Gas Chromatography-Mass Spectrometry (GC-MS) profiling of fatty acid methyl esters produced from groundnut-coconut oil biodiesel blends

The increasing demand for sustainable energy and the environmental challenges associated with fossil fuel consumption have intensified the search for renewable alternatives such as biodiesel. The quality of biodiesel is largely influenced by the feedstock used during production, making the blending of vegetable oils an effective strategy for improving fuel properties. This study investigated the production and characterization of biodiesel derived from blended groundnut (Arachis hypogaea) and coconut (Cocos nucifera) oils using potassium hydroxide (KOH) as a homogeneous catalyst.ah Three feedstock blend ratios (80:20, 70:30, and 60:40 groundnut oil: coconut oil) were transesterified with methanol at 50–60 °C. The produced biodiesel samples were characterized using Gas Chromatography–Mass Spectrometry (GC–MS) to determine their fatty acid methyl ester (FAME) composition, while Fourier Transform Infrared Spectroscopy (FTIR) was used to confirm ester formation. Physicochemical properties, including biodiesel yield, density, kinematic viscosity, acid value, moisture content, and flash point, were evaluated in accordance with ASTM D6751 and EN 14214 standards. GC–MS analysis identified methyl laurate, methyl myristate, methyl palmitate, methyl oleate, methyl linoleate, and methyl stearate as the major fatty acid methyl esters. The blend ratios influenced the proportions of saturated and unsaturated esters, resulting in variations in fuel properties. FTIR spectra confirmed successful transesterification through characteristic ester carbonyl (C=O) and C–O absorption bands. The measured physicochemical properties were generally within the acceptable limits specified by ASTM D6751 and EN 14214, demonstrating good fuel quality. The study concludes that blending groundnut and coconut oils provides a viable approach to producing high-quality biodiesel and supports the utilization of locally available vegetable oils for sustainable biofuel production, energy diversification, and reduced dependence on fossil fuels.