Call number: LD2668 .T4 1955 G38 / Master of Science

<p>New energy resources that can replace petroleum diesel are needed and biodiesel may be an excellent substitute. During storage and use, biodiesel can oxidize and form peroxides, leading to degradation of the fuel. It is therefore important to determine the peroxide content of the fuel. In this thesis the triphenylphosphine method, which involves GC-MS analysis has been compared to the standard iodometric method which involves titration with sodium thiosulfate. Working standards were made to see how well the iodometric method worked and also in order to make a calibration curve in GC-MS. Aged samples were then analyzed. The results showed that both methods gave good linearity and repeatability with limits of detection (LOD) and quantification (LOQ) of 0,06 mM and 0 17-0,65 mM respectively. However, the iodometric method seemed more circumstantial since it needed a lot of solvents and different reagents. The triphenylphosphine method was on contrary very simple to use and did not require too much preparation work. The latter also showed better reproducibility. In conclusions, both methods can be used in evaluating the peroxide content of biodiesel, but the triphenylphosphine method has the advantages of higher simplicity and better reproducibility.</p>

Analysis is a very important branch of chemistry, for it is such a practical part of the science. Analysis is itself divided into two parts. Qualitative analysis discovers what things are present in the material in question. Quantitative analysis then determines how much of each ingredient is present. This thesis considers a limited section of quantitative analysis. This thesis deals with the use of iodine in volumetric analysis, which is called either iodimetry or iodometry. In this type of analysis, the iodine is used in solution and reacts with some other material, also in solution, and takes up electrons. That is, the iodine is reduced, or electronized. In the second volume of the work referred to above the thirteenth chapter of some eighty pages is devoted to "Practical Methods of Iodometry."2 There are obviously many applications of this method. Our study was confined to the reaction of iodine with arsenic trioxide, concerning which Kolthoff says: "Standardization against arsenious oxide has proved to be best."3

New energy resources that can replace petroleum diesel are needed and biodiesel may be an excellent substitute. During storage and use, biodiesel can oxidize and form peroxides, leading to degradation of the fuel. It is therefore important to determine the peroxide content of the fuel. In this thesis the triphenylphosphine method, which involves GC-MS analysis has been compared to the standard iodometric method which involves titration with sodium thiosulfate. Working standards were made to see how well the iodometric method worked and also in order to make a calibration curve in GC-MS. Aged samples were then analyzed. The results showed that both methods gave good linearity and repeatability with limits of detection (LOD) and quantification (LOQ) of 0,06 mM and 0 17-0,65 mM respectively. However, the iodometric method seemed more circumstantial since it needed a lot of solvents and different reagents. The triphenylphosphine method was on contrary very simple to use and did not require too much preparation work. The latter also showed better reproducibility. In conclusions, both methods can be used in evaluating the peroxide content of biodiesel, but the triphenylphosphine method has the advantages of higher simplicity and better reproducibility.

Made available in DSpace on 2014-06-11T19:31:24Z (GMT). No. of bitstreams: 0 Previous issue date: 2007-10-30Bitstream added on 2014-06-13T19:20:21Z : No. of bitstreams: 1 tozo_gcg_dr_arafcf.pdf: 1418802 bytes, checksum: 299e470daf39de736e522b2d987e1a61 (MD5) / Universidade Estadual Paulista (UNESP) / A cefoxitina sódica (CAS 33564-30-6), antimicrobiano cefalosporínico, apresenta espectro de atividade contra microrganismos Gram-negativos mais amplo que as cefalosporinas mais antigas. Também é eficaz contra Proteus e Serratia indol-positivos, mostrando alta resistência à hidrólise por b-lactamases. Indicada no tratamento de peritonites e outras infecções intra-abdominais e intrapélvicas; sinusites, infecções ginecológicas, septicemias; endocardites; infecções do trato urinário, gonorréia não complicada, infecções do trato respiratório, ossos, articulações e pele. Apesar de este fármaco ser altamente estudado e pesquisado no que concerne à atividade antimicrobiana, farmacocinética e farmacodinâmica, há poucos estudos na literatura em relação ao desenvolvimento de metodologia analítica para esta cefalosporina. Desta forma, pesquisas envolvendo métodos analíticos são de fundamental importância e altamente relevantes para otimizar sua análise na indústria farmacêutica e farmpacia magistral de modo a garantir a qualidade do produto já comercializado. A proposta deste projeto foi desenvolver metodologias de análise para a cefoxitina sódica, fármaco comercializado no mercado médico-farmacêutico brasileiro. Foram desenvolvidos e validados métodos por CLAE com detector UV a 235 nm, com acetonitrila: água: ácido acético 5 M (22 : 78 : 1) como fase móvel e faixa de concentração de 20,0 à 30,0 μg/mL, tempo de retenção de 7,5 minutos. O coeficiente de correlação obtido foi de 0,9995 e a equação da reta y = 335,67x + 2391,9. O teste recuperação média obtido foi de 100,50%, com desvio padrão de 1,70%. O teor médio... / Sodium cefatoxin (CAS 33564-30-6), a cephalosporinic antibiotic, has a wider spectrum of activity against Gram-negative microrganisms than older cephalosporin. It is also efficient against the indol-positive Proteus and Serratia and has a high resistance to b- lactamases hydrolysis. Sodium cefatoxin is recommended for the treatment of peritonitis and other intra-abdominal and intra-pelvic infections; sinusitis, gynecological infections, septicemy, endocarditis; urinary tract infections, non-complicated gonorrhea, respiratory tract infections, bones, articulations and skin. Although this drug has been strongly studied and many researches have been developed about its antibiotics activity, pharmacokinetics and pharmacodynamics, there are few studies in the literature about the development of analytical methodology to this cephalosporin. Researches dealing with analytical methods are extremely important and highly relevant to optimize its analysis at the pharmaceutical industry and manipulation pharmacy, guaranteeing quality of the commercialized product. This project proposes the development of methodologies for analysis of sodium cefatoxin, a commercialized drug at the medical-pharmaceutical Brazilian market. Methods for CLAE with UV detector at 235nm were developed and validated with acetonitrile: water: acetic acid 5M (22: 78:1) as mobile phase and concentration range of 20.0 to 30.0 μg/mL, detention time of 7.5 minutes. The correlation coefficient obtained was 0.9995 and the line equation y = 335.67x + 2391.9. The medium recovery test was 100.50% with standard deviation of 1.70%. The medium content of sodium cefoxitin determined by CLAE... (Complete abstract click electronic access below)

Orientador: Hérida Regina Nunes Salgado / Banca: Marcos Antonio Segatto / Banca: Cristiane Masetto de Gaitani / Banca: Maria Virgínia Costa Scarpa / Banca: Thereza Christina Vessoni Penna / Resumo: A cefoxitina sódica (CAS 33564-30-6), antimicrobiano cefalosporínico, apresenta espectro de atividade contra microrganismos Gram-negativos mais amplo que as cefalosporinas mais antigas. Também é eficaz contra Proteus e Serratia indol-positivos, mostrando alta resistência à hidrólise por b-lactamases. Indicada no tratamento de peritonites e outras infecções intra-abdominais e intrapélvicas; sinusites, infecções ginecológicas, septicemias; endocardites; infecções do trato urinário, gonorréia não complicada, infecções do trato respiratório, ossos, articulações e pele. Apesar de este fármaco ser altamente estudado e pesquisado no que concerne à atividade antimicrobiana, farmacocinética e farmacodinâmica, há poucos estudos na literatura em relação ao desenvolvimento de metodologia analítica para esta cefalosporina. Desta forma, pesquisas envolvendo métodos analíticos são de fundamental importância e altamente relevantes para otimizar sua análise na indústria farmacêutica e farmpacia magistral de modo a garantir a qualidade do produto já comercializado. A proposta deste projeto foi desenvolver metodologias de análise para a cefoxitina sódica, fármaco comercializado no mercado médico-farmacêutico brasileiro. Foram desenvolvidos e validados métodos por CLAE com detector UV a 235 nm, com acetonitrila: água: ácido acético 5 M (22 : 78 : 1) como fase móvel e faixa de concentração de 20,0 à 30,0 μg/mL, tempo de retenção de 7,5 minutos. O coeficiente de correlação obtido foi de 0,9995 e a equação da reta y = 335,67x + 2391,9. O teste recuperação média obtido foi de 100,50%, com desvio padrão de 1,70%. O teor médio... (Resumo completo, clicar acesso eletrônico abaixo) / Abstract: Sodium cefatoxin (CAS 33564-30-6), a cephalosporinic antibiotic, has a wider spectrum of activity against Gram-negative microrganisms than older cephalosporin. It is also efficient against the indol-positive Proteus and Serratia and has a high resistance to b- lactamases hydrolysis. Sodium cefatoxin is recommended for the treatment of peritonitis and other intra-abdominal and intra-pelvic infections; sinusitis, gynecological infections, septicemy, endocarditis; urinary tract infections, non-complicated gonorrhea, respiratory tract infections, bones, articulations and skin. Although this drug has been strongly studied and many researches have been developed about its antibiotics activity, pharmacokinetics and pharmacodynamics, there are few studies in the literature about the development of analytical methodology to this cephalosporin. Researches dealing with analytical methods are extremely important and highly relevant to optimize its analysis at the pharmaceutical industry and manipulation pharmacy, guaranteeing quality of the commercialized product. This project proposes the development of methodologies for analysis of sodium cefatoxin, a commercialized drug at the medical-pharmaceutical Brazilian market. Methods for CLAE with UV detector at 235nm were developed and validated with acetonitrile: water: acetic acid 5M (22: 78:1) as mobile phase and concentration range of 20.0 to 30.0 μg/mL, detention time of 7.5 minutes. The correlation coefficient obtained was 0.9995 and the line equation y = 335.67x + 2391.9. The medium recovery test was 100.50% with standard deviation of 1.70%. The medium content of sodium cefoxitin determined by CLAE... (Complete abstract click electronic access below) / Doutor

The work studies the possibilities of the utilization of secondary raw materials produced by power industry. It addresses mainly the gypsum by-products and fluidized coal combustion ash. As for the secondary raw materials the content of sulphites is observed and the dependences of their transformation to sulphides via natural oxidation by air oxygen or by addition of adequate oxidant are studied. The work follows with describing the effect of sulphides contained in raw materials on the mechanical properties of composites prepared from several various matrices such as alumina or portland cement, lime or portland clinker. As for pure portland clinker the ability to retard the setting is also observed. The amount of contained sulphites is measured volumetrically via indirect titration of iodine surplus by sodium thiosulphate with the starch size as the indicator.