Colorimetric Analysis of Fusel Oil in Rums Using o-Nitrobenzaldehyde as Color Reagent

Abstract

A new color reagent, o-nitrobenzaldehyde (ONB) was evaluated as a means of analysing the relatively high percentage of propyl alcohol in the fusel oil of Puerto Rican rums. The study comprised the establishment of the properties of the color developed by the products of the reaction, the effect of the proof of the solvent of the samples in the analysis and the relative sensitivity of the method for each of the alcohols that compose the fusel oil. The evaluation included the efficiency of other color reagents, salicylaldehyde (SA) and p-dimethylaminobenzaldehyde (PAB), in the analysis of total fusel oil content of a sample independent of its qualitative composition. The most adequate composition of the standard solution used as reference for the analysis is recommended. From the results obtained, a method is recommended, which compares satisfactorily with two other official colorimetric methods, because it is more simple and rapid. There was no acceptable correlation between the results of the ONB method and the gas chromatographic method, due principally to the low sensitivity of the colorimetric method for analysis of propyl alcohol. The method is, however, useful as an alternate for the colorimetric analysis of fusel oil in rums.