This method is primarily for determining total non-aromatic hydrocarbons below the one mass-% level in individual or mixed aromatic hydrocarbon samples. For the purpose of this method, total non-aromatics is defined as the composite of those components eluting before benzene. The applicability is limited to samples containing compounds having a maximum of 11 carbon atoms. The method may also be used to determine mass-ppm concentrations of benzene in specific sample types containing predominantly C₇ and higher boiling aromatics, or benzene and toluene in specific sample types containing predominantly C₈ and/or higher boiling aromatics. The method is quantitative to one mass-ppm.