Recovery of organic carbon from atmospheric particulate matter using soxhlet extraction with the benzene/methanol azeotrope∗

Research sponsored jointly by the U. S. Environmental Protection Agency under Interagency Agreement No. 40–1014–79, EPA No. AD‐89‐F‐2A073 and U. S. Department of Energy, under contract W‐7405‐eng‐26 with the Union Carbide Corporation.

Abstract

The extraction efficiency of the benzene/methanol azeotrope for organic carbon in atmospheric particulate matter was determined using a carbon types analyzer and also radio‐labeled tracers and liquid scintillation spectroscopy. A twenty‐four hour Soxhlet extraction with the azeotrope extracts 76 percent of the organic carbon, 15 percent of the elemental carbon, and 61 percent of the total carbon. Nonpolar and moderately polar organic compounds such as dotriacontane, benzo(a)pyrene, and stearic acid are extracted with 95 percent recovery. Highly polar oxygenated species such as succinic acid are extracted with an efficiency of 82 percent. The Soxhlet extractor was more efficient than ultrasonication for the extraction of highly polar species.

Key words:

• Soxhlet Extraction
• Benzene/Methanol Azeotrope
• Organic Carbon
• Extraction Recovery
• Radio‐Tracers
• Carbon Analysis
• Air Particulate Matter.

Notes

Research sponsored jointly by the U. S. Environmental Protection Agency under Interagency Agreement No. 40–1014–79, EPA No. AD‐89‐F‐2A073 and U. S. Department of Energy, under contract W‐7405‐eng‐26 with the Union Carbide Corporation.