Rapid monitoring of transesterification and assessing biodiesel fuel quality by near‐infrared spectroscopy using a fiber‐optic probe

Vegetable oil esters, particularly methyl esters, are being explored and used as alternative diesel fuel (biodiesel). The transesterification reaction which yields the methyl esters can be monitored for completion by near‐infrared (NIR) spectroscopy using a fiber‐optic probe. Although the NIR method is less sensitive than gas chromatography (GC) for quantifying minor components, by correlation with existing GC or other analytical data, biodiesel fuel quality can be assessed through the NIR method. The NIR method is easier and faster to use than GC.