论文信息 - pH-metric determination of acid values in vegetable oils without titration

pH-metric determination of acid values in vegetable oils without titration

A new method for determining acid values in vegetable oils has been developed for a nontitration pH-metric technique with a reagent consisting of 0.20 M triethanolamine in a 1∶1 solution of water and isopropanol. The emulsive properties of this reagent provide rapid (within a minute) and quantitative extraction of free fatty acids from an oil into the solvent phase. Acid values were determined by measuring conditional pH of the emulsified reagent in a pH-meter with an aqueous reference electrode. Three different applications of this technique are discussed.

[1] J. Sedman,et al. Rapid quantitative determination of free fatty acids in fats and oils by fourier transform infrared spectroscopy , 1993 .

[2] M. Valcárcel,et al. Determination of Free Fatty Acids in Dairy Products by Direct Coupling of a Continuous Preconcentration Ion-Exchange-Derivatization Module to a Gas Chromatograph , 1994 .

[3] T. Venkatesan,et al. Aqueous isopropyl alcohol for extraction of free fatty acids from oils , 1989 .

[4] I. Kuselman,et al. Alternative methods for titratable acidity determination. , 1995, Talanta.

[5] D. Firestone,et al. Official methods and recommended practices of the American Oil Chemists' Society , 1990 .

[6] G. Johansson,et al. Dynamic response of the glass electrode , 1968 .

[7] Miguel Valcárcel,et al. Automatic method for on-line preparation of fatty acid methyl esters from olive oil and other types of oil prior to their gas chromatographic determination , 1993 .