A methodology to determine additive markers in fuel ethanol using gas chromatography-mass spectrometry

Abstract

Ethanol has been increasingly utilized on a large scale as a biofuel. In Brazil, hydrated fuel ethanol is available in two types: regular (EHC) and a version known as additive ethanol (EHA), which contains multifunctional chemical compounds for enhanced performance. Each brand or distributor may select various additive packages for additive options. The detection of additives in fuels, such as gasoline and diesel, is widely discussed in scientific literature; however, methodologies capable of assessing the presence of these additives and correlating them with their origin are lacking. Thus, this study developed a new methodology to distinguish between EHA and EHC, and to identify fuel additives characteristic of the major brands available in the Brazilian market, using gas chromatography coupled with mass spectrometry (GC–MS) and a multivariate analysis-based approach. Overall, 198 commercial fuel ethanol samples were analyzed, 98 EHC and 99 EHA. A regression model built using 17 chemical compounds presented an accuracy of 97 %. Oleic acid, 2-ethylhexanol, and 1,4-diethylbenzene were identified as the main chemical markers. In summary, this study presents a rapid, robust, and highly accurate method for distinguishing between additive and regular hydrated fuel ethanol, representing a breakthrough in biofuel quality assurance. This advancement contributes significantly to ensuring the quality of biofuels, with direct impacts on environmental safety, preventing economic losses, and strengthening oversight and regulation in the sector.