Made available in DSpace on 2014-12-17T14:16:22Z (GMT). No. of bitstreams: 1 TeresaCEDR.pdf: 519764 bytes, checksum: 16c1c0bd407e1a2f0c58712123711127 (MD5) Previous issue date: 2008-09-23 / The ethanol is the most overused psychoactive drug over the world; this fact makes it one of the main substances required in toxicological exams nowadays. The development of an analytical method, adaptation or implementation of a method known, involves a process of validation that estimates its efficiency in the laboratory routine and credibility of the method. The stability is defined as the ability of the sample of material to keep the initial value of a quantitative measure for a defined period within specific limits when stored under defined conditions. This study aimed to evaluate the method of Gas chromatography and study the stability of ethanol in blood samples, considering the variables time and temperature of storage, and the presence of preservative and, with that check if the conditions of conservation and storage used in this study maintain the quality of the sample and preserve the originally amount of analyte present. Blood samples were collected from 10 volunteers to evaluate the method and to study the stability of ethanol. For the evaluation of the method, part of the samples was added to known concentrations of ethanol. In the study of stability, the other side of the pool of blood was placed in two containers: one containing the preservative sodium fluoride 1% and the anticoagulant heparin and the other only heparin, was added ethanol at a concentration of 0.6 g/L, fractionated in two bottles, one being stored at 4?C (refrigerator) and another at -20?C (freezer), the tests were performed on the same day (time zero) and after 1, 3, 7, 14, 30 and 60 days of storage. The assessment found the difference in results during storage in relation to time zero. It used the technique of headspace associated with gas chromatography with the FID and capillary column with stationary phase of polyethylene. The best analysis of chromatographic conditions were: temperature of 50?C (column), 150?C (jet) and 250?C (detector), with retention time for ethanol from 9.107 ? 0.026 and the tercbutanol (internal standard) of 8.170 ? 0.081 minutes, the ethanol being separated properly from acetaldehyde, acetone, methanol and 2-propanol, which are potential interfering in the determination of ethanol. The technique showed linearity in the concentration range of 0.01 and 3.2 g/L (0.8051 x + y = 0.6196; r2 = 0.999). The calibration curve showed the following equation of the line: y = x 0.7542 + 0.6545, with a linear correlation coefficient equal to 0.996. The average recovery was 100.2%, the coefficients of variation of accuracy and inter intra test showed values of up to 7.3%, the limit of detection and quantification was 0.01 g/L and showed coefficient of variation within the allowed. The analytical method evaluated in this study proved to be fast, efficient and practical, given the objective of this work satisfactorily. The study of stability has less than 20% difference in the response obtained under the conditions of storage and stipulated period, compared with the response obtained at time zero and at the significance level of 5%, no statistical difference in the concentration of ethanol was observed between analysis. The results reinforce the reliability of the method of gas chromatography and blood samples in search of ethanol, either in the toxicological, forensic, social or clinic / O etanol ? a droga psicoativa mais utilizada de forma abusiva em todo o mundo, isso faz dele uma das principais subst?ncias requisitadas em exames toxicol?gicos na atualidade. O desenvolvimento de um m?todo anal?tico, a adapta??o ou implementa??o de um m?todo conhecido, envolve um processo de valida??o que estima sua efici?ncia na rotina do laborat?rio e a credibilidade do m?todo. A estabilidade ? definida como a capacidade da amostra do material manter o valor inicial de uma medida quantitativa por um per?odo definido dentro de limites espec?ficos quando armazenados sob condi??es definidas. Este trabalho teve como objetivo avaliar o m?todo de Cromatografia em fase gasosa e estudar a estabilidade do etanol em amostras de sangue, considerando as vari?veis tempo e temperatura de armazenamento, bem como a presen?a de conservante e, com isso verificar se as condi??es de conserva??o e armazenamento utilizadas neste estudo mant?m a qualidade da amostra e preservam a quantidade inicialmente presente do analito. Foram coletadas amostras de sangue de 10 volunt?rios para avalia??o do m?todo e para o estudo da estabilidade do etanol. Para a avalia??o do m?todo, parte das amostras foi adicionada de concentra??es conhecidas de etanol. No estudo da estabilidade, a outra parte do pool de sangue foi colocada em dois recipientes: um contendo o conservante fluoreto de s?dio 1% e o anticoagulante heparina e no outro somente heparina, foi adicionado etanol na concentra??o de 0,6 g/L, fracionado em dois frascos, sendo um armazenado a 4?C (geladeira) e outro a -20?C (freezer). As an?lises foram realizadas no mesmo dia (tempo zero) e ap?s 1, 3, 7, 14, 30 e 60 dias de armazenamento. A avalia??o considerou a diferen?a dos resultados durante o armazenamento em rela??o ao tempo zero. Foi utilizada a t?cnica de head space associada ? cromatografia em fase gasosa com detector de ioniza??o de chama e coluna capilar com fase estacion?ria de polietilenoglicol. As melhores condi??es cromatogr?ficas de an?lise obtidas foram: temperatura de 50?C (coluna), 150?C (injetor) e 250?C (detector), com tempo de reten??o para o etanol de 9,107 ? 0,026 e para o t-butanol (padr?o interno) de 8,170 ? 0,081 minutos, sendo o etanol separado adequadamente do acetalde?do, acetona, metanol e isopropanol, que s?o potenciais interferentes na determina??o do etanol. A t?cnica mostrou linearidade no intervalo de concentra??o de 0,01 e 3,2 g/L (y = 0,8051x + 0,6196; r2 = 0,999). A curva de calibra??o apresentou a seguinte equa??o da reta: y = 0,7542x + 0,6545, com um coeficiente de correla??o linear igual a 0,996. A recupera??o m?dia foi de 100,2%, os coeficientes de varia??o da precis?o intraensaio e interensaio apresentaram valores de no m?ximo 7,3%, o limite de detec??o e quantifica??o foi de 0,01 g/L e apresentou coeficiente de varia??o dentro do permitido. O m?todo anal?tico avaliado no presente trabalho demonstrou ser r?pido, pr?tico e eficiente, atendendo satisfatoriamente aos objetivos do trabalho. O estudo da estabilidade demonstrou diferen?a menor que 20% na resposta obtida nas condi??es de armazenamento e per?odo estipulados, comparada com a resposta obtida no tempo zero e, ao n?vel de signific?ncia de 5%, nenhuma diferen?a estat?stica na concentra??o de etanol foi observada entre as an?lises. Os resultados obtidos refor?am a confiabilidade do m?todo de cromatografia em fase gasosa e das amostras de sangue na pesquisa de etanol, seja na ?rea toxicol?gica, Forense, social ou cl?nica

At low speeds, older cyclists have a higher risk of losing balance and having an accident on a pedelec than younger cyclists. A stability assistance system with an electric motor acting on the handlebars can provide steering assistance and help stabilize a pedelec. However, the steering interventions can possibly affect the cyclist and his riding experience. Using a steer assisted pedelec, this study investigates the influence of these interventions on the cyclist and his riding experience at low speeds.