Suspended matter in jet fuel was separated by filtration and analyzed using scanning electron microscopy, energy-dispersive X-ray spectrometry, X-ray diffractometry, infrared spectrophotometry and gas chromatograph-mass spectrometry. The results showed that the components in the suspended matter include alkanes, esters with long molecular chains and multi-substituents, alcohols, ketones, alkenes and heteroatomic compounds containing nitrogen and sulfur. This work will assist in the ultimate determination of the chemical composition of the suspended matter and an understanding of its mode of formation. (c) 2005 Elsevier Ltd. All rights reserved.