Monitoring of Fatty Acid Derivatives and Vegetable Oils by the Quartz Crystal Microbalance

This study investigated the characterization of fatty acid derivatives and vegetable oils by the quartz crystal microbalance (QCM). Resonant frequency and resistance were monitored for fatty acid derivatives and vegetable oils by a QCM sensor at 35℃ and 55℃. The resonant resistance depended on varieties of fatty acid derivatives, although the resonant frequency was similar for them. Oleic acid showed higher resonant resistance than methyl and ethyl oleate and oleyl alcohol. The resonant resistance of fatty acid methyl esters showed lower value according to the unsaturation (numbers of double bonds). Glyceryl oleate showed remarkably higher resonant resistance than oleic acid and its esters. Triolein showed the highest resonant resistance among glyceryl oleate. The resonant resistances of vegetable oils also depended on their varieties and iodine value (IV). Olive oil with the lowest IV showed the highest resonant resistance, while linseed oil with the highest IV showed the lowest resonant resistance among tested vegetable oils. The resonant resistances of vegetable oils reduced with their IV. These results suggested QCM may be effective for identification of vegetable oils.