Made available in DSpace on 2014-10-09T12:41:42Z (GMT). No. of bitstreams: 0 / Made available in DSpace on 2014-10-09T14:07:07Z (GMT). No. of bitstreams: 0 / O poli(ε-caprolactona) (PCL) é um polímero biocompatível e biodegradável, aprovado pelo Food and Drug Administration (FDA) para ser usado como biomaterial. Diversos estudos utilizando sua forma linear ou ramificada têm demonstrado resultados promissores para seu uso no desenvolvimento de dispositivos médicos e em aplicações na área farmacêutica. O objetivo deste trabalho foi utilizar o PCL com estrutura estrelada (PCLE) para obter microesferas biorreabsorvíveis. Primeiramente realizou-se a avaliação das propriedades físico-químicas do PCLE por meio da cromatografia de permeação em gel (GPC), ressonância magnética de prótons (1H-RMN) e carbono (13C-RMN), calorimetria exploratória diferencial (DSC) e espectrometria por infravermelho com transformada de Fourier (FT-IR). A avaliação toxicológica do PCLE foi obtida por meio do ensaio de citotoxicidade utilizando células CHO-K1 e o corante vital 5-(3-carboximethoxifenil)-2-(4,5-dimetiltiazolil)-3-(4-sulfofenil) tetrazolium e do acoplador de elétrons fenazine metilssulfato (MTS/PMS). O ensaio de biodegradação foi conduzido em pH 7,4 na presença de lipase a 37 ºC. Após essas análises o PCLE foi utilizado para preparação de esferas por meio de emulsão complexa A/O/A. O PCLE foi caracterizado como um polímero de baixa massa molar, com dispersão de tamanho unimodal e cerca de 68,8 % de suas moléculas apresentaram estrutura estrelada com três braços. Em relação às propriedades térmicas o PCLE apresentou temperatura de fusão de 57,3 ºC e temperatura de transição vítrea de -54,3 ºC. A avaliação da citotoxicidade mostrou que o extrato de PCLE é compatível com o metabolismo celular. As microesferas obtidas a partir do PCLE, por emulsão A/O/A apresentaram polidispersão de tamanho. / Dissertação (Mestrado) / IPEN/D / Instituto de Pesquisas Energeticas e Nucleares - IPEN-CNEN/SP

Orientador: Telma Teixeira Franco / Dissertação (mestrado) - Universidade Estadual de Campinas, Faculdade de Engenharia Quimica / Made available in DSpace on 2018-08-02T19:11:38Z (GMT). No. of bitstreams: 1 Todorovic_Zoran_M.pdf: 2109964 bytes, checksum: a9300d59d70b5fdcbb2831ea8b7e1899 (MD5) Previous issue date: 2002 / Resumo: A biocompatibilidade, biodegradabilidade e o fato de ser um polimero catiônico bioadesivo fazem a quitosana um material atrativo para inúmeras aplicações na área biotecnológica, agrícola, farmacêutica e médica. As quito sanas com massas molares baixas e os oligômeros têm maiores perspectivas nas últimas duas áreas. O objetivo deste projeto de pesquisa foi a obtenção de polimeros com massa molar média reduzida devido à ação da enzima papaína. Empregando papaína livre e em forma imobilizada a redução da massa molar da quito sana foi estudada. Quitina foi utilizada como suporte para imobilização da papaína e para imobilização da proteína modelo albumina de soro bovino. Experimentos com todos estes materiais foram realizados para estudar os efeitos da modificação da quito sana. Os experimentos foram conduzidos em reatores batelada com pH e temperatura controlados. Soluções da quito sana (1 %) foram preparadas utilizando ácido lático ou ácido acético para solubilização. Duas técnicas para determinação da massa molar da quito sana foram utilizadas. Em primeiro lugar, a visco simetria foi empregada sendo esta a técnica mais comum para investigação de redução da massa molar. Redução da viscosidade de soluções de quitosana foi associada à diminuição da massa molar média. Outro método utilizado para a determinação de massas molares foi a cromatografia de permeação em gel, que é considerado um método relativo de determinação de massa molar, pois necessita de padrões dos polimeros para a construção de uma curva padrão. A massa molar determinada por estes dois métodos é dependente do tamanho da molécula (diâmetro). O método absoluto de determinação da massa molar com detector de espalhamento de luz também foi utilizado. Este detector conectado on-line com cromatografia de permeação em gel fornece dados absolutos da massa molar média. Luz espalhada de diferentes partes da molécula do polimero em diferentes ângulos geram o valor correto da massa molar sem utilização dos padrões. Os resultados mostraram o efeito superior na redução da massa molar utilizando papaína em comparação com outros materiais utilizados. Esta redução da massa molar média é rápida e acentuada nos primeiros minutos da reação, em comparação com a continuação do processo / Abstract: Biocompatibility, biodegradability and the fact of being bioadhesive polycationic polymer make chitosan an attractive material for various applications in agricultural and biotechnological, pharmaceutical and medical fields. Chitosans with lower molecular weights and oligomers OOve major perspectives in the last two fields. An objective of this project of research was the production of polymers with reduced molecular weight due to the action of enzyme papain. Applying papain in the free and immobilized form the reduction of molecular weight of chitosan was studied. Chitin was used as a support for the immobilization of papain and for the immobilization of model protein bovine serum albumin. Experiments with all these materiais were realized to study the effects of modification of chitosan. Experiments were run using batch reactors at controled pH and temperature. Chitosan solutions (1 %) were prepared using lactic acid or acetic acid for solubilization. Two different techniques were used for determination of molecular weight of chitosan. First viscosimetry was applied as the most common technique used for investigation of reduction of molecular weights. Reduction of viscosity of chitosan solutions is associated with the reduction of molecular weight. The other method used for determination of molecular weights is gel permeation chromatography toot is considered a relative method of determination of molecular weights as it requires polymeric standards for the construction of the standard curve. Molecular weight determined by these two methods is dependant of the molecular size (diameter). Absolute method of determination of molecular weights through measurements with detector of light scattering was aIso applied in this studies. This detector connected on-line with gel penneation chromatography provides us with the absolute molecular weights. This method does not require standards measuring the light scattered from different parts of the polymeric molecule in different angles generating in this way the correct value of molecular weight. Results show the superior effect of papain on the reduction of molecular weight compared to the other materiais used. This reduction of molecular weight is fast, pronounced in the :fust minutes of the reaction in comparison with the continuation of the process / Mestrado / Desenvolvimento de Processos Químicos / Mestre em Engenharia Química

Erythromycin (ERY) is a macrolide antibiotic which is used in the treatment of acne vulgaris.Acne is a common skin condition that occurs when the sebaceous glands and hair shafts become infected by the bacteria Propionibacterium acnes. Acne is a chronic condition that may last for years and the severity of the effects of the disease on patients is often undermined especially in third world countries where more emphasis is placed on other more life-threatening diseases. It may cause considerable physical and emotional distress to sufferers along with the possibility of permanent scarring. Although use of topical ERY formulations is not the first line of treatment it has proven to be effective in treating inflammation of skin and skin structures cause by the responsible bacteria. To-date there are a variety of vehicles which are used in preparing topical ERY formulations namely ointment and gel bases, alcoholic solutions and pledgets. All the gel formulations on the market contain hydroxypropyl cellulose, alcohol and water along with the active ingredient(s). However, some gel formulations contain propylene glycol in addition to these excipients an example being Emgel®. Propylene glycol has been shown to affect the penetration of topically applied drugs through the skin suggesting that it would be highly likely that those formulations which contain propylene glycol may release more ERY into the skin following application. With this in mind, two ERY gel formulations were produced which contained different percentages of propylene glycol. According to the FDA guidelines, pharmacokinetic measurements in blood, plasma and/or urine of topical dermatological drug products are not feasible to document bioequivalence since the active ingredient(s) in topical formulations is/are not intended to be absorbed into the systemic circulation and in addition, concentrations in extracutaneous biological tissues would generally not be measurable. This limits determination of bioavailability and assessment of bioequivalence of such products to pharmacodynamic measurements, clinical trials and dermatopharmacokinetic (DPK) measurements such as tape stripping (TS) and microdialysis (MD).TS is a sampling technique which involves sequential removal of layers of the stratum corneum using strips of adhesive tape. This technique has found increasing use in DPK studies for investigation of drug kinetics in the skin following the application of a topical formulation. The technique has also been used as a diagnostic tool in assessing the quality of the stratum corneum in diseased skin. In the current research study, the tape stripping technique was used to investigate the pharmaceutical/biological availability of topical gel formulations containing ERY. MD is another DPK sampling technique which has been used to determine the amount of a topically applied drug that penetrates through the stratum corneum to reach deeper tissues of the skin. The in vivo sampling technique involves the insertion of microdialysis probes beneath the skin surface in the dermal tissue and allows for real-time sampling of the analyte at its target site. Recently in vitro MD has also been successfully used to assess the pharmaceutical availability of a topical corticosteroid, mometesone furoate, from topical formulations. Based on this work, microdialysis was used to determine the pharmaceutical availability of ERY from gel formulations which were developed for use in this research. The results of the pharmaceutical availability of ERY from in vivo tape stripping studies and the in vitro microdialysis studies were compared to establish correlation between the data. Pharmaceutical equivalence and bioequivalence data obtained from the respective studies on the gel formulations were investigated by statistical analysis of the data generated from both the in vitro and in vivo experiments. In summary the objectives of this research were: 1. To develop and validate a high performance liquid chromatography method suitable to analyse ERY concentrations obtained from in vitro microdialysis studies and in vivo tape stripping studies. 2. To prepare two different ERY gel formulations with different percentage content of propylene glycol. 3. To determine the pharmaceutical availability of ERY from two different gel formulations using in vitro microdialysis. 4. To develop and validate a tape stripping technique which could be used to determine percutaneous penetration and bioequivalence of the gel formulations. 5. To compare in vitro microdialysis and in vivo tape stripping data and attempt to establish a correlation between the two different approaches.

Scaffolds are proteins with high conformational stability, allowing us to implement multiple mutations into specific parts of the protein. Even with these mutations, the structural integrity of the protein is maintained as well as its physical-chemical properties. These mutations give the specific scaffold new properties. In most cases it is the binding specificity towards previously chosen target. The biggest advantages of scaffolds are their small size, stability, low-cost manufacturing, and easiness of preparation. Scaffold utilized in this thesis is unique for having two binging surfaces designed on which it can be mutated. Each of those two surfaces can be separately mutated to develop a binging site for two different proteins. In our case these mutations led to binding two nonidentical receptors of a human cytokine. Mutations are made with a use of yeast display, one of the methods of directed evolution. The main focus of this thesis is changing an expression system of the binding proteins from the yeast system to a bacterial one, their production and purification followed by characterization of those binding proteins using biophysical methods. These methods were used to evaluate structural and thermal stability, and binding affinity to both receptors of the beforementioned binding proteins....

In den letzten 15 Jahren wurde in einigen Mittelgebirgsregionen Zentraleuropas ein regional un-terschiedlich starker Anstieg der Konzentration gelösten organischen Kohlenstoffes (DOC) in Oberflächengewässern festgestellt. Besonders betroffen von dieser Entwicklung sind für die Trink-wasserproduktion genutzte Talsperren. Durch den erhöhten DOC-Gehalt wird die Trinkwasser-aufbereitung nicht nur kostenintensiver, sondern bekommt auch zunehmend Probleme bei der Wahrung der Trinkwasserqualität. Die Quellen des DOC sind in den Einzugsgebieten befindliche Moore und hydromorphe Nassstandorte. Die Ursachen für den in den vergangenen Jahren doku-mentierten Mehraustrag sind äußerst komplex und beinhalten sowohl klimatische als auch nut-zungsbedingte Veränderungen. Ziel der vorliegenden Arbeit ist, den Charakter des DOC näher zu bestimmen, um die für die Wasseraufbereitung problematischen Fraktionen zu benennen und Ansatzpunkte für regulierende Maßnahmen aufzuzeigen. Die Charakterisierung erfolgte an einem LC-OCD-System (Liquid Chromatography – Organic Carbon Detection) am Beispiel der drei Tal-sperrensysteme Muldenberg, Carlsfeld (Westerzgebirge) und Fláje (Osterzgebirge, Tschechien). Die Talsperren weisen unterschiedliche DOC-Gehalte auf. Die Ergebnisse zeigen, dass der DOC aller Untersuchungsgebiete sowohl in den Zuflüssen, dem Talsperrenwasser bzw. Rohwasser als auch dem Reinwasser der Wasserwerke von Huminstoffen dominiert wird. DOC-Schwankungen sind folglich auf Schwankungen der Huminstoffkonzentrationen zurückzuführen. In den Zuflüs-sen treten die höchsten Huminstoffkonzentrationen während der Schneeschmelze im Frühjahr und bei Starkniederschlägen im Sommer und Herbst auf. Niedrige Konzentrationen sind an Bo-dengefrornis oder Trockenphasen im Sommer gebunden. In den Talsperren tritt im Sommer eine Schichtung der Huminstoffe auf, bei der an der Oberfläche durch photolytischen Abbau niedrige-re Konzentrationen und in Abhängigkeit von der Talsperrentiefe durch die Einschichtung der Zuflüsse am Grund höhere Konzentrationen auftreten. Die Verteilung im Winter ist allein von der Einschichtung der Zuflüsse abhängig. Die Verteilung der Building Blocks (Huminstoffhydrolysate) ist im Sommer der der Huminstoffe entgegengesetzt, da sich beim photolytischen Abbau von Hu-minstoffen Building Blocks bilden. Während der Zirkulationen sind die Konzentrationen der Hu-minstofffraktionen im gesamten Tiefenprofil gleich. In den Talsperren Muldenberg und Carlsfeld wurde im Untersuchungszeitraum unter Berücksichtigung der technischen Gegebenheiten und anderer Wassergütekriterien der optimale Rohwasserentnahmehorizont (niedrigstmögliche Hu-minstoffkonzentration) gewählt. In der Talsperre Fláje könnte die Rohwasserqualität durch Instal-lation eines schwenkbaren Entnahmerohres erheblich verbessert werden. In den Wasserwerken sind die Huminstofffraktionen mit abnehmender Molekülgröße schwieriger zu entfernen. Die relativ niedermolekularen Building Blocks sind die am schwersten entfernbaren DOC-Bestandteile. Auf Grundlage mathematischer Beziehungen zu SAK254 bzw. DOC wurde ein Programm (DOCQuaC – DOC-Quality Calculator) entwickelt, mit dessen Hilfe die Huminstofffraktionen über diese Grundparameter ermittelt werden können. Neben der Fraktionsquantifizie-rung besteht im Programm die Möglichkeit zur Berechnung der Eliminierungsleistung, so dass beispielsweise nach der Durchführung einer Maßnahme zur Verbesserung der DOC-Entfernung eine unmittelbare Aussage über den Effekt auf die Fraktionen vorliegt. / For the last 15 years a change of Dissolved Organic Carbon (DOC) has been taking place in surface waters of Middle European Highlands. The degree of this increase is regionally dependent. The reasons as well as the consequences of this development are of high complexity. The changes are expressed in an increase of middle DOC values and, additionally, an increase of annual changes. Reservoirs, used for drinking water production, are particularly affected, because the heightened DOC content increases the costs for drinking water treatment, and currently it is not possible to maintain a good drinking water quality. The main DOC source are peat bogs, situated in the catchments. The cause of the increasing DOC output from peat bogs are very complex and contain changes as well in climate as in land use. The aim of this presented dissertation was to gain more information about the character of DOC, so that those fractions can be determined which are problematically to remove inside the waterworks. On that base it should be possible to find some starting points for more regulating measures. The analytical characterisation was carried out by the help of a LC-OCD-System (Liquid Chromatography – Organic Carbon Detection), exemplary for the reservoir systems Muldenberg, Carlsfeld (Western Ore Mountains) and Fláje (Eastern Ore Mountains, Czech Republic). Although the DOC concentrations are very different in the reser-voirs, it was always dominated by humic substances, namely as well in the tributaries, as in the raw and treated water. Thus changes in the DOC concentration are due to changes in the concen-tration of humic substances. In spring and summer occur the highest concentrations of humic substances in the tributaries. Low concentrations are linked with frost in winter or dry periods in summer. In the reservoirs in summer a stratification of humic substances shapes up, with lower concentration near the water surface (caused by photolytical degradation) and accordingly higher concentration near the ground (layering of influxes). Distribution in winter only depends on the layering of the influxes. In summer the concentration of Building Blocks (humic substance hydro-lysates) is opposite to that of humic substances, because of the creation of Building Blocks at the photolytical degradation. During circulation the concentration of all humic substance fractions are equal in each reservoir layer. In the reservoirs Muldenberg and Carlsfeld, a further optimisation of the raw water withdrawal horizon is not possible. In the reservoir Fláje the raw water could be much improved by installing a movable withdrawal device. With decreasing molecular size the elimination of the humic fractions gets more difficult in the waterworks. Most difficult to eliminate are Building Blocks. On the basis of the mathematical cor-relation between humic fractions and the SAC254 and DOC a program (DOCQuaC – DOC-Quality Calculator) has been developed, which enables die calculation of humic concentrations by enter-ing these general parameters. In addition to the calculation of the concentrations it is possible to calculate the elimination capacity for the humic fractions. Thus the effects of measures on the humic fractions, which could be done for optimisation of the elimination capacity, can be imme-diately observed.

The degradation of wool keratin under conditions relevant to those of wool dyeing was investigated using the techniques of gel permeation chromatography (GPC), ion exchange gel chromatography, and amino acid analysis. Physical testing of the treated and untreated wool was also carried out to determine the physical changes occurring, parameters used being percentage elongation at the break, and the breaking strain of the fibre. Samples of wool keratin were immersed in various aqueous solutions at 1000C for 24 hours and the filtered, aqueous, oxidised extracts were analysed* The solutions used varied only in the dye, or dye intermediate present in the treatment solution. All treatment baths contained 10% owf 1.02 x 10 -2 MSulphuric VI acid; 10%owf 7.04x 10 -3 MSodium sulphate VI ; A 100 :1 liquor ratio was used in each case. Some of the dye intermediates showed a marked catalytic effect, particularly in their effect on breaking strain, a decrease of 40% in some cases. The GPC profiles of the extracted proteins were examined in detail and compared against previous workers' results. An explanation of the behaviour of the dyes and intermediates was proposed. The amino acid composition data of the extracted and fractionated proteins were compared against various morphological components extracted by other workers, as was the total gelatin obtained from each treatment. / Science Research Council

Αντικείμενο της παρούσας διατριβής αποτέλεσε η μελέτη μιγμάτων αλειφατικών/αρωματικών πολυεστέρων. Αρχικά υπήρχε η πρόθεση να επικεντρωθούμε στη μελέτη της βιοαποικοδόμησης μίγματος ενός αλειφατικού και ενός αρωματικού πολυεστέρα. Για τη διερεύνηση όμως της αναμειξιμότητάς τους εστιάσαμε στην έμμεση μελέτη του μοριακού προσανατολισμού μονοαξονικά εφελκυσμένων μιγμάτων αλειφατικών/αρωματικών πολυεστέρων, με τη χρήση πολωμένων φασμάτων δόνησης. Πιο συγκεκριμένα, εξετάστηκε η σύγχρονη παρουσία σ’ ένα μόνο πολωμένο φάσμα Raman της μη-συμβατικής συμπεριφοράς της δόνησης τάσης της χαρακτηριστικής ομάδας του καρβονυλίου (C=O) των αρωματικών πολυεστέρων με την αντίστοιχη συμβατική συμπεριφορά της ίδιας ομάδας των αλειφατικών πολυεστέρων. Μετά από πολλές προσπάθειες διαφόρων παρεμφερών μιγμάτων στα οποία παρουσιάστηκαν διάφορα προβλήματα, κυρίως αναμειξιμότητας, καταλήξαμε στο μίγμα του βιοαποικοδομήσιμου αλειφατικού πολυεστέρα L-PLA με τον αρωματικό πολυεστέρα PBT. Παρασκευάστηκαν φιλμ των ομοπολυμερών L-PLA και PBT καθώς και του μίγματος L-PLA/PBT, με ανάμιξη των συστατικών σε τήγμα και στη συνέχεια μορφοποίησή τους σε υδραυλική θερμοπρέσα. Για τον προσδιορισμό των θερμικών ιδιοτήτων των υλικών χρησιμοποιήθηκε η τεχνική Διαφορικής Θερμιδομετρίας Σάρωσης (DSC). Δοκίμια των ομοπολυμερών και του μίγματος εφελκύστηκαν μονοαξονικά σε θερμοκρασίες μεγαλύτερες από τη μετάβαση υάλου τους και ο προσανατολισμός τους εκτιμήθηκε με τη χρήση πολωμένων φασμάτων Raman. Σε κάθε περίπτωση, επειδή παρά τις πολλές προσπάθειες δεν ήταν δυνατό κυρίως και πάλι λόγω προβλημάτων αναμειξιμότητας να συνεχιστεί μια τέτοια μελέτη και στο επίπεδο της βιοαποικοδόμησης ενός αλειφατικού και ενός αρωματικού πολυεστέρα, αποφασίσαμε να συνεχίσουμε με ένα αναμείξιμο σε κάθε αναλογία μίγμα, ενός βιοαποικοδομήσιμου και ενός μη-αποικοδομίσιμου πολυμερούς. Το μίγμα αυτό των πολυμερών ήταν το PCL/PVC με το οποίο και συνεχίστηκε και ολοκληρώθηκε η παρούσα διατριβή εξειδίκευσης. Το ενδιαφέρον επικεντρώθηκε στη μελέτη μιγμάτων PCL/PVC διαφόρων συστάσεων, δύο πολυμερών τα οποία είναι αναμίξιμα σε όλο το εύρος των αναλογιών τους. Το ομοπολυμερές του αλειφατικού πολυεστέρα PCL και τα μίγματα που προέκυψαν μελετήθηκαν ως προς τις θερμικές τους ιδιότητες και χαρακτηρίστηκαν φασματικά με Raman. Επιπλέον, επιχειρήθηκε η μελέτη της βιοαποικοδόμησης τόσο της PCL όσο και των μιγμάτων της με PVC, μετά από εμβάπτιση σε φυσιολογικό ορό για χρονικό διάστημα άνω των 3 μηνών. Για τον προσδιορισμό των θερμικών ιδιοτήτων των μιγμάτων PCL/PVC και του ομοπολυμερούς PCL χρησιμοποιήθηκε η τεχνική DSC, στη συνέχεια χαρακτηρίστηκαν με τη δονητική φασματοσκοπία Raman ενώ ακολούθησαν πειράματα Χρωματογραφίας Διαπιδύσεως μέσω Πηκτής (GPC) και Δυναμικής Σκέδασης Φωτός (DLS) ώστε να προσδιοριστεί η βιοαποικοδόμηση των υλικών. Η βιοποικοδόμηση των PCL/PVC και κατ’ επέκταση της PCL μελετήθηκε υπό διαφορετικές συνθήκες (θερμοκρασίας, χρόνου, συγκέντρωσης) και σε διαφορετικό βαθμό. / The aim of this dissertation was the study of aliphatic/aromatic copolyesters. At the beginning, the main purpose was to investigate the biodegradation behavior of an aliphatic/aromatic polyester blend. In order to examine the miscibility of the two polymers comprising the blend we have studied the molecular orientation of melt blends utilizing polarized vibrational spectroscopy. After plenty of essays on resembling blends and due to the problems that we have faced (mainly miscibility problems) we decided to study the polymer blend of the biodegradable aliphatic polyester Poly(L-lactic acid) (L-PLA) and the aromatic polyester Poly(butylene terephthalate) (PBT). In particular, the interest centered to the peculiar and unexpected behavior of the C=O stretching carbonyl Raman band of the aromatic polyesters (in case PBT) comparing to the corresponding conventional behavior of the aliphatic polyesters, (in case L-PLA). L-PLA/PBT blends were prepared through reaction extrusion (melt mixing). Films prepared by melt pressing have been uniaxially hot drawn. Polarized laser Raman spectroscopy has been used to estimate the molecular orientation of drawn films of L-PLA and PBT homopolymers and L-PLA/PBT polymer blends. The crystallization behavior of the samples was investigated by using a differential scanning calorimeter (DSC). Finally, the polymers L-PLA and PBT have found to be partially miscible so we took the decision of studying another totally miscible blend consisted of PCL and PVC, a mixture of an aliphatic biodegradable polyester and a non-biodegradable thermoplastic polymer. Blends of PCL and PVC are under development with various potential applications in view, including controlled delivery of agrichemicals, and it is important to investigate their biodegradation behavior. The thermal properties of the homopolymer PCL and PVC blends were investigated under nitrogen by using DSC. Samples of the homopolymer PCL and PCL/PVC blends were placed in glass bottles with serum for more than 3 months. Raman Spectroscopy, Gel Permeation Chromatography and Dynamic Light Scattering have been used to estimate the biodegradation of the samples.

Natural organic matter (NOM) is a diverse blend of decomposed animal and plant material found in different natural water sources. Due to its large and complex structure, NOM is difficult to both remove and characterize in water. Therefore, there is a need to separate NOM into its components before it can be characterized. The aim of this project was to fractionate NOM through a novel size exclusion chromatography (SEC) composite (poly (styrene-divinyl benzene) (PS-DVB) and Polysilsesquioxane (PSQ)) packed column. Raw and final water samples from Mid-Vaal (MV), Olifantspoort (LO), Mtwalume (MT) and Preekstoel (P) were investigated. Poly (styrene-divinyl benzene) (PS-DVB) and polysilsesquioxane were both synthesized and optimized at various temperatures, compositions and time periods. An end-capping material such as hexamethyldisilizane (HMDS) was added on the PSQ to prevent active silanol groups on the polysilsesquioxane (PSQ) from reacting with active sites of NOM (our analyte). The E-PSQ (end-capped PSQ) and PS-DVB materials were packed in eight different SPE cartridges first, before the materials could be packed in the SEC column. This packing was done to check for the best mass composition of the E-PSQ and PS-DVB. From the obtained SPE results, both the EPSQ and PS-DVB were packed in one SEC/GPC column at a ratio of 1:1 in order to form the composite hybrid material. The packed SEC column was connected to an HPLC instrument and various column efficiency tests were evaluated. The results for the test of interactions with acidic compounds implied that the column can be used for the acidic analytes such as those forming NOM composition (humic acids, fulvic acids) and the column had minimum silanol groups. For hydrophobic interactions the stationary phase strength was different to that of the commercial columns and it could selectively elute molecules based on their different masses. The steric selectivity test showed that the stationary phase could separate and distinguish between molecules with similar hydrophobicity and structure but different shapes (o-terphenyl and triphenylene). The Hydrogen bonding capacity (HBC) test showed that the column had minimum silanol groups and the end-capping was successful on the E-PSQ. After fractionation of all the water samples, the MT raw showed NOM peaks around 1.8 mins, 3.4 mins and 5.3, and the final showed NOM peaks around 1.8 mins and 5.5 mins. The Mid-Vaal (MV) raw and final samples shows NOM peaks at around 1.8 mins and 6 mins. The Preekstoel (P) final water had one NOM peak at around 1.8 mins and raw samples had two NOM peaks around 1.8 mins and 6 mins. / Chemistry / M. Sc. (Chemistry)

Environmental and health aspects of road materials have been discussed for a long time, mostly regarding bitumen and bitumen fumes. However, just a few studies on other types of road materials have been reported. In this doctoral study, two types of materials, asphalt release agents and bituminous sealants, were investigated with regard to chemical characterization and emission profiles. Besides conventional test methods, solid-phase microextraction (SPME) technique was applied for emissions profiles screening and quantitative analysis. General description of main characteristics of asphalt release agents and bituminous sealants is given, and a comprehensive state-of-the-art on SPME technique is presented, especially on methodologies for analyzing mono- and polycyclic aromatic hydrocarbons (MAHs and PAHs) in different sample matrices. In the experimental study, chemical characterization of the two material types was performed using conventional methods, including fourier transform infrared spectroscopy - attenuated total reflectance (FTIR-ATR), gel permeation chromatography (GPC), mass spectrometry (MS) and gas chromatography – mass spectrometry (GC-MS). General patterns regarding functional groups and molecular weight distribution were studied. In the case of asphalt release agents, more detailed information on chemical compositions, especially the contents of MAHs and PAHs, was obtained. General information on emission proneness of asphalt release agents was obtained using thermogravimetric analysis (TGA) and MS. Using headspace(HS)-SPME and GC-MS, emission profiles of asphalt release agents were characterized at different temperatures, whereas the profiles of bituminous sealants were obtained solely at room temperature. The results presented were used for ranking the materials with regard to degree of total emission as well as emission of hazardous substances. The applicability of HS-SPME for quantitative analysis of MAHs in asphalt release agents and emulsion-based bituminous sealants was investigated. The use of a surrogate sample matrix was concerned, and experimental parameters influencing the HS-SPME procedure, such as equilibration and extraction time, as well as effects of sample amount and matrices, were studied. The methods were evaluated with regard to detection limit, accuracy as well as precision. Different calibration approaches including external calibration, internal calibration and standard addition were investigated. The determination of MAHs in asphalt release agents and emulsion-based bituminous sealants using HS-SPME-GC-MS was conducted. / QC 20100913

This diploma work is aimed determination of strobilurine pesticide in barly, malt and berr. Identifikation of strobilurine was made according to mass spectra library and base of commercialy standard. The next quantifikation in samples was made. The work consist of three main parts refer about problems. In therotical part is the method of plant, grown protection. This part is about pesticides and their fission, history and effects. In experimental part is method for determination strobilurine. In part results and discussion are all result and data in tables a graphs. At the end is sumed up result this work.