is a composition analysis test (ASTM-D-2007), for determining weight percent of asphaltenes, saturated hydrocarbons, aromatics, and polar compounds in a petroleum product. The method is a liquid chromatographic technique (see chromatography). The test material is mixed with pentane, asphaltenes are extracted as pentane insolubles, and the remainder of the sample is washed through a column. Active clay at the top of the column separates or absorbs polar compounds, silica gel at the bottom separates aromatics, and saturates (naphthenes and paraffins) pass through with the pentane.