Characterization of Soluble Organic Fraction in DPM: Optimization of the Extraction Method 1999-01-3532
Different extraction techniques have been analyzed when applied to the extraction of the soluble organic fraction from diesel particulate matter (DPM). It has been proved that a complete extraction (not frequently reached under conditions usually adopted in literature) is needed if a good characterization of both soluble and insoluble organic fraction is to be attained.
Ultrasonication and microwave methods with mixtures of dichloromethane and benzene used as solvent lead to maximum extraction efficiency under two different conditions. Supercritical extraction with CO2 was also performed during 20 minutes in static state and 20 minutes in dynamic state, with similar results to these techniques. However, soxhlet extraction reaches higher efficiency, but only if the number of cycles and the solvent composition are carefully chosen. An incomplete extraction leads to misinterpretation of the SOF origin, since the oil contribution is not satisfactory considered. After this study, a soxhlet extraction with dichloromethane/benzene (70/30) during 400 cycles is recommended in order to obtain comparable results.