A flow-spectrophotometric method is proposed for the routine determination of
tartaric acid in wines. The reaction between
tartaric acid and
vanadate in
acetic media is carried out in
flowing conditions and the subsequent colored complex is monitored at 475 nm. The stability of the complex and the corresponding formation constant are presented. The effect of wavelength and pH was evaluated by batch experiments. The
selected conditions were transposed to a flow-injection analytical system. Optimization of several
flow parameters such as reactor lengths, flow-rate and injection volume was carried out. Using optimized conditions, a linear behavior was observed up to 1000 microg mL(-1)
tartaric acid, with a
molar extinction coefficient of 450 L mg(-1) cm(-1) and +/- 1 %
repeatability. Sample
throughput was 25 samples per hour. The flow-spectrophotometric method was satisfactorily applied to the quantification of TA in wines from different sources. Its
accuracy was confirmed by
statistical comparison to the conventional Rebelein procedure and to a certified analytical method carried out in a routine laboratory.
