An open system pyrolysis of a first hydrocarbon source rock sample obtained from a natural system is performed within a pyrolysis chamber by maintaining the pyrolysis chamber at a substantially constant temperature. Hydrocarbons are recovered from the pyrolysis chamber released by the first hydrocarbon source rock sample. A thermo-vaporization is performed within the pyrolysis chamber on the pyrolyzed sample at a substantially constant temperature. A first hydrocarbon expulsion efficiency of hydrocarbon source rock is determined. A second hydrocarbon rock sample is ground to a grain size less than or equal to or less than 250 micrometers. A second pyrolysis is performed on the ground hydrocarbon source rock sample by maintaining the chamber at a substantially constant temperature. A second hydrocarbon expulsion efficiency of the hydrocarbon source rock in the natural system is determined. The first hydrocarbon expulsion efficiency is verified using the second hydrocarbon expulsion efficiency.

The disclosed system and method improve measurement of trace volatile chemicals, such as by Gas Chromatography (GC) and Gas Chromatography/Mass Spectrometry (GCMS). A first trapping system can include a plurality of capillary columns in series and a focusing column fluidly coupled to a first detector. The first trapping system can retain and separate compounds in a sample, including C3 hydrocarbons and compounds heavier than C3 hydrocarbons (e.g., up to C12 hydrocarbons, or compounds having a boiling point around 250 C.), and can transfer the compounds from the focusing column to the first detector. A second trapping system can receive compounds that the first trapping system does not retain, and can include a packed trap and two columns. The second trapping system can remove water from the sample and can separate and detect compounds including C2 hydrocarbons and Formaldehyde.

The present techniques, including methods and systems, relate to obtaining or producing a concentrated gas sample from a non-concentrated gas sample with a trap that is not inline with (or indirectly connected to) a chromatographic method, and injecting a controlled volume of the concentrated gas sample in a sample loop including a valve or similar chromatographic component through a sample line. The method includes preparing the concentrated gas sample from the non-concentrated gas sample with a trap; controlling a temperature of an internal volume of the trap to reach a release temperature; injecting the concentrated gas sample in a sample line towards a sample loop, the sample line and sample loop being at a sub-atmospheric pressure; and operating the sample loop to release the concentrated gas sample contained in the sample loop in a chromatographic method, wherein the trap is not inline with the chromatographic method.

A water removal method for gas concentration sampling, and a sampling method and device. The water removal method comprises: removing water from a sample gas by means of a first cold trap tube filled with a hydrophilic material, and then concentrating the sample gas by means of a concentration cold trap tube; then by means of a carrier gas, conveying components desorbed by the first cold trap tube under a heating state to a second cold trap tube that is in a cooled state and that is filled with a hydrophobic organic adsorbent material, and adsorbing organic substances in the components desorbed by the first cold trap tube: by means of the carrier gas, bringing the moisture desorbed by the first cold trap tube out of the second cold trap tube, and then by means of the carrier gas, conveying residual components desorbed by the first cold trap tube and the second cold trap tube under the heating state to the concentration cold trap tube for concentration.

A thermal desorption tube collection system uses a thermoelectric cooler to collect and concentrate gas samples. In some modes, the operation of the cooler is reversed to flow the concentrated sample directly into a separator such as a gas chromatography system. Components resolved in time by a thermal desorption separator accumulate in a sample cell and are analyzed by electromagnetic radiation-based spectroscopic techniques. Also presented are methods for analyzing biogas samples.

An open system pyrolysis of a first hydrocarbon source rock sample obtained from a natural system is performed within a pyrolysis chamber by maintaining the pyrolysis chamber at a substantially constant temperature. Hydrocarbons are recovered from the pyrolysis chamber released by the first hydrocarbon source rock sample. A thermo-vaporization is performed within the pyrolysis chamber on the pyrolyzed sample at a substantially constant temperature. A first hydrocarbon expulsion efficiency of hydrocarbon source rock is determined. A second hydrocarbon rock sample is ground to a grain size less than or equal to or less than 250 micrometers. A second pyrolysis is performed on the ground hydrocarbon source rock sample by maintaining the chamber at a substantially constant temperature. A second hydrocarbon expulsion efficiency of the hydrocarbon source rock in the natural system is determined. The first hydrocarbon expulsion efficiency is verified using the second hydrocarbon expulsion efficiency.

A primary trap concentrates the sample, followed by forward flushing of retained compounds more volatile than CO.sub.2 to a secondary trap. In some embodiments, prior to CO.sub.2 elution, the primary trap is isolated from the secondary trap and pressure in the primary trap is reduced to sub-atmospheric. At this time, a pressure sensor measures expansion of CO.sub.2 into a vacuum reservoir to determine the amount of CO.sub.2 and CO.sub.2 is removed. Optionally, inert gas is used to eliminate any remaining CO.sub.2, either at positive pressure instead of removing CO.sub.2 under vacuum, or as an optional additional step after removing CO.sub.2 under vacuum. After the CO.sub.2 is removed, the primary trap is heated and backflushed to the secondary trap, which is then preheated and either injected directly to a GCMS, or further condensed using an open tubular focusing trap for even faster injection rates into the GCMS.