Semiautomatic flow-injection method for the determination of volatile acidity in wines

摘要

A flow-injection (FI) method based on analytical pervaporation was assessed for its routine use in the determination of volatile acidity in winery laboratories. The new method was compared with both the official method and the Mathieu method, which is most often used in Spanish wineries, by testing 30 different wines, including young and aged, and sweet and dry wines from Montilla-Moriles appellation d´origine. The robustness of the new method was established and then all three methods were studied in terms of range of linearity and regression of the calibration curve, repeatability, reproducibility, sensitivity, detection and quantification limits (LOD and LQ, respectively) and time of analysis. The FI method surpasses the Mathieu method in reproducibility and both the Mathieu and official methods in LOD and LQ and sensitivity; it also requires less personnel involvement and shorter analysis time. The statistical criteria established by the “Office International de la Vigne et du Vin” were applied to the data and the results obtained indicated that the differences between the analytical parameters of the 3 methods are not significant and can be applied indistinctly. The correlation of the methods was studied by taking them 2 by 2, and the corresponding equations, coefficients and deviations confirmed the statistical results. Thus, the new method can be used in winery laboratories with clear advantages over its 2 counterparts (the routine and official methods).