特定化合物碳同位素分析系统中的氧化反应装置的研制

摘要

A combustion reactor, the intermediate junction part between the gas chromatography(GC) and the isotope ratio mass spectrometry (IRMS), was developed by self-designing the major parts (including heating systems, temperature-control unit, the reaction systems and the connector). Between 600℃ and 950℃ , several working temperature was adopted to test the oxidizing efficiency of the newly-developed oxidation reactor by using the most representative chemically-stable hydrocarbon compounds (CH4, C2H6 and C3H8)) the results showed that the oxidation working temperature can be controlled with a high accuracy (± 1℃) and the carbon isotope ratio of hydrocarbons (δ13 C1, δ13 C2 and δ13 C3 ) gradually became stable with the reaction temperature increased, which conforms to the regular pattern of δ13Calkane analysis. Through the δ13Calkane analysis of hydrocarbon samples of different carbon number (l≤n ≤31), including the standard multi-components gaseous hydrocarbons, liquid hydrocarbon compounds (international reference standard) and the geological oil and gas samples, the δ13 Calkane accuracy is better than ± (0.2 - 0.5)%o> which can fully meet the related research needs. For the low-cost design and construction, this newly-developed oxidation reactor device can effectively reduce the analysis cost and it had made a good application in the δ13Calkane analysis.%通过对比实验,研制了特定化合物碳同位素在线分析系统中连接气相色谱与同位素比质谱的核心部分——氧化反应装置,包括加热系统、氧化反应系统及接口系统,并以特定化合物的碳同位素分析为例,选用天然气工作标准样品,在600～950℃之间选择8个温度点进行了氧化反应实验,表明其碳同位素测定值(δ13C1,δ13C2,δ13C3)随反应温度升高而逐渐趋于稳定,符合氧化反应过程的一般规律.通过对不同碳数(1≤n≤31)烃类样品(工作标准、国际参考标准、天然气及原油样品)的测试,显示碳同位素值(δ13Calkane)的测试精度优于±(0.2～0.5)‰,满足研究需求,并有效降低了分析成本,具有良好的应用及推广价值.