title: Determination of the titratable acidity and the pH of wine based on potentiometric flow injection analysis.
abstract: A FIA system using a pH-sensitive detector based on a graphite/quinhydrone/silicone composite electrode was applied to determine sequentially the titratable acidity and the pH of wine, as well as the sum of calcium and magnesium ions. For all measurements the same FIA configuration was used employing different carrier solutions. The results for the determination of acidity and pH are in good agreement with those obtained by classical potentiometric titrations and by pH measurements using a conventional glass electrode. The standard deviation was less than 1.5% for both kinds of measurements and the sample volume was 150 μL. The method allows about 40 determinations of titratable acidity per hour and 30 pH measurements per hour. The titration method can be adjusted to the legal requirements in USA and Europe.
authors.affiliation: Analytical & Environmental Chemistry, Institute of Biochemistry, Greifswald University, Felix-Hausdorff-Str. 4, D-17487 Greifswald, Germany.
authors.forename: Katja
authors.initials: K
authors.lastname: Vahl
authors.forename: Heike
authors.initials: H
authors.lastname: Kahlert
authors.forename: Lisandro
authors.initials: L
authors.lastname: von Mühlen
authors.forename: Anja
authors.initials: A
authors.lastname: Albrecht
authors.forename: Gabriele
authors.initials: G
authors.lastname: Meyer
authors.forename: Jürgen
authors.initials: J
authors.lastname: Behnert
mesh_terms: D002118:Calcium / Q000032:analysis; D002138:Calibration; D003217:Conductometry / Q000295:instrumentation / Q000379:methods*; D004566:Electrodes; D017022:Flow Injection Analysis / Q000295:instrumentation / Q000379:methods*; D006108:Graphite / Q000737:chemistry; D006863:Hydrogen-Ion Concentration; D006873:Hydroquinones / Q000737:chemistry; D008274:Magnesium / Q000032:analysis; D011199:Potentiometry / Q000295:instrumentation / Q000379:methods*; D015203:Reproducibility of Results; D012828:Silicones / Q000737:chemistry; D014920:Wine / Q000032:analysis*
chemical_list: D006873:Hydroquinones; D012828:Silicones; D006108:Graphite; D008274:Magnesium; C004601:quinhydrone; D002118:Calcium