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Incorporacao e liberacao de resveratrol em hidrogeis polimericos / Resveratrol immobilization and release in polymeric hydrogelsMOMESSO, ROBERTA G.R.A.P. 09 October 2014 (has links)
Made available in DSpace on 2014-10-09T12:27:38Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:04:21Z (GMT). No. of bitstreams: 0 / Resveratrol (3, 4, 5-trihidroxiestilbeno) é um polifenol produzido por uma grande variedade de plantas em resposta ao estresse e encontrado predominantemente em cascas de uvas. Este princípio ativo apresenta vários benefícios à saúde, como a capacidade antioxidante, relacionada à prevenção de diversos tipos de câncer e do envelhecimento precoce da pele. No entanto, apresenta baixa biodisponibilidade quando administrado por via oral, o que torna interessante sua aplicação tópica. O principal objetivo deste trabalho foi a incorporação de resveratrol em hidrogéis poliméricos para obtenção de um sistema de liberação utilizado topicamente contra o desenvolvimento de desordens cutâneas, como o envelhecimento cutâneo e o câncer de pele. As matrizes poliméricas compostas por poli(N-vinil-2-pirrolidona) (PVP), poli(etileno glicol) (PEG) e ágar ou PVP e propano-1,2,3-triol (glicerina) e irradiadas a 20 kGy foram caracterizadas pelos ensaios de fração gel e intumescimento; sua biocompatibilidade preliminar foi avaliada in vitro por meio do ensaio de citotoxicidade utilizando o método de incorporação do vermelho neutro. Devido à baixa solubilidade do resveratrol em água, verificou-se o efeito da adição de 2% de etanol às matrizes. Todas as matrizes estudadas, contendo ou não álcool, apresentaram alto grau de reticulação, capacidade de intumescimento e não apresentaram toxicidade em ensaio preliminar de biocompatibilidade. Os dispositivos foram obtidos pela incorporação de resveratrol nas matrizes poliméricas, realizada de forma direta e indireta, ou seja, antes e após irradiação, respectivamente. Os dispositivos obtidos pelo método direto foram submetidos aos ensaios de fração gel, intumescimento e citotoxicidade e apresentaram-se semelhantes às respectivas matrizes. Os dispositivos contendo 0,05% de resveratrol obtidos pelo método direto e os dispositivos contendo 0,1% de resveratrol obtidos pelo método indireto foram submetidos ao ensaio de cinética de liberação durante 24 h. A quantificação do resveratrol liberado foi realizada por cromatografia líquida de alta eficiência (HPLC). Apenas os dispositivos obtidos pelo método indireto apresentaram capacidade de liberar o resveratrol incorporado, que apresentou capacidade antioxidante após liberação. / Dissertacao (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP
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Novel approaches for the chromatographic and electrophoretic separation of moleculesMeyer, Amanda R. January 1900 (has links)
Doctor of Philosophy / Department of Chemistry / Christopher T. Culbertson / High-performance liquid chromatography (HPLC) and capillary electrophoresis (CE) are two well-established analytical separation techniques that are continuously being adapted for performing distinctive separations and analyses of multitudes of complex and/or unique samples. Since their introduction, these techniques have been pivotal in the discovery, analysis, and understanding of a variety of samples and still prove to be key analytical tools for biological investigation.
Using these techniques, one can obtain a wide-range of valuable sample information from the hydrophobicity and molecular weights to size and charge distributions. Furthermore, these techniques allow for sample analysis, purification, and collection for additional sample analysis, such as mass spectrometry analysis. My doctoral dissertation encompasses the full scope of these two techniques and novel approaches for the investigation of distinct, relevant samples.
Described herein is the fabrication of glass microfluidic devices used for CE and their diversity for numerous investigations. Chapter 2 shows that the resolution of the photomasks used in microchip fabrication does not alter the separation efficiency of the devices, as the separations remain diffusion-limited. Using an in-house built capillary electrophoresis system, wheat proteins were separated more than 25% faster than previously reported in literature, and the electropherograms used for sample varietal identification. The fabrication of a robust, portable CE system capable of performing biological analysis in microgravity and hypergravity environments is also discussed. The need for and features necessary to achieve a reliable, robust, automated system is further described in Chapter 4. Isolation and analysis of the pea aphid (Acyrthosiphon pisum) salivary secretions was completed for the first time using HPLC. By altering the aphid environment and the sample treatment parameters, sample concentrations were increased above the limit of detection. Coupled with mass spectrometry, identification of pea aphid salivary proteins such as exopeptidase, angiotensin converting enzyme, and Buchnera proteins has been achieved. Finally, a simplified contact conductivity detection system for the detection of jurkat cells was developed that surpasses current, complex optical systems. The experiments described in this dissertation demonstrate novel approaches for the preparation, separation, analysis, and identification of a wide variety of common, and uncommon, samples.
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Multidimensional analytical techniques for the characterization of aliphatic polyestersPretorius, Nadine Odette 03 1900 (has links)
Thesis (PhD)--Stellenbosch University, 2013. / ENGLISH ABSTRACT: Complex polymers are defined by their distributive properties with respect to molecular weight, chemical
composition, functionality and molecular topology. As a result, polymer properties are very frequently
determined not only by one of these entities but by the correlation of two or more distributions. Aliphatic
polyesters are industrially implemented in high performance coatings, paints and varnishes. However, it is
typically difficult to correlate the resulting properties with the synthesis parameters as these polymers vary in
reactivity and application properties. Copolyester synthesis by direct polyesterification is often assumed to
produce randomized products due to the mechanisms involved in stepwise polymerization. The formation of
cyclic products by intramolecular reactions of hydroxyl (OH) and carboxylic (COOH) functional groups, sidereactions
such as transesterification, alcoholysis, and ester-ester interchange allow even further
randomization, enabling a highly complex system. Therefore, in addition to molecular weight distribution,
polyesters exhibit chemical composition, functionality type as well as branching distributions, classifying them
as complex polymeric systems. The different methods of polymer chromatography in combination with
sophisticated spectrometry techniques are useful tools for enabling the full description of the molecular
heterogeneity of these complex polyesters. The present study entails method development of different
modes of chromatography and mass spectrometry along with their combination, to facilitate the analysis of
the various distributions of two model polyester systems, phthalic and maleic anhydride, respectively, in
combination with propylene glycol. Gradient HPLC analysis enabled an oligomeric separation based on
chemical composition of the respective anhydride/propylene glycol samples. Its off-line coupling to MALDITOF
MS and ESI-QTOF MS revealed the presence of several distributions of varying endgroup functionality
type and molecular weight distributions at different intervals throughout the polymerization. In addition, online
gradient HPLC x size exclusion chromatography (2D-LC) was conducted to obtain the dual chemical
composition-molecular weight (CCD-MWD) distribution. The combination of the different coupling techniques
provided the opportunity to a more in-depth analysis of the structure-property relationships. / AFRIKAANSE OPSOMMING: Komplekse polimere word gedefinieer deur hul verdelings eienskappe ten opsigte van molekulêre massa,
chemiese samestelling, funksionaliteit en molekulêre topologie. Gevolglik, word hul eienskappe dikwels
bepaal deur nie net een van hierdie entiteite nie, maar ‘n korrelasie van twee of meer verdelings. Alifatiese
poliësters word industrieel geϊmplimenteer in hoë werkverrigting bestrykings, verwe en politoere, dog is dit
tipies moeilik om die uiteinde eienskappe met die verwante sintese parameters te korrelleer, aangesien die
polimere varieer in reaktiviteit en toepassingseienskappe. Ko-poliëster sintese vanaf direkte poliësterivering
word dikwels aanvaar om willekeurige produkte op te lewer as gevolg van die meganismes wat betrokke is
tydens trapgroei polimerisasie. Die produsering van sikliese produkte weens intra-molekulêre reaksies van
hidroksiel(OH) en karboksiel (COOH) verwante funksionele groepe, newereaksies soos transverestering,
alkoholise en ester-ester verwisseling, het verdere ewekansigmaking tot gevolg wat ‘n hoog
gekomplekseerde sisteem tot gevolg het. Benewens die molekulere massa verdeling, vertoon poliësters
dus chemiese samestelling, funksionaliteit tipe so wel as vertakkings verdeling wat hul as komplekse
polimeer sisteme klassifiseer. Die verskillende metodes van polimeer chromatografie in kombinasie met
gesofistikeerde spektrometriese tegnieke dien as nuttige bronne vir die volledige beskrywing wat betref die
molekulêre heterogeniteit van komplekse poliesters. Die huidige studie stel metode ontwikkeling van
verskillende modus van chromatografie, massa spektrometrie sowel as hul aaneenvoeging bekend, om die
die verskillende verdelings van twee model poliester sisteme, ftaal- en maleϊensuuranhidried onderskeidelik
in kombinasie met propileenglikol, suksesvol te analiseer. Gradiënt hoë-druk vloeistof chromatografie
(HPLC) analise het ‘n oligomeriese skeiding, gebaseer op die chemiese samestelling van die verskeie
anhidried /propileenglikol monsters, opgelewer. Die nie-gekoppelde skakeling met matriks-assisteerdelaser/
desorpsie-ionisasie tyd-van-vlug (MALDI-TOF) en elektron-sproei-ionisasie kwadrupool-tyd-van-vlug
(ESI-QTOF) massa spektrometrie het die teenwoordigheid van verskeie verdelings van varieërende
endgroep funksionaliteit tipe en molekulêre verdelings by verskillende intervalle tydens die polimerisasie aan
die lig gebring. Gekoppelde skakeling van gradient HPLC en grootte uitsluitings chromatografie is ook uitgevoer om die tweedelige chemiese samestelling-molekulere massa verdeling te bepaal. Aaneenvoeging
van die verskeie skakelings tegnieke het die geleentheid gebied om ‘n deeglike studie van die struktuureienskappe
verhoudinge suksesvol uit te voer.
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Evaluation of pressure- and electrodriven separation techniques for the determination of phenolic compounds in wineDe Villiers, A. J. (Andre Joubert) 03 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2000. / ENGLISH ABSTRACT: The phenolic content of wine is responsible for determining characteristics such as the
organoleptic qualities, colour stability, ageing properties and health-beneficial effects
associated with wine. The aim ofthis study was to investigate the possibilities offered by
capillary electrophoresis (CE) as an alternative separation technique to high performance
liquid chromatography (HPLC) for the analysis of polyphenols in wine. The complexity
of wine samples was the cause that neither technique was capable of a satisfactory singlestep
analysis of wine. Suitable sample preparation techniques such as Sephadex- and Sep-
Pak fractionation and ether extraction of wine polyphenols were investigated. These
techniques did not, however, prove to be universal. A novel form of sample preparation
namely a process analogous to lyophylization used to separate wine volatiles from nonvolatiles
was introduced.
The versatility of CE was further investigated in an attempt to eliminate the need for
sample preparation. The use of polyvinylalcohol (PVA) coated capillaries, micellar
electrokinetic chromatography (MEKC) and capillary gel electrophoresis (CGE) were
investigated in this regard. Although none of these techniques could offer conclusive
results, useful applications were forthcoming and routes for further investigation were
outlined. Liquid chromatography coupled to electro spray ionisation mass spectroscopy
(LC-ESI-MS) and capillary electrophoresis coupled to electro spray ionisation mass
spectroscopy (CE-ESI-MS) were compared for the analysis of polyphenols in wine.
While the latter technique could not produce sufficient separation compared to the
former, future development ofCE-ESI-MS should make it a powerful technique for these
analyses. / AFRIKAANSE OPSOMMING: Die fenoliese komponente in wyn speel 'n bepalende rol by eienskappe soos die
organoleptiese karakter, kleur stabiliteit, verouderingspotensiaal en gesondheids-voordele
wat met wyn geassosieër word. Die doel van hierdie projek was om ondersoek in te stel
na die potensiaal wat kapillêre elektroforese (CE, "capillary electrophoresis") as 'n
alternatiewe skeidingstegniek teenoor hoë druk vloeistof chromatografie (HDVC) vir die
analise van die polifenole in wyn bied. Die kompleksiteit van wyn monsters is van so 'n
aard dat 'n bevredigend enkelstap analise met geeneen van die tegnieke moontlik is nie.
Gepaste monster-voorbereidingstappe soos Sephadex- en Sep-Pak fraksionering asook
eter ekstraksie van die polifenole in wyn is ondersoek. Geeneen van die tegnieke was
egter universeel toepaslik nie. 'n Nuwe metode van monster-voorbereiding, naamlik 'n
proses analoog aan liofilisasie wat gebruik word om die wyn te skei in vlugtige en nievlugtige
komponente is gedemonstreer.
Die veelsydigheid van CE was gevolglik ondersoek in 'n poging om
monstervoorbereiding uit te skakel. Die gebruik van polyvinielalkohol-(pVA) bedekte
kapillêre, missellêre elektrokinetiese chromatografie (MEKC) en kapillêre gel
elektroforese (CGE, "capillary gel electrophoresis) is in hierdie verband ondersoek.
Alhoewel geeneen van hierdie tegnieke onweerlegbare resultate gelewer het nie, het
bruikbare toepassings hieruit voortgespruit en is die grondslag vir verdere navorsing gelê.
Vloeistof chromatografie gekoppel aan eIektrosproei ionisasie massaspektroskopie (LCESI-
MS) en kapillêre elektroforese gekoppel aan elektrosproei ionisasie massaspektroskopie
(CE-ESI-MS) is vergelyk vir die analise van polifenole in wyn. Alhoewel
laasgenoemde tegniek onvoldoende skeiding lewer vergeleke met eersgenoemde, behoort
toekomstige ontwikkelinge op die gebied van CE-ESI-MS dit 'n kragtige tegniek vir die
analise van hierdie monsters te maak.
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Amino acid analysis in wines by liquid chromatography : UV and fluorescence detection without sample enrichmentDouglas, C. A. (Claire Anne) 12 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2003. / ENGLISH ABSTRACT: In this study, the analysis of ammo acids usmg High Performance Liquid
Chromatography (HPLC) with pre-column derivatisation was optimised. The
derivatisation reagents include o-phthaldialdehyde (OPA), 9-
fluorenylmethylchloroformate (FMOC) and iodoacetic acid (IDA). Detection was
performed using UV and fluorescence in series. The developed method was utilised
for the analysis and quantitation of amino acids in eighteen wines. The application of
chemometric data evaluation was initiated. / AFRIKAANSE OPSOMMING: Hierdie ondersoek behels die optimisering van die aminosuuranalise deur gebruik te
maak van Hoë Druk Vloeistof Chromatografie (HDVC) in kombinasie met pre-kolom
derivatisering. Die derivativatiserings reagense sluit in o-phthaldialdehied (OPA), 9-
fluorenielmetielchloroformaat (FMOC) en jodoasynsuur (IDA). Deteksie is gedoen
deur gebruik gemaak van 'n ultraviolet (UV) en 'n fluorosensie detektor in serie. Die
metode sodoende ontwikkel is gebruik vir die analise en kwantifisering van aminosure
in agtien wyne. Die toepassing van chemometriese data evaluasie is ook geïnisieer.
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A study on the reversible photo-induced isomerisation of platinum(II) and palladium(II) complexes of the N,N-dialkyl-N’-acyl(aroyl)thioureas with reversed-phase HPLC separation from related rhodium(III), ruthenium(III) and iridium(III) complexesNkabyo, Henry Ane 04 1900 (has links)
Thesis (MSc)--Stellenbosch University, 2014. / ENGLISH ABSTRACT: See item for full text / AFRIKAANSE OPSOMMING: Sien item vir volteks
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Design, synthesis and characterization of ruthenium(II) and rhenium(I)complexes with functionalized ligands for photo-and electrochemi-luminescence, solvatochromism, molecular recognition and HPLCseparation studiesLi, Meijin., 李梅金. January 2006 (has links)
published_or_final_version / abstract / Chemistry / Doctoral / Doctor of Philosophy
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SFE Fractionation and RP-HPLC Characterization of Aquatic Fulvic AcidShao, Peimin 05 1900 (has links)
The Supercritical Fluid Extraction (SFE) technique was used to fractionate Suwannee River reference fulvic acid (FA). The fractions were characterized by gas chromatography (GC) and reversed-phase high performance liquid chromatography (RP-HPLC). A SFE fractionation method was developed using stepwise gradient of supercritical CO₂ and methanol. Three FA fractions were separated. The average mass recovery was 102% with the coefficient of variation of 2.8%. The fractionation dynamics and the difference in the ratios of UV absorption to fluorescence emission indicate the real fractionation of the FA. The HPLC chromatographic peak patterns and the spectra of the corresponding peaks were almost indistinguishable. The overall results of this research support the argument that FA exhibits polymer-like molecular structure.
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Radial Compression High Performance Liquid Chromatography as a Tool for The Measurement of Endogenous Nucleotides in BacteriaDutta, Probir Kumar 08 1900 (has links)
High performance liquid chromatography was used to measure ribonucleoside triphosphates in microbial samples. Anion exchange columns in a radial compression module were used to separate and quantify purine and pyrimidine ribonucleotides. Endogenous ribonucleoside triphosphates were extracted from Escherichia coli and pseudomonas aeruginosa using three different solvents, namely trifluorocetic acid (TFA; 0.5M), trichloroacetic acid (TCA; 6 per cent w/v) and formic acid (1.0M) Extracts were assayed for uridine 5'-triphosphate (ATP), and guanosine 5'-triphosphate (GTP) by using anion exchange radial compression high performance (pressure) liquid chromatography. The three extraction produres were compared for yield of triphosphates. E. coli, the TFA extraction procedure was more sensitive and reliable than TCA and formic acid extraction procedures, but , in P. aeruginosa, the best yields of ATP and GTP were obrained following extraction with TFA. Yields of UTP and CTP increased when extraction was performed in TCA. These data illustrate that different extraction produres produce different measures for different triphosphates, a point often overlooked.
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Chromatographic and Spectroscopic Studies on Aquatic Fulvic AcidChang, David Juan-Yuan 08 1900 (has links)
High Performance Liquid Chromatography (HPLC) was used to investigate the utility of this technique for the analytical and preparative separation of components of aquatic fulvic acids (FA). Three modes of HPLC namely adsorption, anion exchange and reversed phase were evaluated. Aquatic fulvic acids were either extracted from surface water and sediment samples collected from the Southwest of the U.S., or were provided in a high purity form from the USGS. On the adsorption mode, a major fraction of aquatic fulvic acid was isolated on a semipreparative scale and subjected to Carbon-13 NMR and FAB Mass Spectroscopy. Results indicated that (1) The analyzed fraction of fulvic acid contains more aliphatic than aromatic moieties; (2) Methoxy, carboxylic acids, and esters are well-defined moieties of the macromolecule; (3) Phenolic components of the macromolecules were not detected in the Carbon-13 NMR spectrum possibly because of the presence of stable free radicals. Results of the anion exchange mode have shown that at least three types of acidic functionalities in aquatic fulvic acid can be separated. Results also indicated that aquatic fulvic acid can be progressively fractionated by using subsequent modes of HPLC. Results of reversed phase mode have shown that (1) The fractionation of aquatic fulvic acid by RP-HPLC is essentially controlled by the polarity and/or pH of the carrier solvent system; (2) Under different RP-HPLC conditions aquatic fulvic acid from several locations are fractionated into the same major components; (3) Fulvic acid extracted from water and sediment from the same site are more similar than those extracted from different sites; (4) Cationic and anionic ion pair reagents indicated the presence of amphoteric compounds within the polymeric structure of fulvic acid. Each mode of HPLC provided a characteristic profile of fulvic acid. The results of this research provided basic information on the behavior of aquatic fulvic acids under three modes of HPLC. Such informations are prerequisite for further investigation by spectroscopic methods.
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