Development of Combustion Reactor Furnace Applied to Compound Specific of Carbon Isotope Ratio Analysis

A combustion reactor furnace applied to compound specific of carbon isotope ratio analysis, which was also the intermediate junction part between the gas chromatography (GC) and the isotope ratio mass spectrometry (IRMS), were developed by self-designing the major parts that mainly consist of heating systems, temperature control unit, reaction systems and connector and etc. Between 600 °C and 950 °C, by using the most representative chemically stable hydrocarbon compounds, such as CH4, C2H6 and C3H8, several working temperature points were adopted to test the oxidizing efficiency of the newly developed furnace. The results showed that the oxidation working temperature could be controlled with high accuracy (±1 °C) and the carbon isotope ratio of hydrocarbons (δ13C1, δ13C2 and δ13C3) gradually became lighter, and then tend to be stable with the increasing reaction temperature, which conforms to the regular pattern of δ13Calkane analysis. By using the combustion reactor furnace, the problem of variation in the isotopic values for incomplete oxidization was also ideally resolved. Through the δ13Calkane analysis of hydrocarbon samples with different carbon numbers (1 ≤ n ≤31), including the standard natural gas samples, the crude oil samples and the international reference standard, the δ13Calkane accuracy is better than ±(0.2–0.5)‰, which can fully meet the research needs. The newly-developed combustion reactor device with low-cost construction can effectively reduce the analysis cost, and can be used for the δ13Calkane analysis.