The Natural Gas Analyser according to GPA 2261 is based on an Agilent 7890 GC with thermal conductivity detector, a special JAS valve solution and specially packed columns.

With the JAS NGA there are four columns connected in series with helium as carrier gas. First the hydrocarbons C6 and heavier are separated from the other components by a pre-column and then backflushed as a composite peak C6+. After being in "parking position" the three analytical columns are connected back in series step-by-step. The hydrocarbons C3 to C5 are detected next, followed by the permanent gases (O₂, N₂, CH₄, CO₂) and ethane.