This method describes the quantitative analysis of associated natural gas for nitrogen, oxygen (if present), carbon dioxide, and hydrocarbons from C1 to C5 as individual components. C6, C7 and C8 hydrocarbons are measured as groups. It is intended to cover the following concentration ranges: Nitrogen 0.1-5.0; Carbon dioxide 0.1-5.0; Methane 0.4-20.0; Ethane 3.0-25.0; Propane 16.0-40.0; Isobutane 5.0-15.0; n-Butane 12.0-35.0; Isopentane 2.0-8.0; n-Pentane 2.0-8.0; Hexanes 0.1-2.0; Heptanes 0.1-1.0; Octanes <0-2; Oxygen <2.0.