ASTM 3612/TOGA/DissolvedGasGC
RevisedOctober 2013
TheSRI ASTM 3612/TOGA/
DissolvedGasGC configuration
( TOGAGC ) permitsmeasurement
of gasses dissolved inwater, oil or
other liquids, and is based on the re-
quirements of ASTMmethod 3612,
optionC, which specifies the use of
headspace to extract the gasmole-
cules from the liquid.
A headspace vial like the 40ml vial
shown above is half filled ( 20ml ) with
liquid and then thegas above the liq-
uid is purgedwith inert gas like argon,
nitrogen or helium. Gases ( CH4,
CO, CO2 etc ) which are dissolved in
the liquid then escape into the inert
headspacewhere they accumulate
until an equilibrium is reached.
Those gases are then injected into
theGC.
