Method 1: CaF2 Cell Beer’s Law The sample which has been diluted with cyclohexane is introduced into CaF2 (Figure 1) cell and the mid infraned absorption spectrum is recorded. The absorrbance of the typical absorption band for esters at about 1745 cm-1 is measured. The biodiesel content is then calculated with a calibration function produced […]

A sample is placed in a sample boat. The boat is then inserted into a high temperature combustion tube where the sulphur is oxidized to sulphur dioxide (SO2) in an oxygen-rich atmosphere. The sample combustion gases are next exposed to ultraviolet (UV) light. The SO2 absorbs the energy from the UV light and is converted […]

The sample is heated at 80C in a hermetically sealed vial to allow desorption of the contained methanol into the gas phase. When equilibrium is reached, a defined part of the gas phase is injected into a gas chromatograph (Figure 1), and methanol is detected with a flame ionization detecor. The amount of methanol is […]

A 300 ml sample of biodiesel is stored at 4.4C for 16 hr, amn dthen allowed to warn up to 20C-22C. The sample is then vacuum-filtered through a single 0.7 um glass fibre filter at a cotrolled vacuum pressure of 21 to 25 in. of Hg below atmospheric pressure (Figure 1). The time for the […]

PAHs are environmental and food-borne contaminants. Edible oils and fats may be contaminated by environmental pollutants and during the processing steps of crude oils prior to refining. The presence of PAHs in facts and oils is a health concern due to the carcinogenicity of the PAHs. Different levels of PAHs have been observed in crude […]