Neste trabalho, propõe-se o desenvolvimento de procedimento analítico automático para determinação espectrofotométrica de microcistinas em águas empregando o processo de multicomutação em fluxo. O módulo de análise para implementar o procedimento analítico empregou um bomba de seringa para propulsão de fluído e válvulas solenóide para controlar a amostragem. A bomba de seringa foi construída no laboratório de Química Analítica, CENA/USP, onde foi empregado um motor de passo para fazer o deslocamento do êmbolo da seringa. Como detectores foram empregados, um fotômetro da Oriel Instrument e um fotômetro desenvolvido no laboratório de Química Analítica, CENA/USP, baseado em um fotodiodo da BURR-BRAWN e projetado para este procedimento. Uma cela de fluxo com caminho óptico de 40 mm e volume interno de 32 \'mü\'L, foi construída sob medida para permitir fácil acoplamento da fonte de radiação (LED) e dos fotodetectores, formando uma unidade compacta. O controle do sistema de fluxo, incluindo o motor de passo, foi executado por um microcomputador usando um software escrito em linguagem Quick Basic 4.5. Os sinais gerados pelos fotômetros em diferença de potencial eram convertidos para digital por um multímetro e enviados para o computador através da interface serial 232. O sistema proposto foi empregado para determinação de microcistinas em águas de rios e lagoas. A exatidão foi averiguada comparando com os dados obtidos empregando um equipamento ELISA. A faixa de concentração situada entre (0,1 e 0,8 \'mü\'gL-1) de microcistina indica que o sistema proposto pode ser usado em serviços de tratamento de águas onde o requerimento da ANVISA (Portaria n°518, 2004) deve ser alcançado / In this work, it was proposed the development of an automated analytical procedure based on multicommutation for the photometric determination of microcystins water. The flow module to implement the analytical procedure employed a syringe pump for solution propelling and solenoid valves for sampling control. The syringe pump was constructed in the laboratory CENA/USP, employed a step-motor to carry out the displacement of the syringe piston. As photodetectors was employed an Oriel Instrument photometer and a photometer developed in the laboratory CENA/USP based on a BURR-BRAWN photodiode and designed to be used in this procedure. A flow cell with optical pathlength of 40 mm and inner volume of 32 \'mü\'L was tailored to allow easily coupling of radiation source (LED) and photodetector, forming a compact unit. The control of the flow system, including the step-motor was performed by a microcomputer using a software wrote in Quick BASIC 4.5. The signals generated by the photometers in difference of potential were converted to digital by a digital multimeter and sent to the microcomputer through the serial interface 232. The proposed system was employed for the photometric determination of microcystins in water. Accuracy was assessed comparing the results with those obtained using a ELISA instrument. The concentration response (0,1 e 0,8 \'mü\'gL-1 microcystins) and limit of detection lower than 0.01 \'mü\'gL-1 microcystins, indicated that the proposed system can be used in plants of water treatment where the ANVISA requirement must be maintained

Thesis (M.S.M.E.)--University of Delaware, 2006. / Principal faculty advisor: James Glancey, Dept. of Bioresources Engineering. Includes bibliographical references.

In the flow distribution section of a paper machine, known as the head box, water is injected into the fiber suspension (stock) flow through a tee-mixer for more uniform production. This dilution process has two important requirements that must be fulfilled: (1) sufficient mixing so that the dilution flow spreads across the suspension flow and (2) that the injection flow rate not be so large to significantly alter the local head box flow rate. The objective of this research was to find a combination of velocity ratio and tee mixer geometry that lead to the injection flow being well mixed into the stock flow, but at the same time, the injection should not cause the total flow rate to change by more than 1%. Velocity ratios of 0.25, 0.75, 1.33, 1.5 and 2.25 were examined for four different cases of tee mixer geometries using the CFD software Fluent. Two of the cases had added contractions located near the injection point, while the other two cases had a more standard geometry with no added complexities. The pressure drop across the injection point was also measured. Mixing was qualitatively measured by simulating the injection of a passive tracer into the dilution flow. All of the results indicated that the case where the contraction was located after the injection showed the most promising results with quality mixing and lower flow rates. The cases without added contractions showed poor mixing for lower velocity ratios, and for higher velocity ratios, the flow rates were too large. The cases with contractions showed similar mixing, but the outlet flow rates produced were lower when the contraction was located after the injection instead of before it. A velocity ratio of 0.25-0.75 for the mixers with contractions produced acceptable flow rates and sufficient mixing. The simulations also showed that the static pressure for the contraction cases were nearly identical throughout the majority of the pipe. For both contraction cases the pressure drop across the injection increased with increasing injection flow rate. When the contraction was located before the injection, a pressure drop of 16% was calculated. A pressure drop of 18% to 20% across the injection resulted when the contraction was located after the injection.

Thesis (Ph. D.)--University of Washington, 2003. / Vita. Includes bibliographical references (leaves 110-117).

In sugar industry, determination of invert sugars (fructose and glucose) provides information about the quality, process control and characteristics of the produced fructose and glucose syrups. Determination of invert sugar is also important for wine industries. In wine process, fructose and glucose are converted to ethanol by fermentation and the type of wine is designated by the amount of invert sugar remained. Fast and reliable invert sugar detection techniques are required to check the quality of wine throughout the fermentation process. Cathecholamines (eg. dopamine and epinephrine) are diol containing compounds which play important roles in higher animals&rsquo / physicomotor activities, learning, sleeping, memory and immune system. They also affect brain functions. Inbalances in dopamine level in brain result in a number of psychiatric disorders, particularly schizophrenia and Parkinson disease. Catecholamines are present in relatively high amounts in drugs. Many efforts have been made to develop analytical procedures for their rapid, simple and accurate determination. For these reasons, catecholamine quantification is important in the field of pharmacy and medicine. Boronic acids interact with 1,2 or 1,3-diol containing compounds, such as fructose, glucose and dopamine, rapidly and reversibly. Hence, boronic acids are used as the recognition moeity in the construction of photoinduced electron transfer (PET) fluorophores specific for saccharides and catecholamines. In this study, a flow injection analysis system has been developed for the rapid and selective recognition of fructose and glucose in wine and in commercial sugar syrups / dopamine and epinephrine in pharmaceutical injections by using dansylaminophenyl boronic acid (DAPB) which is a fluorescent PET molecule.

Thesis (Ph. D.)--University of Washington, 1997. / Vita. Includes bibliographical references (leaves [96]-100).

Thesis (M.S.)--University of Texas at El Paso, 2009. / Title from title screen. Vita. CD-ROM. Includes bibliographical references. Also available online.

Thesis (M.S.M.E.)--University of Delaware, 2006. / Principal faculty advisor: Suresh G. Advani, Dept. of Mechanical Engineering. Includes bibliographical references.

Made available in DSpace on 2016-06-02T20:36:11Z (GMT). No. of bitstreams: 1 1421.pdf: 745167 bytes, checksum: 22ae6edd66dd06f360360df924ce1905 (MD5) Previous issue date: 2005-07-25 / Universidade Federal de Sao Carlos / Methods for the determination of minoxidil in commercial samples are presented. The minoxidil is a pharmaceutical whose dilation blood vessel property is used in the treatment of the Arterial Hypertension and in the treatment of the Alopecia Areata. Two commercial samples were analyzed, the Regaine® (Pharmacia, U.S.A.) and the Neoxidil® (Galderma, Brazil) both are solutions of topical use containing 2% of minoxidil (20 mg mL-1) in a mixture of ethanol and propilenoglicol as vehicle. Four proposals for the determination of minoxidil in commercial samples were considered. The first one was the titrimetric determination of minoxidil in pharmaceutical formulations using potassium permanganate in which it was possible to quantify the amount of minoxidil in the commercial samples by classical titration. In other method it was used a spectrophotometric titration for the determination of minoxidil in pharmaceutical formulations using potassium permanganate, in which the decrease in the absorbance at 550 nm. The third method was the use of the flow injection analysis (FIA) for the determination of minoxidil in pharmaceutical formulations using potassium permanganate as redox reagent, in which the decrease of the absorbance of the carrying potassium permanganate solution in acidic media was monitored spectrophotometricaly at 550 nm under controlled temperature at 50 OC. Finally it was considered a method that consists in a potenciometric titration of minoxidil with potassium dichromate, in which the potential difference between is monitored a platinum electrode (working) and a saturated calomel electrode (reference) at 60 OC. / No presente trabalho são apresentados métodos para a determinação minoxidil em amostras comercias. O minoxidil é um fármaco que, devido à sua propriedade vasodilatadora é usado no tratamento da Hipertensão Arterial e no tratamento da Alopécia Areata. Foram analisadas duas amostras comerciais, o Regaine® (Pharmacia, EUA) e o Neoxidil® (Galderma, Brasil), sendo ambos soluções de uso tópico contendo 2% de minoxidil m/v (20 mg mL-1), em uma mistura de etanol e propilenoglicol como veículo. Foram propostos quatro métodos para a determinação do analito em amostras comerciais. O primeiro foi a determinação titrimétrica de minoxidil em formulações farmacêuticas usando permanganato de potássio na qual foi possível quantificar o minoxidil presente nas amostras comerciais por volumetria, apresentando como resultado do teste de adição e recuperação os valores de 94,5 e 95,3 % para o Neoxidil® e o Regaine® respectivamente. O segundo método foi o emprego da titulação espectrofotométrica para a determinação de minoxidil em formulações farmacêuticas usando permanganato de potássio, no qual foi usado um espectrofotômetro para acompanhar o decréscimo da absorbância em 550 nm, apresentando 102,8 % para o Neoxidil® e 101,0 % para o Regaine® resultados obtidos no teste de adição e recuperação. O terceiro método foi o uso de da xi análise por injeção em fluxo (FIA) para a determinação de minoxidil em formulações farmacêuticas usando permanganato de potássio como reagente redox, no qual foi monitorado o decréscimo da absorbância da solução transportadora de permanganato de potássio em maio ácido por um espectrofotômetro em 550 nm, com temperatura controlada em 50 OC, freqüência de amostragem de 32 determinações/hora, limite de detecção de 8,95 x 10-6 mol L-1 e adição e recuperação de 104,7 a 106,4 % para o Neoxidil® e o Regaine® respectivamente. Para finalizar foi proposto um quarto método que consiste na determinação titrimétrica com detecção potenciométrica de minoxidil usando dicromato de potássio como reagente, no qual foi medido o potencial no ponto final da titulação por um eletrodo de platina (trabalho) e por um eletrodo de calomelano saturado empregado como referência a 60 OC e adição e recuperação de 98,7 a 97,4 % para o Neoxidil® e o Regaine® respectivamente.

Made available in DSpace on 2016-06-02T20:36:20Z (GMT). No. of bitstreams: 1 1931.pdf: 3271266 bytes, checksum: ac7d5d17977332c6c74ea7b27253652c (MD5) Previous issue date: 2008-02-18 / Financiadora de Estudos e Projetos / A multicommutation flow system for the spectrophotometric determination of hypochlorite in bleaching products using a cell with pathlength of 1 cm is proposed in this work. In this system, N,N-diethyl-p-phenylenediamine (DPD) reacts with hypochlorite and the product was monitored at 515 nm. The analytical curve for hypochlorite was linear in concentration range from 2.68x10-5 to 1.88x10-4 mol L-1 (2 to 14 mg L-1) with a detection limit of 6.84x10-6 mol L-1 (0.51 mg L-1). The sampling rate of 45 h-1 and a relative standard deviation of 1.4 % (n = 10), were obtained. The recovery of this analyte ranged from 97% to 102.5%. The results found for six bleaching products using the proposed multicommutated flow system agreed with those data obtained using a reference method (iodometric titration) at the 95 % confidence level. A multicommutation flow system for the spectrophotometric determination of chlorine in water samples using a cell with 100 cm of pathlength is also proposed in this work. In this system, dichloridrate orto-Tolidine (3,3-dimethyl bencidine) reacts with chlorine and the product was monitored at 438 nm. The analytical curve for hypochlorite was linear in the concentration range from 1.34x10-6 to 2.01x10-5 mol L-1 (0.1 to 1.5 mg L-1) with a detection limit of 9.4x10-8 mol L-1 (7.0x10-3 mg L-1). The sampling rate of 45 h-1 and a relative standard deviation of 1.0 % (n = 15), were obtained. The recovery of this analyte ranged from 96.8% to 104.6%. The results found for six water samples from São Carlos city using the proposed method agreed with those data obtained using the method used by CETESB (Kit DPD colorimetric) at the 95 % confidence level. The long pathlength optic system is composed by amorphous fluorpolymeric Teflon AF2400tube with a 100 cm of length and refraction index smaller than the water one that was used as wave guide, aiming to minimize radiation losses. Finally, flow system involving multicommutation was developed to increase analytical features, decrease the reagents consumption and residual production. / A determinação espectrofotométrica de hipoclorito em alvejantes, utilizando análise por injeção em fluxo e multicomutação é proposta neste trabalho. Nesse sistema, sulfato de N,N-dietil-p-fenilenodiamina (DPD) reage com hipoclorito, sendo o produto resultante monitorado em 515 nm. O sistema proposto apresentou curva analítica linear no intervalo de concentração de hipoclorito de 2,68x10-5 a 1,88x10-4 mol L-1 (2 a 14 mg L-1) usando-se a célula de 1 cm de caminho óptico, com um limite de detecção de 6,84x10-6 mol L-1 (0,51 mg L-1), freqüência analítica de 45 determinações por hora e desvio padrão relativo de 1,4 % (n = 10). A recuperação do analito variou de 97% a 102,5%. Os resultados obtidos para hipoclorito, em seis amostras de alvejantes, de acordo com o procedimento proposto, foram concordantes com aqueles obtidos quando se empregou um método padrão (titulação iodométrica), com um nível de confiança de 95 %. Em outra etapa, foi proposta a determinação de cloro em águas de abastecimento por espectrofotometria em fluxo com longo caminho óptico (100 cm) e multicomutação. Nesse sistema, dicloridrato de orto-tolidina (3,3 -dimetilbenzidina) reage com cloro, sendo o produto resultante monitorado em 438 nm. A curva analítica foi linear no intervalo de concentração de cloro de 1,34x10-6 a 2,01x10-5 mol L-1 (0,1 a 1,5 mg L-1), com um limite de detecção de 9,4x10-8 mol L-1 (0,007 mg L-1). A freqüência analítica foi de 45 determinações por hora e desvio padrão relativo de 1,03 % (n = 15). A recuperação do analito variou de 96,8% a 104,6%. Os resultados obtidos para cloro, em seis amostras de águas de abastecimento da cidade de São Carlos-SP, de acordo com o procedimento proposto, foram concordantes com aqueles obtidos quando se empregou o método utilizado pela CETESB (DPD colorimétrico), com um nível de confiança de 95 %. O sistema de longo caminho óptico é constituído por um tubo de Teflon AF2400fluorpolímero amorfo, de um metro de comprimento, com índice de refração inferior ao da água. Esse tubo serve como guia de onda, minimizando, assim, perdas de radiação. Os sistemas propostos propiciaram melhor desempenho analítico, diminuindo o consumo de reagentes e, principalmente, a produção de resíduos.