This method is for determining the carbon structure of C9 andlower boiling hydrocarbons in cyclic-free, liquid olefinic samples.The endpoint of these samples should not exceed 216 C. Completehydrogenation of olefins to paraffins is accomplished directlywithin the chromatographic injection system enabling a carbonstructure determination to be made. Components in the C10 to C12range that may be present in the sample are not individuallyidentified, and are reported as a summation. The lower limit ofdetection for any single hydrogenated component is 0.05 mass-%.