Determination of tartaric acid in solid wine residues by capillary electrophoresis and indirect UV detection.

Tartaric acid, used in pharmaceuticals and industrial food preparation, is an important by-product of wine preparation. It is produced by wine factories in large quantities and cannot be rejected into the environment. Wineries precipitate tartaric acid using calcium hydroxide and then evaporate the mixture. The raw compact powder obtained, which contains calcium tartarate and a lot of other constituents (sugars, tannins, etc.) is sold to factories which purify tartaric acid. The different analytical methodologies which are used to determine the tartaric acid concentration in the solid wine residues are long and tedious (Goldenberg method, 14 samples per day). They also suffer from poor reproducibility. Some other methods use ion chromatography or solid Fourier transform IR, which are not currently used for such topics. We propose a capillary electrophoresis method, which not only is very quick (2 min of analysis) but also highly reproducible. Finally it provides very simple electropherograms. The intra-day and inter-day repeatability, the inter-person reproducibility and recovery were estimated. They demonstrate the ruggedness of this new method.