senses to food analysis, in particular quality control, authenticity and falsification assessment, and monitoring of production processes.


Assuntos
Técnicas Biossensoriais/métodos , Análise de Alimentos/métodos , Técnicas Biossensoriais/instrumentação , Nariz Eletrônico , Análise de Alimentos/instrumentação , Humanos , Olfato , Paladar
12.
Food Chem ; 152: 88-93, 2014.
Artigo em Inglês | MEDLINE | ID: mdl-24444910

RESUMO

Terpenes are the main group of secondary metabolites, which play essential role in human. The establishment of the terpenes profile of berries of different blue honeysuckle cultivars was achieved by headspace solid-phase microextraction coupled with comprehensive two-dimensional gas chromatography with time-of-flight mass spectrometry (HS-SPME/GC×GC-TOFMS). The berries were found to contain 44 terpenes identified by GC×GC-TOFMS. From these, 10 were previously reported in blueberries. According to their chemical structure, the compounds were organised in different groups: monoterpene hydrocarbons and monoterpene oxygen-containing compounds (oxides, alcohols, aldehydes, and ketones). Positive identification of some of the compounds was performed using authentic standards, while tentative identification of the compounds was based on deconvoluted mass spectra and comparison of linear retention indices (LRI) with literature values. The major components of volatile fraction were monoterpenes, such as eucalyptol, linalool and p-cymene. Furthermore, quantitative analysis showed that eucalyptol was the most abundant bioactive terpene in analysed berries (12.4-418.2 µg/L).


Assuntos
Frutas/química , Cromatografia Gasosa-Espectrometria de Massas/métodos , Lonicera/química , Extratos Vegetais/química , Terpenos/química , Estrutura Molecular , Extratos Vegetais/isolamento & purificação , Microextração em Fase Sólida , Terpenos/isolamento & purificação
13.
Sensors (Basel) ; 13(12): 15954-67, 2013 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-24287525

RESUMO

The paper presents the application of an electronic nose instrument to fast evaluation of agricultural distillates differing in quality. The investigations were carried out using a prototype of electronic nose equipped with a set of six semiconductor sensors by FIGARO Co., an electronic circuit converting signal into digital form and a set of thermostats able to provide gradient temperature characteristics to a gas mixture. A volatile fraction of the agricultural distillate samples differing in quality was obtained by barbotage. Interpretation of the results involved three data analysis techniques: principal component analysis, single-linkage cluster analysis and cluster analysis with spheres method. The investigations prove the usefulness of the presented technique in the quality control of agricultural distillates. Optimum measurements conditions were also defined, including volumetric flow rate of carrier gas (15 L/h), thermostat temperature during the barbotage process (15 °C) and time of sensor signal acquisition from the onset of the barbotage process (60 s).


Assuntos
Agricultura/instrumentação , Agricultura/métodos , Nariz Eletrônico , Gases/análise , Odorantes/análise , Controle de Qualidade , Análise de Componente Principal/métodos , Semicondutores , Temperatura
14.
Sensors (Basel) ; 13(4): 5008-27, 2013 Apr 15.
Artigo em Inglês | MEDLINE | ID: mdl-23591962

RESUMO

The paper presents the potential of an electronic nose technique in the field of fast diagnostics of patients suspected of Chronic Obstructive Pulmonary Disease (COPD). The investigations were performed using a simple electronic nose prototype equipped with a set of six semiconductor sensors manufactured by FIGARO Co. They were aimed at verification of a possibility of differentiation between model reference mixtures with potential COPD markers (N,N-dimethylformamide and N,N-dimethylacetamide). These mixtures contained volatile organic compounds (VOCs) such as acetone, isoprene, carbon disulphide, propan-2-ol, formamide, benzene, toluene, acetonitrile, acetic acid, dimethyl ether, dimethyl sulphide, acrolein, furan, propanol and pyridine, recognized as the components of exhaled air. The model reference mixtures were prepared at three concentration levels-10 ppb, 25 ppb, 50 ppb v/v-of each component, except for the COPD markers. Concentration of the COPD markers in the mixtures was from 0 ppb to 100 ppb v/v. Interpretation of the obtained data employed principal component analysis (PCA). The investigations revealed the usefulness of the electronic device only in the case when the concentration of the COPD markers was twice as high as the concentration of the remaining components of the mixture and for a limited number of basic mixture components.


Assuntos
Biomarcadores/análise , Nariz Eletrônico , Doença Pulmonar Obstrutiva Crônica/diagnóstico , Gases/análise , Humanos , Análise de Componente Principal , Padrões de Referência , Processamento de Sinais Assistido por Computador , Volatilização
15.
Rev Sci Instrum ; 81(4): 045104, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20441365

RESUMO

The paper presents a prototype of a mobile monitoring system for measuring the levels of the main traffic air pollutants (C(6)H(6), NO(2), NO(x), CO, and CO(2),) in cities. The novelty of the proposed system lies in the fact that it can be utilized to monitor emissions from urban traffic along roads and areas where traditional monitoring stations cannot be placed. In the proposed system, the monitoring device can be mounted on any moving vehicle (such as a car, bus, or truck) rather than be attached to a dedicated van, as most systems of this kind found in literature are. Analyzers used in this system are small portable structures that contain an electronic instrument to measure, record, and transmit relevant data on concentrations of the pollutants to a website. The model outcome for carbon monoxide obtained in functional tests in real conditions is also presented here. Data on temporal changes of carbon monoxide concentration are compared against meteorological parameters and speed of the vehicle. Spatial interpolation techniques are applied to obtain a nonplanar visualization of carbon monoxide and benzene concentrations in the main arteries of a city.

16.
Anal Chim Acta ; 613(1): 64-73, 2008 Apr 14.
Artigo em Inglês | MEDLINE | ID: mdl-18374703

RESUMO

An analytical method for the determination of fatty acid ethyl esters in raw spirits of different quality or produced from various raw materials has been developed and optimized. A combination of headspace solid phase microextraction (HS-SPME) as the extraction technique and gas chromatography with flame ionization detection (GC-FID) as the determination technique was utilized. HS-SPME conditions such as: type of the stationary phase of the fiber, ethanol content, sample volume, extraction temperature and time, salt addition and sample agitation were investigated to determine the most suitable conditions for the analysis of volatile fatty acid ethyl esters in raw spirits. The quantification method was an internal standardization using methyl octanoate as the internal standard. The method's detection limits (MDLs) for the individual ethyl esters ranged from 26.8 to 0.0470 microg L(-1) 20% EtOH. The feasibility of SPME for the quantitative analysis of fatty acid ethyl esters in raw spirits of different organoleptic quality was demonstrated. High precision and simple sample preparation enable the use of this method for routine investigations in both industrial and research laboratories.

17.
J Biochem Biophys Methods ; 70(2): 275-88, 2007 Mar 10.
Artigo em Inglês | MEDLINE | ID: mdl-17107713

RESUMO

The paper presents recent trends in solventless sample preparation techniques for environmental analysis. First, a general classification of solventless methods is given. Next, three of them, treated as preferable techniques, i.e. SPME, SDME and HS, are presented in detail, with respect to their usability and effectiveness for environmental samples. Examples of all discussed techniques are given in the tables.


Assuntos
Cromatografia/tendências , Monitoramento Ambiental/métodos , Poluentes Ambientais/análise , Microextração em Fase Sólida/tendências , Manejo de Espécimes/tendências , Solventes/química
18.
J Chromatogr A ; 984(1): 89-96, 2003 Jan 10.
Artigo em Inglês | MEDLINE | ID: mdl-12564679

RESUMO

A method was developed for the determination of C1-C6 carbonyl compounds in alcoholic solutions using pentafluorobenzoxymation followed by headspace sampling solid-phase microextraction and subsequent analysis by GC with electron-capture detection. Experimental conditions-alcohol content, exposure time, temperature and sample agitation were optimised. In this method, a spirit or distilled alcoholic beverage is first adjusted to 20% (v/v) alcohol. Detection limits for particular aldehydes and ketone varied from 0.05 to 0.5 microg/l and relative standard deviation was between 2.3 and 20%. Generally, the method showed good linearity for the tested concentration range 8 microg/l-0.32 mg/l with regression coefficients ranging between 0.9434 and 0.9983. The method was applied to the analysis of real alcoholic beverages (vodkas).


Assuntos
Bebidas/análise , Cromatografia Gasosa/métodos , Etanol , Calibragem , Volatilização
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