DETERMINATION OF TITRATABLE ACIDITY OF WINES AND TOTAL ACIDITY OF VINEGARS BY DISCONTINUOUS FLOW-ANALYSIS USING PHOTOMETRIC END-POINT DETECTION

The titratable acidity of white and red wines and the total acidity of vinegars were determined using the flow-based titration technique, discontinuous flow analysis with photometric end-point detection. A flow cell was used which had a low-volume mixing chamber fitted with a high-speed stirrer. Detection of the end-point was achieved using a light emitting diode and photodiode incorporated into the flow cell. A sample throughput of one every 4 s was possible with a precision of better than 1% relative standard deviation (n = 6) being observed for all standards and most samples. The results compared well with those from a standard manual titration.