元素分析-同位素比质谱法与液相色谱-同位素比质谱法测定乙醇中δ13C值

Determination of δ13C in ethanol by elemental analyzer-isotope ratio mass spectrometry and liquid chromatography-isotope ratio mass spectrometry

中文关键词:  乙醇  碳同位素  元素分析-稳定同位素比质谱法  液相色谱-稳定同位素比质谱法

英文关键词:ethanol  carbon isotope, elemental analyzer-isotope ratio mass spectrometry  liquid chromatography- isotope ratio mass spectrometry

中文摘要:

      目的 研制木薯乙醇和玉米乙醇中碳同位素标准物质, 探讨碳同位素准确定值技术。方法 定值分别采用元素分析-稳定同位素比质谱法(elemental analyzer-isotope ratio mass spectrometry, EA-IRMS)和液相色谱-稳定同位素比质谱法(liquid chromatography-isotope ratio mass spectrometry, LC-IRMS)。LC-IRMS分析过程中, 将标准物质BCR657分别与待测样品和标准物质BCR660混合, 可以实现对乙醇和蔗糖δ13C值的同时测定。结果 LC-IRMS方法验证结果显示使用该方法检测的标准物质BCR660的测量值在标准值的不确定度范围内, 证明了混合检测方法的可行性。使用En值核查法对2种检测方法检测得到的乙醇样品δ13C值进行检验, |Encassava|=0.952, |Enmaize|=0.551, En值均小于1, 证明2种检测方法所测结果等效一致。结论 该方法不但有利于对乙醇进行多方法定值, 且弥补了气相色谱-稳定同位素比质谱法(gas chromatography-isotope ratio mass spectrometry, GC-IRMS)标准物质有限的缺陷。本研究建立的分析技术和研制的标准物质可用于食品真实性鉴别。

英文摘要:

      Objective To develop the carbon isotope reference materials in cassava ethanol and maize ethanol, and explore the accurate certification technology for carbon isotope. Methods Certification was conducted by the combination of elemental analyzer-isotope ratio mass spectrometry (EA-IRMS) and liquid chromatography-isotope ratio mass spectrometry (LC-IRMS). In LC-IRMS, CRM BCR657 was mixed with the sample and CRM BCR660, respectively, which could perform simultaneous determination of δ13C in both ethanol and sucrose. Results The determined results in BCR660 were within the uncertainty range, which verified the feasibility of simultaneous determination of ethanol and sugar by LC-IRMS. The δ13C values of ethanol samples determined with EA-IRMS and LC-IRMS were inspected with En method, which showed that |Encassava|=0.952, |Enmaize|=0.551, respectively. Both values were less than 1, which implied that the methods agreed with each other well. Conclusion These methods are not only beneficial to the determination of ethanol by multi-methods, but also make up for the limited defect of GC-IRMS (gas chromatography-isotope ratio mass spectrometry) by supplying reference materials. Based on the techniques, new carbon isotope reference materials are developed for GC-IRMS, further, this technique and reference materials will helpful for food authenticity.