This method is for determining the distribution of paraffins andnaphthenes by carbon number, in hydrocarbon samples having anendpoint of 200°C or less (C3-C11). C12 at concentrations less than3 can be determined. Olefins and aromatics interfere and must beremoved prior to analysis by ASTM Method D 2002, D 2003 or othersuitable technique. The lower limit of detection for a singlecarbon number hydrocarbon type is 0.05 mass- or LV-.