Automatic spectrophotometric procedure for the determination of tartaric acid in wine employing multicommutation flow analysis process

In the present work, an automatic flow procedure for the determination of tartaric acid in red wine without previous sample treatment is described. The flow system comprising three-way solenoid valves designed to implement the multicommutation flow analysis process. Under microcomputer control, the analytic procedure could be accomplished automatically without any intervention of the operator. The spectrophotomer method was based on the tartaric acid reaction with sodium vanadate. Intending to prove the effectiveness of the propose procedure, a set of red wine samples was analyzed. To permit accuracy assessment, wine samples were also analyzed using the OIV reference method. Applying the paired t-test between results obtained, no significant difference at 90% confidence level was observed. Other profitable features, such as a linear relationship between 0.50 and 10.0 g l−1 tartaric acid (r = 0.9998), a 2.1% coefficient of variation (n = 8), a sampling frequency of 28 determinations per hour, and a reagent consumption of 0.15 mg sodium vanadate per determination were also achieved.