Kinetic determination of L(-)malic acid in wines using sequential injection analysis

Marcela A. Segundo, António O. S. S. Rangel*

*Corresponding author for this work

Research output: Contribution to journalConference articlepeer-review

13 Citations (Scopus)


In the present work a sequential injection system for the enzymatic determination of L(-)malic acid in wines is described. The determination was based on the detection of NADH, formed by oxidation of L-malate to oxaloacetate, catalysed by L-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 340nm during a fixed period of time. A linear calibration curve (rate of reaction versus concentration) was obtained for concentrations of L(-)malic acid between 0.01 and 0.15gl-1. The determination rate was about 22h-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.
Original languageEnglish
Pages (from-to)99-106
Number of pages8
JournalAnalytica Chimica Acta
Issue number1-2
Publication statusPublished - 4 Dec 2003
Event9th International Conference on Flow Analysis - Geelong, Australia
Duration: 10 Feb 200314 Feb 2003
Conference number: 9


  • Kinetic enzymatic determination
  • Malic acid
  • Sequential injection analysis
  • Wines


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