Quantitative Gas-Liquid Chromatographic Determination of Ethyl Esters and Isoamyl Acetate in Whiskies and Rums and Confirmation by Mass Spectrometry

Abstract

Abstract A gas chromatographic method is described for determining isoamyl acetate and the ethyl esters caproate, caprylate, caprate, laurate, myristate, and palmitate in whiskies (Scotch and bourbons, light and Canadian) and rums (Caribbean and New England). A 4 0% ethanol solution saturated with salt was reduced to 5—10% ethanol by adding a saturated salt solution and extracting 3 times with pentane. For whiskies, the isoamyl acetate ranged from none detected (ND) to 4.5 ppm, ethyl caproate from ND to 3.9 ppm, ethyl caprylate from 0.9 to 16 ppm, ethyl caprate from 1.1 to 20.6 ppm, ethyl laurate from ND to 7.5 ppm, ethyl myristate from ND to 10.0 ppm, ethyl palmitate from ND to 8.0 ppm, and ethyl acetate from 69.4 to 717 ppm. The Caribbean rums showed the lowest concentration of ethyl esters and the New England rum showed the greatest concentration of these ethyl esters (C6 through C16). This method did not detect below 0.1 ppm. The identity of these esters was confirmed by gas-liquid chromatography- mass spectrometry.