This gas chromatographic method is for determining C8 and lower boiling paraffins and naphthenes in hydrocarbons containing less than 2 mass-% olefins (see Note 1) having a maximum final boiling point of 260°,C. Benzene and toluene are also determined. Certain non-aromatic components of interest are reported as composites and C8 aromatics are not determined (see Note 2). The quantitation limit for any reported component is 0.01 mass-%.