Determination of methanol in gasoline using liquid-liquid extraction and gas chromatography-flame ionisation detector (GC-FID)

Abstract

The concentration of methanol in gasoline was determined using liquid-liquid extraction and gas chromatographyflame ionisation detector (GC-FID). Methanol was transferred into the aqueous phase by liquid-liquid extraction before being separated on a Restek Rtx-Wax column and detected using a flame ionisation detector (FID). Gas chromatographic conditions, including column temperature programme, split ratio, and carrier gas flow rate, were investigated and selected to meet the requirement for methanol analysis. The methanol concentration in gasoline showed good linearity over the range of 3.96-7920 mg/l, with R²>0.99. The method detection limit (MDL) and method quantification limit (MQL) were 1.49 and 4.96 mg/l, respectively. The method precision, expressed as RSD, ranged from 1,49 to 4,96. The extraction recovery of methanol in gasoline ranged from 92.4 to 98.6%. The results indicated that the developed method meets accuracy requirements and is suitable for the determination of methanol in gasoline samples.