Neste trabalho foi desenvolvido um procedimento empregando multicomutação em fluxo e reação enzimática para determinação espectrofotométrica de L(+)lactato proveniente da fermentação alcoólica de vinho (mosto de cana de açúcar) O método espectrofotométrico foi baseado na reação com a enzima lactato oxidase, seguida pela reação com a enzima peroxidase e posterior condensação entre 4-clorofenol e 4 -aminoantipirina. O módulo de análise foi constituído por um conjunto de três válvulas solenóides, bomba peristáltica, espectrofotômetro e microcomputador equipado com interface de controle. Um programa escrito em QuickBASIC 4.5 foi desenvolvido para controlar as válvulas solenóides e realizar aquisição de dados. Amostras na faixa de concentração de 5,0 a 100,0 mg L -1 de L(+)lactato foram analisadas usando uma solução contendo 150 UI de lactato oxidase e 200 UI de peroxidase. Outras características analíticas tais como, desvio padrão relativo de 2% (n = 15) para uma amostra típica contendo 38,5 mg L -1 de L(+)lactato; freqüência de amostragem de 36 determinações por hora; e baixo consumo de reagentes (1,0 µg de 4-clorofenol e 0,1 µg 4-aminoantipirina) por determinação também foram obtidas.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 µg 4-chlorophenol and 0.1 µg 4-aminoantipyrine per determination were also achieved.
A multicommutated flow procedure for simultaneous spectrophotometric determination of nonstructural carbohydrates and reducing sugar in forage materials is proposed. Determination of both analytes was based on the neucroine method after acid hydrolysis of nonstructural carbohydrates. Results for both analytes presented the following features: no significant difference at 90% confidence level when compared with reference method, linear response between 0.2 to 0.8% (w/v) (r = 0.999); relative standard deviations of < 2.0% (n = 10), and sampling rate of 32 determinations per hour.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.