Gravimetric Determination of Carbon Dioxide in Wines

Abstract

A gravimetric determination of CO2 in wines was both accurate and relatively fast when compared with the titrimetric method. When 21 samples of lightly carbonated wine were analyzed by both methods the average results agreed within 0.2 mg (range of agreement from 0.1 to 5.0 mg CO2/100 ml wine). In the gravimetric procedure, the CO2 contained in the wines is converted into the carbonate by adding 50% NaOH to the previously chilled sample. An aliquot is introduced into a closed vacuum system. The CO2 is evolved by adding HCl and shaking and warming the reaction flask. The generated gases are pulled through the system by a vacuum pump. Along the path, the gases are dried and purified, and finally the CO2 is absorbed by Indicarb reagent between layers of anhydrous magnesium perchlorate. The absorption bulb is weighed before and after absorption of CO2.