Accurate measurement of light hydrocarbons is very effective for gas, condensate, and most oil exploration, as well as minerals and geothermal. DIRECT GEOCHEMICAL routinely measures C₁-C₆ (and sometimes higher as needed), including ethene and propene, plus iso-butane, pentanes, and hexanes, using GC/FID. Low ppb concentrations can be acquired by thermally desorbing soils, from free or soil gas samples, or from VaporTec^TM passive soil gas samplers.