Um aparato para monitorar reações rápidas: um "stopped-flow" artesanal de baixo custo



Document title: Um aparato para monitorar reações rápidas: um "stopped-flow" artesanal de baixo custo
Journal: Quimica nova
Database: PERIÓDICA
System number: 000313266
ISSN: 0100-4042
Authors: 1



Institutions: 1Universidade Estadual de Maringa, Departamento de Quimica, Maringa, Parana. Brasil
Year:
Season: Sep
Volumen: 29
Number: 5
Pages: 1101-1105
Country: Brasil
Language: Portugués
Document type: Artículo
Approach: Experimental, aplicado
English abstract The modern stopped-flow reaction analyzer has shown high efficiency and flexibility, which provides outstanding sample economy with a dead-time of less than 1 ms. However the cost of the equipment imposes a serious restriction to many Brazilian scientists and teachers. In this work we describe the construction of a low-cost stopped-flow system coupled to a UV-Vis spectrophotometer. The performance of the system was checked by monitoring the kinetics of two reactions: the fading of phenolphthalein in aqueous alkaline solution and the chlorophyll a demetallation in acid medium. The apparatus showed reasonable efficiency with a dead-time of 0.3 to 0.5 s. The very good results obtained in these two illustrative processes show that the system is satisfactory for determining rate constants with mean reaction times ranging from seconds to minutes
Disciplines: Química
Keyword: Química analítica,
Instrumento de flujo detenido,
Cinética química,
Reacciones químicas
Keyword: Chemistry,
Analytical chemistry,
Stopped-flow instrument,
Chemical kinetics,
Chemical reactions
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