METHODS FOR THE DETERMINATION OF THE CARBON-DIOXIDE EVOLVED FROM EFFERVESCENT SYSTEMS

Different methods for determining the carbon dioxide evolved from effervescent systems are described. In addition, a comparison between some of them is carried out when a stoechiometric mixture of L-tartaric acid and sodium bicarbonate reacts. The methods compared are: gravimetric, volumetric and gasometric. The gravimetric methods can be direct or indirect. The direct ones are based on taking in the carbon dioxide by a sorbent substance. The increase of weight after the absorption represents the CO2 evolved. In the indirect gravimetric methods the amount of carbon dioxide is determined by substraction of the weight of the sample after and before the effervescent reaction. The volumetric methods are based on an acid-base titration. In the method used, the carbon dioxide released reacts with barium hydroxide. The excess of barium hydroxide is titrated with oxalic acid. It is possible to calculate then the carbon dioxide produced in the reaction from the volume of oxalic acid used. In the gasometric methods the volume of gas is directly determined by the displacement of a solution when the gas is released. The gasometric method seems to be the most efficient among the studied ones.