Literatura científica selecionada sobre o tema "HPLC UV-VIS/DAD"
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Artigos de revistas sobre o assunto "HPLC UV-VIS/DAD"
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Jančářová, I., A. Vondráčková, A. Šlampová e V. Kubáň. "Capillary electrophoretic and liquid chromatographic determination of synthetic dyes in non-alcoholic drinks and wine samples". Czech Journal of Food Sciences 18, No. 2 (1 de janeiro de 2000): 41–48. http://dx.doi.org/10.17221/8307-cjfs.
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Synthetic dyes in wine, juices, lemonades, instant and non-alcoholic drinks were determined by capillary electrophoresis (CE) and liquid chromatography (HPLC) with UV-VIS diode-array detection (DAD). The results were in the very good agreement (the relative deviations D < 16%, D < 14% and D < 15% between CE/UV-VIS, CE/HPLC and HPLC/UV-VIS, respectively, D < 6% in majority of samples) with those obtained by UV-VIS spectrophotometry. A borate/phosphate buffer of pH 9.0 (12.5mM borate and 12.5mM phosphate) containing 40mM sodium dodecylsulfate (SDS) was selected as an electrolyte for CE. A 50mM phosphate buffer and 5mM tetrabutylammonium hydroxide (TBAOH) water solution of pH 4.2 in 38% (v/v) acetonitrile were used as a mobile phase for isocratic HPLC separation on Sepharon SGX C18 (3 × 150 mm, 5 µm) column. RSDs for individual colorants were < 0.5% for migration times, < 3% for electrophoretic peak areas, < 0.9% for retention times and < 2.4% for HPLC peak areas. Limits of quantitations (LOQs for 10 S/N) were 1.5–3.3 mg/l for CE when using 50 µm I.D. separation capillary or 0.2 to 0.4 mg/l for HPLC.
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Pereira, Ana C., Marco S. Reis, Pedro M. Saraiva e José C. Marques. "Madeira wine ageing prediction based on different analytical techniques: UV–vis, GC-MS, HPLC-DAD". Chemometrics and Intelligent Laboratory Systems 105, n.º 1 (janeiro de 2011): 43–55. http://dx.doi.org/10.1016/j.chemolab.2010.10.009.
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Jerković, Igor, Marina Kranjac, Zvonimir Marijanović, Marina Zekić, Ani Radonić e Carlo Tuberoso. "Screening of Satureja subspicata Vis. Honey by HPLC-DAD, GC-FID/MS and UV/VIS: Prephenate Derivatives as Biomarkers". Molecules 21, n.º 3 (21 de março de 2016): 377. http://dx.doi.org/10.3390/molecules21030377.
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Pinto, Catarina, e J. Sérgio Seixas de Melo. "The molecules of color in Portuguese postage stamps (1857–1909)". Pure and Applied Chemistry 90, n.º 3 (23 de fevereiro de 2018): 435–45. http://dx.doi.org/10.1515/pac-2017-0701.
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AbstractThe nature of the pigments or dyes used to dye the first Portuguese postage stamps has remained unknown until now. In this work, a study has been made of the inks used for red, rose, purple and orange colors in a selected number of Portuguese postage stamps from the period 1857 to 1909. This is based on analysis involving a variety of techniques (X-ray fluorescence, UV-Vis spectroscopy, HPLC-MS/HPLC-DAD, steady and time resolved fluorescence). It was found that the inks included, among others, the inorganic pigments cinnabar (HgS), lead oxide (Pb3O4) and chromate (PbCrO4), lead sulphide (PbS), and the organic compounds carminic acid and Eosin Y. The study demonstrated a non-destructive analysis method for identification of two molecules of color involving the UV-Vis (for carminic acid and Eosin Y) and fluorescence spectra, together with quantum yields and lifetimes (for Eosin Y).
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Di Ciaccio, Lucía S., Alejandra V. Catalano, Paula G. López, Dante Rojas, Diego Cristos, Renée H. Fortunato e Adriana E. Salvat. "In Vitro Antifungal Activity of Peltophorum dubium (Spreng.) Taub. extracts against Aspergillus flavus". Plants 9, n.º 4 (2 de abril de 2020): 438. http://dx.doi.org/10.3390/plants9040438.
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Aspergillus flavus is a filamentous, saprophytic fungus, whose colonization occurs mainly in cereal grains and oilseeds once harvested. Under certain conditions, it could produce mycotoxins called aflatoxins, known as powerful human liver carcinogens. The aim of the present study was to describe the antifungal activity of extracts of Peltophorum dubium, a species from northern Argentina (Oriental Chaco), against A. flavus. The antifungal activities of different collection sites are reported. The extracts exhibited a minimum inhibitory concentration of 125 µg/mL, and the differences between the treatments and the inoculum control were 11 mm of P. dubium A and 10 mm of P. dubium F in colony growth. Moreover, hyphae treated with the extracts stained blue with Evans blue showed alterations in the membrane and/or cell wall, allowing the dye income. Bio-guided fractionation, High Performance Liquid Chromatography diode array ultraviolet/visible (HPLC UV/VIS DAD), and Ultra-High Performance Liquid Chromatography Electrospray Ionization Mass Spectrometry (UPLC ESI-MS) analyses were conducted to characterize the extracts and their active fractions. The HPLC UV/VIS DAD analysis allowed the determination of the presence of flavonoids (flavonols and flavones), coumarins, terpenes, and steroids. UPLC ESI/MS analysis of active fractions revealed the presence of Kaempferol, Apigenin, Naringenin, Chrysin and Daidzein.
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Mărghitaş, Liviu Al, Daniel S. Dezmirean e Otilia Bobiş. "Important Developments in Romanian Propolis Research". Evidence-Based Complementary and Alternative Medicine 2013 (2013): 1–9. http://dx.doi.org/10.1155/2013/159392.
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The most important developments in propolis analysis and pharmacological properties are discussed. In order to help in the Romanian propolis standardization, different methodologies for chemical composition analysis (UV-VIS, HP-TLC, and HPLC-DAD) are reviewed using new approaches and software (fuzzy divisive hierarchical clustering approach and ChromQuest software) and compared with international studies made until now in propolis research. Practical applications of Romanian propolis in medicinal therapy and cosmetics are reviewed, and quality criteria for further standardization are proposed.
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Šivel, M., S. Kráčmar, B. Fišera M Klejdus e V. Kubáň. "Lutein content in marigold flower (Tagetes erecta L.) concentrates used for production of food supplements". Czech Journal of Food Sciences 32, No. 6 (27 de novembro de 2014): 521–25. http://dx.doi.org/10.17221/104/2014-cjfs.
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The RP-HPLC with UV-VIS DAD detection was employed for the separation, identification, and quantification of lutein content in Marigold flower (Tagetes erecta L.) concentrates used for the production of food supplements. The concentrates commercially available in encapsulated (“granules” – 16 samples) and powder (18 samples) forms were analysed. Only 10 samples showed lutein levels complying with lutein contents declared by the manufacturers. Marigold extract in the encapsulated form proved to be more stable against oxidation than the extract in the powder form.
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Konieczynski, Pawel. "Principal component analysis in interpretation of the results of HPLC-ELC, HPLC-DAD and essential elemental contents obtained for medicinal plant extracts". Open Chemistry 11, n.º 4 (1 de abril de 2013): 519–26. http://dx.doi.org/10.2478/s11532-012-0197-9.
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AbstractPrincipal component analysis (PCA) was applied to compare its usefulness with cluster analysis (CA), and factorial k-means analysis (fkm), for evaluating the results obtained using HPLC-DAD, HPLC-ELC and spectroscopic techniques (AAS and UV/VIS spectrometry for determining content of N, P, Fe and Cu) in aqueous extracts of seven medicinal plants. These represented the following plant species that are rich in flavonoids: Betula verrucosa Ehrh., Equisetum arvense L., Polygonum aviculare L., Viola tricolor L., Crataegus oxyacantha L., Sambucus nigra L. and Helichrysum arenarium (L.) Moench. The databases analyzed comprised four sets: 1) results obtained by the use of HPLC-DAD detection, 2) results obtained by the use of electrochemical detection (HPLC-ELC), 3) results for determining elements — total and water-extractable species, and 4) all data combined. Application of statistical methods allowed the samples to be classified into four groups: 1) Crataegus, Sambucus, 2) Equisetum, Polygonum and Viola, 3) Betula, and 4) Helichrysum, which were differentiated by characteristic patterns. PCA supported by CA, was the most suitable method, because it simultaneously allowed for reduction of multidimensionality of the databases, grouped the samples into four clusters, and made possible selection of the factors responsible for differentiation of the plant materials studied.
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Mateos-Maces, Lourdes, José Luis Chávez-Servia, Araceli Minerva Vera-Guzmán, Elia Nora Aquino-Bolaños, Jimena E. Alba-Jiménez e Bethsabe Belem Villagómez-González. "Edible Leafy Plants from Mexico as Sources of Antioxidant Compounds, and Their Nutritional, Nutraceutical and Antimicrobial Potential: A Review". Antioxidants 9, n.º 6 (20 de junho de 2020): 541. http://dx.doi.org/10.3390/antiox9060541.
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A review of indigenous Mexican plants with edible stems and leaves and their nutritional and nutraceutical potential was conducted, complemented by the authors’ experiences. In Mexico, more than 250 species with edible stems, leaves, vines and flowers, known as “quelites,” are collected or are cultivated and consumed. The assessment of the quelite composition depends on the chemical characteristics of the compounds being evaluated; the protein quality is a direct function of the amino acid content, which is evaluated by high-performance liquid chromatography (HPLC), and the contribution of minerals is evaluated by atomic absorption spectrometry, inductively coupled plasma-optical emission spectrometry (ICP-OES) or ICP mass spectrometry. The total contents of phenols, flavonoids, carotenoids, saponins and other general compounds have been analyzed using UV-vis spectrophotometry and by HPLC. For the determination of specific compounds such as phenolic compounds, flavonoids, organic acids and other profiles, it is recommended to use HPLC-DAD, UHPLC-DAD, UFLC-PDA or gas chromatography-mass spectrometry. The current biochemical analysis and biological evaluations were performed to understand the mechanisms of action that lead to decreased glucose levels and lipid peroxidation, increased hypoglycemic and antitumor activity, immune system improvement, increased antibacterial and antifungal activity and, in some cases, anti-Helicobacter pylori activity.
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Sholihah, Shofuro, Norisca Aliza Putriana e Rimadani Pratiwi. "Review Metode Analisis Warfarin dalam Plasma dengan Berbagai Instrumen". Jurnal Sains Farmasi & Klinis 8, n.º 2 (6 de agosto de 2021): 128. http://dx.doi.org/10.25077/jsfk.8.2.128-144.2021.
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Warfarin merupakan obat antikoagulan oral yang digunakan untuk menangani penyakit terkait dengan tromboembolisme. Warfarin memiliki indeks terapi yang sempit serta memiliki kecenderungan berinteraksi dengan obat maupun herba sehingga membutuhkan pemantauan yang cermat pada efek farmakologi yang ditimbulkan. Penentuan pemberian dosis serta pengamatan efek dari interaksi warfarin dengan obat atau herba salah satunya dapat diketahui dengan menganalisis konsentrasi warfarin dalam plasma darah. Artikel ini merupakan kajian pustaka yang bertujuan untuk memberikan tinjauan mengenai metode yang digunakan untuk menganalisis konsentrasi warfarin dalam plasma darah serta teknik preparasi sampelnya. Metode yang digunakan dalam review artikel ini menggunakan penelusuran melalui basis data PubMed®. Hasil yang didapatkan bahwa metode yang umum digunakan untuk determinasi warfarin dalam plasma darah yakni high-performance liquid chromatography (HPLC) serta ultra-HPLC dengan detektor ultraviolet (UV), fluoresensi (FLD), diode array (DAD), maupun spektroskopi massa (MS). Metode lainnya yaitu spektrofotometri UV/Vis dan spektrofotometri fluoresensi serta elektroforesis. Dari metode tersebut, metode HPLC dengan detektor spektroskopi massa paling banyak digunakan untuk menganalisis warfarin serta teknik preparasi sampel yang umum digunakan yakni preparasi sampel yang umum digunakan yakni presipitasi protein menggunakan asetonitril sebagai protein presipitan serta penambahan asam untuk meningkatkan nilai recovery warfarin dari plasma darah
Teses / dissertações sobre o assunto "HPLC UV-VIS/DAD"
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Rouxinol, Maria Inês Silva Caçador Pereira. "Determinação das principais antocianinas em castas tintas no Alentejo". Master's thesis, Universidade de Évora, 2016. http://hdl.handle.net/10174/20869.
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Os compostos fenólicos (incluindo as antocianinas) estão presentes no vinho e possuem
atividade antioxidante relevante, protegendo as células contra processos oxidativos, podendo
ser importantes na prevenção de doenças cardiovasculares, neurodegenerativas e
cancerígenas, entre outras.
O objetivo deste trabalho é a avaliação da composição em antocianinas em castas de uvas
tintas desde ao pintor até ao final da maturação. As antocianinas foram quantificadas por
HPLC. Adicionalmente o conteúdo total em compostos fenólicos foi determinado por
espectrometria UV-Vis. Observou-se nos resultados de todas as análises efetuadas um
padrão repetido e consistente de evolução dos compostos em estudo.
Foi ainda testado neste trabalho a quantificação das antocianinas totais, de malvidina-3-
glucósido e dos compostos fenólicos totais através de um método espectroscópico baseado
no espectro de absorção da zona UV. Embora a calibração deste método não tenha
apresentado valores muito robustos, poderá no futuro ser utilizada como método alternativo
rápido para a quantificação de antocianinas e compostos fenólicos; Abstract:
«Quantification of Anthocyanins in Red Wine Grapes in Alentejo»
Phenolic Compounds (including anthocyanins) are present in wine and possess significant
antioxidant activity, protecting cells against oxidative processes, and preventing prevent
cardiovascular, neurodegenerative and cancer diseases, among others.
The aim of this study is the evaluation of the anthocyanins composition in red wine grapes
from the verásion until the end of ripening. Anthocyanins were quantified by HPLC.
Additionally the total content of phenolic compounds was determined by UV-Vis
spectrometry. It was possible to verify in all tests that the results have a consistent evolution
pattern considering different tested compounds.
Anthocyanins, malvidin-3-glucoside and phenolic compounds were also quantified by a
spectroscopic method based on the UV absorption spectrum. Although the calibration of this
method has not presented very sturdy values, it should be improved in the future and used as
an alternative method for rapid quantification of anthocyanins and phenolic content.
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Fróes, Márcia Beatriz Reis. "Desenvolvimento de método para determinação de resíduos de pesticidas em frutas exóticas por dispersão da matriz em fase sólida e cromatografia líquida de alta eficiência com detector espectrofotométrico de absorção no UV-VIS com arranjo de diodos". Universidade Federal de Sergipe, 2010. https://ri.ufs.br/handle/riufs/6057.
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The fruits are an excellent source of nutrition, providing significant health benefits. The consumption of fruits with new flavors and high nutritional characteristics, called superfruits has been a worldwide trend, among them are
assai and cupuassu. The presence of pesticide residues in food is a risk to the population's health. For this reagor, it is important to develop analytical methods for pesticide residues determination. The literature does not describe method for
determination of pesticides in assai and cupuassu. In this context, this work aims to develop a new method based on MSPD and HPLC-UV/DAD determination of bromuconazole, fenbuconazole, parathion methyl, kresoxm-methyl and
teflubenzuron in exotic fruits, assai and cupuassu. The extraction method based on matrix solid phase dispersion was developed and validated using different types and amounts of sorbents (neutral alumina, Florisil, silica and C18) and
organic solvents (15-30 mL) ethyl acetate, dichloromethane, cyclohexane and acetonitrile. The best results for bromuconazole, fenbuconazole, parathionmethyl and kresoxim-methyl by HPLC-UV/DAD analysis were obtained using 1:3
(w / w) sample: the solid support (neutral alumina) ratio, without clean-up, and eluted with 20 mL of ethyl acetate: cyclohexane 1:1, v / v ratio. For assai, recovery values ranged from 57 to 119% with coefficients of variation values
ranging from 1.4 to 20% for concentration levels 1, 2 and 6 μg mL-1. Detection and quantification limits ranged from 0.1 to 0.9 μg g-1 and 0.4 to 2.1 μg g-1, respectively. For cupuassu, recovery values were between 57-69%, the
concentration level of 2 μg g-1.As frutas constituem uma excelente fonte de alimentação, proporcionando importantes benefícios à saúde. O consumo de frutas com novos sabores e características nutricionais elevadas, chamadas de superfrutas, tem sido uma tendência mundial, entre elas se encontram o açaí e o cupuaçu. A presença de resíduos de pesticidas em alimentos constitui um risco a saúde da população, sendo importante o estudo de métodos analíticos para a determinação de seus resíduos. A literatura não registra método para a determinação de pesticidas em açaí e cupuaçu. Neste contexto, este trabalho tem como objetivo o desenvolvimento de um método baseado na MSPD e HPLC-UV/DAD para a determinação dos pesticidas bromuconazol, fenbuconazol, parationa-metílica, cresoxim-metílico e teflubenzuron em frutas exóticas, açaí e cupuaçu. O método de extração por dispersão da matriz em fase sólida foi desenvolvido, testando-se diferentes tipos e quantidades de suporte sólido (alumina neutra, Florisil, sílica e C18) e os solventes orgânicos (15 a 30 mL) acetato de etila, diclorometano, ciclohexano e acetonitrila. Os melhores resultados para os pesticidas bromuconazol, fenbuconazol, parationa-metílica e cresoxim-metílico em análise por HPLC-UV/DAD foram obtidas na utilização da proporção 1:3 (m/m) amostra:suporte sólido do solvente alumina neutra, sem etapa de limpeza (clean-up), e eluição com 20 mL de acetato de etila:ciclohexano na proporção 1:1, v/v. Para a matriz açaí, valores de recuperação entre 57-119 % e valores de coeficientes de variação na faixa de 1,4-20 % para os níveis de concentração 1, 2 e 6 μg mL-1, com limites de detecção e quantificação do método entre 0,1- 0,9 μg g-1 e 0,4 -2,1 μg g-1 , respectivamente. Para a matriz cupuaçu, valores de recuperação entre 57 - 69 %,ao nível de concentração de 2 μg g-1.
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Souza, Ana Jacqueline Conceição. "Desenvolvimento de método para determinação de resíduos de agrotóxicos em água de cultivo de arroz irrigado". Pós-Graduação em Química, 2017. https://ri.ufs.br/handle/riufs/6834.
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Fundação de Apoio a Pesquisa e à Inovação Tecnológica do Estado de Sergipe - FAPITEC/SERice is one of the most important crops in the world. The waters near the areas of this crop has a raised risk of contamination, once the cultivation of rice requires large quantities of pesticides. Due to their high toxicity, uncontrolled use and high solubility in water, pesticides are considered one of the main pollutants of aquatic ecosystems. This present work aims to develop an efficient method based on solid phase extraction (SPE) techniques and high performance liquid chromatography with spectrophotometric detector in the ultraviolet and visible region with diode array (HPLC UV-Vis/DAD) for determination pesticides deltamethrin, epoxiconazole, pyraclostrobin, pyriproxyfen, tebuconazole and thiamethoxan in irrigated rice water, using biochar of aguapé as an alternative adsorbent for SPE. For that, tests were carried out to optimize the chromatographic conditions and the extraction method. In the extraction stage of the pesticides, the method was optimized using the adsorbents C-18 and bio-carbon produced from aguapé. When the C-18 adsorbent was used, the best results were obtained using 10 mL of acidified acetone at pH 5,0 with formic acid solution, 69 ± 0,5 - 100 ± 5,9%. However, when the biochar was tested as an adsorbent for SPE extraction, it presented satisfactory recovery results between 70 ± 0,7% and 122 ± 10,7% for the concentration levels 0,3 to 1,0 μg mL -1. The methods developed were suitable for the determination of pesticide residues in water samples. Thus, the method of extraction using the bio-pot of water was chosen to be validated, because besides being efficient in the extraction of pesticides, it is also a sustainable option. The parameters evaluated for the validation of the method were: linearity and sensitivity, showing good linear response with determination coefficients above 0,9832 in the range of 0,025 to 10 μg mL-1; selectivity, through matrix effect studies; and limits of detection and quantification in the range of 0,01-0,08 μg mL -1, 0,04-0,3 μg mL -1, respectively.
O arroz é uma das culturas mais importantes no mundo, e as águas próximas das áreas desta cultura possuem elevado risco de contaminação, já que o cultivo de arroz requer a utilização de grandes quantidades de agrotóxicos. Devido à sua alta toxicidade, seu uso descontrolado e sua alta solubilidade em água, os agrotóxicos são considerados um dos principais poluentes dos ecossistemas aquáticos. O presente trabalho tem como objetivo desenvolver um método eficiente baseado nas técnicas de extração em fase sólida (SPE) e cromatografia líquida de alta eficiência com detector espectrofotométrico na região do ultravioleta e visível com arranjo de diodos (HPLC UV-Vis/DAD) para a determinação dos agrotóxicos deltametrina, epoxiconazol, piraclostrobina, piriproxifeno, tebuconazol e tiametoxan em água de cultivo de arroz irrigado. Para tanto, foram realizados testes para otimização das condições cromatográficas e do método de extração. Na etapa de extração dos agrotóxicos, o método foi otimizado utilizando adsorventes comerciais e alternativos. Quando se fez uso do adsorvente C-18, os melhores resultados foram obtidos utilizando 10 mL de acetona acidificado a pH 5,0 com solução de ácido fórmico, 69 ± 0,5 – 100 ± 5,9 %. Já quando o biocarvão produzido a partir de aguapé foi testado como adsorvente para a extração por SPE, apresentou resultados satisfatórios de recuperação entre 70 ± 0,7% – 122 ± 10,7% para os níveis de concentração 0,3 a 1,0 μg mL-1. Os métodos desenvolvidos se mostraram adequados para determinação de resíduos de agrotóxicos em amostras de água. Assim, o método de extração utilizando o biocarvão de aguapé foi escolhido para ser validado, pois além de ser eficiente na extração dos agrotóxicos trata-se também de uma opção sustentável. Os parâmetros avaliados para a validação do método foram: linearidade e sensibilidade, mostrando-se boa resposta linear com coeficientes de determinação superiores a 0,9832 no intervalo de 0,025 a 10 μg mL-1; seletividade, através de estudos de efeito matriz; e limites de detecção e quantificação no intervalo de 0,01 - 0,08 μg mL-1, 0,04 - 0,3 μg mL-1, respectivamente.
São Cristóvão, SE
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Komárek, Šimon. "Studium extrakce biologicky aktivních látek do tukového základu". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2020. http://www.nusl.cz/ntk/nusl-433157.
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This diploma thesis deals with macerates of comfrey (Symphytum officinale) in selected fats (food lard, cosmetic lard and almond oil). Selected fats were first characterized by dry matter content, saponification, acid, iodine number, peroxide value. At the same time, total and free fatty acids were determined using GC-FID. Macerates were prepared by extraction of comfrey roots with selected fats. In prepared macerates the change in acid and peroxide value was monitored, as well as the content of selected bioactive compounds. The content of total phytosterol and total carotenoid content was determined by UV-VIS spectrometry, phytosterols and carotenoids were also analysed using HPLC-DAD. Total phenolic content was measured using Folin-Ciocalteu reagent and antioxidant activity by ABTS assay. The measured properties were then compared with industrially produced comfrey ointment. In macerated fats the increase in acid and peroxide value was determined. Furthermore, an increase in the content of total phytosterols and total carotenoids was observed. Using HPLC-DAD the content of -sitosterol and stigmasterol was determined, but carotenoids were not detected. Of the tocopherols, only DL--tocopherol acetate was detected. During maceration, the content of total phenolic compound in fat increased, which caused a change in antioxidant activity.
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Palanová, Veronika. "Experimentální studium a teoretické modelování transdermálního transportu aktivních látek z gelových matric". Master's thesis, Vysoké učení technické v Brně. Fakulta chemická, 2016. http://www.nusl.cz/ntk/nusl-240533.
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This diploma thesis deals with design and experimental study of transdermal transport of pharmaceutically active agents from gel matrices, which contain humic substance in its structure. A model absorption membrane was represented by the skin of pig´s earlobes. The study of the release of active substances and Lignohumte was performed due to the vertical diffusion cells. The amount of released humic substance was characterized by UV-VIS method and the amount of released active agent from gel matrix was determined by HPLC-DAD. The most interesting finding of this diploma thesis was that Lignohumate enhances transdermal transport of active agents and supports their release from gel samples to the particular environment.
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Santos, Luis Fabrício Santana. "Desenvolvimento de método para determinação de resíduos de agrotóxicos na fruta exótica graviola (Anonna municata L.)". Universidade Federal de Sergipe, 2015. https://ri.ufs.br/handle/riufs/6093.
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Brazil is a great producer and consumer of fruits in the world. The soursop (Annona muricata L.) is a fruit with special flavor and aroma and with growing demand for fresh or processed consumption, such as juices, jams, fruit jellies and
ice cream. However, the culture of soursop is subjected to the action of different pests and diseases and the application of pesticides has been one of the main ways of control. The present work aims at developing a rapid and low-cost
methodology based on matrix solid phase dispersion and high-performance liquid chromatography with diode-array detection (HPLC UV-Vis/DAD) for the determination of pesticide residues of Bifenthrin, Lufenuron, Teflubenzuron,
Thiacloprid, Thiophanate-methyl and Thiamethoxam, in the exotic fruit soursop. Some tests conducted with the standards of pesticides allowed the adjustment of the chromatographic conditions for simultaneous analysis of analytes. The best
extraction conditions were obtained using 1.0 g of Florisil to 0.5 g of fresh soursop and Elution with 5 mL of Acetonitrile. The miniaturization of the extraction procedure was shown to be efficient in the extraction of pesticides. Analytical
validation was performed from the parameters: linearity and sensitivity, with coefficients of determination over 0.9995 and sensitive concentration range of 0.01 -10 g mL-1; selectivity, from the matrix effect studies; accuracy and
precision, with recovery values between -118 79% and RSD in the range of 1- 15% for concentration levels 0.1, 0.25 and 0.5 g g-1 (n = 5); and limits of detection and quantification in the intervals of 0.01-0.25 g g-1 and 0.1-0.5 g g-
1, respectively. Metal Organic Frameworks (MOF) [(Nd0,
9Eu0.1)2(DPA)3(H2O)3] was tested as sorbent for the MSPD extraction process and presented satisfactory recovery results (78-87%) compared to those achieved with Florisil.O Brasil é um importante produtor e consumidor de frutas no mundo. A graviola (Annona muricata L.) é uma fruta de sabor e aroma característicos e com crescente demanda, seja para o consumo in natura ou na forma processada, como sucos, doces, geleias e sorvetes. Todavia, a cultura da graviola está sujeita a ação de diferentes pragas e doenças e a aplicação de agrotóxicos tem sido uma das principais formas de controle. O presente trabalho tem como objetivo o desenvolvimento de uma metodologia rápida e de baixo custo baseada nas técnicas de dispersão da matriz em fase sólida (MSPD) e cromatografia líquida de alta eficiência com detector espectrofotométrico na região do ultravioleta e visível com arranjo de diodos (HPLC UV-Vis/DAD) para a determinação de resíduos dos agrotóxicos bifentrina, lufenuron, teflubenzuron, tiacloprido, tiofanato metílico e tiametoxam, na fruta exótica graviola. Testes realizados com os padrões dos agrotóxicos permitiram o ajuste das condições cromatográficas para análise simultânea dos analitos. As melhores condições de extração foram obtidas utilizando 1,0 g de Florisil para 0,5 g de graviola in natura e eluição com 5 mL de acetonitrila. A miniaturização do procedimento de extração mostrou-se eficiente à extração dos agrotóxicos. A validação analítica foi realizada a partir dos parâmetros: linearidade e sensibilidade, mostrando-se linear com coeficientes de determinação superiores a 0,9995 e sensível no intervalo de concentração de 0,01-10 g mL-1; seletividade, a partir dos estudos de efeito matriz; exatidão e precisão, com valores de recuperação entre 79 -118% e coeficientes de variação na faixa de 1-15 % para os níveis de concentração 0,1; 0,25 e 0,5 g g-1 (n=5); e limites de detecção e quantificação nos intervalos de 0,01 - 0,25 g g-1 e 0,1 - 0,5 g g-1 , respectivamente. O material metal-orgânico (MOF) [(Nd0,9Eu0,1)2(DPA)3(H2O)3] foi testado como adsorvente para o processo de extração por MSPD e apresentou resultados satisfatórios de recuperação (78-87%), comparados àqueles obtidos com o Florisil.
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Wiberg, Kent. "Multivariate spectroscopic methods for the analysis of solutions". Doctoral thesis, Stockholm : Institutionen för analytisk kemi, Univ, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-110.
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Santos, Ruyanne Andreza Camilo. "Desenvolvimento de método para determinação de agrotóxicos (perturbadores endócrinos) em água". Universidade Federal de Sergipe, 2016. https://ri.ufs.br/handle/riufs/6050.
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Coordenação de Aperfeiçoamento de Pessoal de Nível Superior - CAPESThe water pollution causes changes in physical, chemical and biological water, which interfere with their quality, preventing its use for human consumption. Most chemical contaminants in surface water are related to industrial and agricultural sources. Since, with farming the Brazil pollute existing water resources making use of pesticides and fertilizers. This study aims to develop a fast and efficient method based on extraction techniques in solid phase (SPE) and high-performance liquid chromatography with UV detection in the ultraviolet and visible with diode array (HPLC UV-Vis / DAD) for the determination of pesticides, endocrine disruptors, epoxiconazole, fenarimol, fenbuconazole, flusilazole, flutriafol, and vinclozolin in water using biocarvões produced from agro-industry waste as an alternative sorbent for SPE. Tests with the analytes allowed the adjustment of the chromatographic conditions for simultaneous analysis of five selected pesticides. The optimal condition for the extraction of analytes was performed using 0.5 g of adsorbent to 50 mL of ultrapure water and eluted with 5 mL of acetonitrile. The biochar produced from coconut waste was tested as an adsorbent for the extraction by SPE and showed good recovery results between 75% ± 9 - 119 ± 12% for the concentration levels of 0.5 to 1 ug mL-1. The parameters studied to validate the method were: linearity and sensitivity, obtaining a good sensitivity and linear response with 0.9998 coefficients in the range of 0.01 to 10 ug mL-1; precision based on the precision of measurements (Intra) and intermediate precision (interday), obtaining results of 0.1-1%, 0.6-1%, respectively; accuracy with recovery values of 60 ± 37% - 117 ± 3% to the concentration levels of from 0.025 to 0.1 mg L-1 and 75 ± 9% - 119 ± 12% for levels 0.5 to 1 ug mL- 1 related to the biochar and C18, respectively. The LD 0.01 to 0.025 in range and LQ from 0.025 to 0.5 ug mL-1. The method developed was adequate for the determination of pesticides in water samples.
A poluição aquática provoca mudanças nas características físicas, químicas e biológicas das águas, as quais interferem na sua qualidade, impossibilitando o seu uso para o consumo humano. A maioria dos contaminantes químicos presentes em águas superficiais estão relacionados às fontes industriais e agrícolas. Uma vez que, com a atividade agrícola o Brasil polui os recursos hídricos existentes fazendo uso de agrotóxicos e fertilizantes. O presente trabalho tem como objetivo desenvolver um método rápido e eficiente baseado nas técnicas de extração em fase sólida (SPE) e cromatografia líquida de alta eficiência com detector espectrofotométrico na região do ultravioleta e visível com arranjo de diodos (HPLC UV-Vis/DAD) para a determinação dos agrotóxicos, perturbadores endócrinos, epoxiconazol, fenarimol, fenbuconazol, flusilazol, flutriafol, e vinclozolina, em água, utilizando biocarvões produzidos a partir de rejeitos de agroindústria, como adsorvente alternativo para a SPE. Testes realizados com os analitos permitiram o ajuste das condições cromatográficas para análise simultânea de cinco agrotóxicos selecionados. A condição ótima de extração dos analítos consistiu em utilizar 0,5 g do adsorvente para 50 mL de água ultrapurificada e eluição com 5 mL de acetonitrila. O biocarvão produzido a partir de rejeitos de coco foi testado como adsorvente para a extração por SPE e apresentou resultados satisfatórios de recuperação entre 75 ± 9% – 119 ± 12% para os níveis de concentração 0,5 a 1 μg mL-1. Os parâmetros estudados para a validação do método foram: linearidade e sensibilidade, obtendo-se uma boa sensibilidade e resposta linear com coeficientes de 0,9998 no intervalo de 0,01 a 10 μg mL-1; precisão com base nos estudos de repetibilidade (intradia) e precisão intermediária (interdia), obtendo-se resultados de 0,1–1%, 0,6–1%, respectivamente; exatidão com valores de recuperação entre 60 ± 37% – 117 ± 3%, para os níveis de concentração 0,025 a 0,1 μg mL-1 e 75 ± 9% – 119 ± 12% para os níveis 0,5 a 1 μg mL-1, com relação ao C18 e o biocarvão, respectivamente. O LD no intervalo de 0,01–0,025 e LQ 0,025-0,5 μg mL-1. O método desenvolvido se mostrou adequado para determinação de agrotóxicos em amostras de água.
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Pinto, Catarina Monteiro. "A Forensic (Chemical) Analysis of Portuguese Postage Stamps (1857-1909)". Master's thesis, 2017. http://hdl.handle.net/10316/83039.
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Dissertação de Mestrado em Química Forense apresentada à Faculdade de Ciências e TecnologiaA análise de selos, em particular de amostras pioneiras, tem sido objeto de alguns estudos, no entanto a natureza dos pigmentos ou corantes usados para imprimir os primeiros selos postais portugueses permanece desconhecida até aos dias de hoje. Além de não existirem estudos sobre os materiais utilizados para a sua produção, verifica-se também uma total ausência de referência aos corantes utilizados para colorir estes exemplares. Uma menção ao facto de que a 23 de abril de 1853, a Casa da Moeda Portuguesa recebeu uma caixa com tintas sugere a existência de algumas semelhanças entre esses e os selos postais britânicos. A partir de uma análise anterior, de alguns selos postais do Reino Unido sabe-se que o ácido carmínico, a cochonilha, (para os vermelhos) e a icónica mauveína (para lilás / roxo) foram utilizados no período de 1847 a 1901. Neste trabalho, foi realizado um estudo das tintas usadas para as cores vermelha, rosa, roxa e laranja num número selecionado de selos postais portugueses do período 1857-1909. Este estudo foi baseado em análises envolvendo uma variedade de técnicas (fluorescência de raios-X (XRF), espectroscopia ultra vioeta-visivel (UV-VIS), cromatografia liquida de alta eficiência - diode array detection - espectrometria de massa (HPLC-DAD-MS), fluorescência no estado estacionário e resolvida no tempo). Verificou-se que as tintas incluíram, entre outros, pigmentos inorgânicos, tais como o cinábrio (HgS), óxido de chumbo (Pb3O4), cromato de chumbo (PbCrO4), sulfeto de chumbo (PbS) e compostos orgânicos, entre os quais o ácido carmínico e a eosina Y. Este trabalho demonstrou ser possível a utilização de técnicas não-destrutivas para a identificação de algumas “moléculas da cor” envolvendo o XRF (para cinábrio, óxido de chumbo, cromato de chumbo, sulfeto de chumbo), UV-Vis (para ácido carmínico e eosina Y) e espectros de fluorescência, juntamente com rendimentos quânticos e tempos de vida (para eosina Y).
The analysis of postage stamps, in particular of pioneer samples, has been an object of some studies, however the nature of the pigments or dyes used to print the first Portuguese postage stamps remain unknown until today. Furthermore, the lack of studies on the materials used for their production, there is also a complete absence of reference to the dyes used to colour these specimens. A mention to the fact that on April 23, 1853, the Portuguese Coin House received a box with paints suggests some similarities between these and the British postage stamps.From a previous analysis some postage stamps of the United Kingdom it is known that Carminic Acid, cochineal, (for reds) and the iconic mauveine (for lilacs / purple) were used in them in the period from 1847 to 1901. In this work, a study has been made of the inks used for red, rose, purple and orange colours in a selected number of Portuguese postage stamps from the period 1857-1909. This is based on the analysis involving a variety of techniques (X-Ray Fluorescence (XRF), ultraviolet-visible (UV-VIS) spectroscopy, high performance liquid chromatography - diode array detection - mass spectrometry (HPLC-DAD-MS), steady and time resolved fluorescence). It was found that the inks included, among others, the inorganic pigments cinnabar (HgS), lead oxide (Pb3O4), lead chromate (PbCrO4), lead sulfide (PbS), and the organic compounds Carminic Acid and Eosin Y. This work demonstrated non-destructive analysis methods for identification of some molecules of colour involving the XRF (for cinnabar, lead oxide, lead chromate, lead sulfide), the UV-Vis (for Carminic Acid and Eosin Y) and fluorescence spectra, together with quantum yields and lifetimes (for Eosin Y).
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Hynštová, Veronika. "Monitoring flavonoidních látek a karotenoidů ve vybraných doplňcích stravy". Master's thesis, 2014. http://www.nusl.cz/ntk/nusl-179078.
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Dietary food supplements are among the most rapidly growing sectors in the food product industry. The majority of consumers trust in the safety and efficacy of these products. For these reasons is a quality control required and analytical methodologies for this must be used. For identification and quantitative analysis four flavonoids diosmin, hesperidin, rutin and troxerutin in food supplements was used HPLC/MS method. For identification and quantitative analysis three carotenoids betacarotene, lutein and zeaxanthin in food supplements was used HPLC/UV/ViS/DAD method. Separation of flavonoids was achieved on the column ZORBAX POROSHELL 120 EC-C18 (50 x 4,6 mm, 2,7 um) and separation of carotenoids on the column ZORBAX SB CN (75 x 4,6 mm, 3,5 um). The amount of flavonoids and carotenoids in tablets and capsules was determined altogether in 12 different commercial preparations.