Abstract: According to an example aspect of the present invention, there is provided a method of selectively catalytically reducing dinitrogen oxide present in a gaseous sample, comprising: providing a catalyst capable of reducing dinitrogen oxide; bringing the gaseous sample into contact with the catalyst to reduce dinitrogen oxide in the gaseous sample in the presence of the catalyst; wherein as a result of the reduction step, the gaseous sample is adapted for determination of the amount of an isotopic form of CO2 in the gaseous sample.

Abstract: According to an example aspect of the present invention, there is provided a method for preparing a gaseous isotope reference, the method comprising: providing a solid or liquid carbon-containing material exhibiting a carbon isotope ratio; providing oxygen gas or a gas mixture comprising oxygen gas, wherein said gas or gas mixture exhibits an oxygen isotope ratio; determining said carbon isotope ratio in the solid carbon-containing material and/or determining said oxygen isotope ratio in the oxygen gas or the gas mixture comprising oxygen; bringing the solid carbon-containing material in contact with the oxygen gas or the gas mixture comprising oxygen gas, in a high temperature in order to oxidize at least a part of the solid carbon-containing material to carbon dioxide to obtain the gaseous carbon and/or oxygen isotope reference in the form of carbon dioxide.

Abstract: According to an example aspect of the present invention, there is provided a method of detecting carbon dioxide in a gaseous sample, the method comprising: flowing the gaseous sample through an anion exchange resin that is capable of selectively adsorbing CO2 present in the gaseous sample; releasing the adsorbed CO2 from the resin by heating the resin to a temperature in the range 80 to 250° C. to obtain a concentrated gaseous sample; determining the amount of an isotopic form of CO2 in the concentrated gaseous sample by infrared absorption spectroscopy.

Abstract: A method of selectively catalytically oxidizing dinitrogen oxide present in a gaseous sample, comprising: heating a NiO catalyst to a temperature of at least 250° C.; and bringing the gaseous sample into contact with the heated NiO catalyst to oxidize dinitrogen oxide of the gaseous sample in the presence of the heated NiO catalyst.