Multicommutated flow system for spectrophotometric L(+)lactate determination in alcoholic fermented sugar cane juice using enzymatic reaction

• Autor(a) principal: Kronka,Eloisa A. Mocheuti
• Data de Publicação: 2005
• Outros Autores: Paim,Ana Paula S., Tumang,Cristiane A., Latanze,Rodrigo, Reis,Boaventura F.
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Journal of the Brazilian Chemical Society (Online)
• Texto Completo: http://old.scielo.br/scielo.php?script=sci_arttext&pid=S0103-50532005000100007
• topic: L(+)lactate determination; multicommutation; sugar cane juice; enzymatic reaction

A multicommutation flow system for the spectrophotometric determination of L(+)lactate in alcohol fermented sugar cane juice is proposed. The spectrophotometric method was based on the L(+)lactate conversion to pyruvate plus hydrogen peroxide by the lactate oxides enzyme, followed by reaction with peroxidase enzyme and condensation between 4-chlorophenol and 4-aminoantipyrine. The flow system network comprised three three-way solenoid valves controlled by a microcomputer that running a software wrote in Quick BASIC 4.5 provided also facilities to perform data acquisition. After optimization of system parameters, a set of alcohol fermented juice was analyzed to prove the procedure feasibility. Samples with concentration raging from 5.0 to 100.0 mg L-1 L(+)lactate were analyzed using a 150 UI lactate oxidize and 200 UI peroxidase enzymatic solution. Other advantageous features such as a relative standard deviation of 2% (n = 15) for a typical sample containing 38.5 mg L-1 L(+)lactate; an analytical throughput of 36 determination per hour; and a low reagent consumption 1.0 mug 4-chlorophenol and 0.1 mug 4-aminoantipyrine per determination were also achieved.