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Advisor(s)
Abstract(s)
In the present work a sequential injection system for the enzymatic determination of Image (−)malic acid in wines is described. The determination was based on the detection of NADH, formed by oxidation of Image -malate to oxaloacetate, catalysed by Image -malate dehydrogenase. A kinetic method was implemented by stopping the flow when a solution plug containing sample, NAD+ and enzyme reached the detector. The rate of reaction was measured by monitoring absorbance changes at 340 nm during a fixed period of time. A linear calibration curve (rate of reaction versus concentration) was obtained for concentrations of Image (−)malic acid between 0.01 and 0.15 g l−1. The determination rate was about 22 h−1 and samples were diluted 25 or 50 times before introduction to the system. Results obtained from 16 wine samples were comparable to those obtained by the reference method.
Description
Keywords
Sequential injection analysis Malic acid Kinetic enzymatic determination Wines
Citation
SEGUNDO, Marcela A. ; RANGEL, António O.S.S. - Kinetic determination of Image (−)malic acid in wines using sequential injection analysis. Analytica Chimica Acta. ISSN 0003-2670. Vol. 499, n.º1-2 (2003) p. 99-106
Publisher
Elsevier