Using compounds modified by the isotopes carbon-13 and nitrogen-15 helps conduct research in various fields of science, such as medicine, pharmacology, pharmacokinetics, metabolism, agriculture, and others. In the cas...Using compounds modified by the isotopes carbon-13 and nitrogen-15 helps conduct research in various fields of science, such as medicine, pharmacology, pharmacokinetics, metabolism, agriculture, and others. In the case of the availability of reliable, express, and cheap methods, the area of their use will gradually expand. A determination of the atomic fraction of the isotopes carbon-13 and nitrogen-15 directly in glycine, leucine, isoleucine, and alanine is proposed;the modification concerns all centers or one or more identical carbon and nitrogen centers separately, as well as both isotopes at the same time. There are defined mass lines of the mass spectrum of each amino acid, through which the isotopic content of carbon and nitrogen is calculated. The processes that must be taken into account for the determination of the isotopic content are also established. Isotopic analysis of these compounds until now was carried out by transforming them into carbon oxide, dioxide, and molecular nitrogen, and determination of their content in individual centers was impossible.展开更多
市场上橄榄油掺假现象屡禁不止,传统鉴定方法存在局限性。本研究利用元素分析仪-稳定同位素比质谱仪(elemental analyzer-isotope ratio mass spectrometer,EA-IRMS)对市场上常见的7种植物油进行氢、碳稳定同位素比值检验,并对测量结果...市场上橄榄油掺假现象屡禁不止,传统鉴定方法存在局限性。本研究利用元素分析仪-稳定同位素比质谱仪(elemental analyzer-isotope ratio mass spectrometer,EA-IRMS)对市场上常见的7种植物油进行氢、碳稳定同位素比值检验,并对测量结果进行显著性差异分析,同时分析橄榄油中氢、碳稳定同位素比值的相关性。结果表明:橄榄油中δD范围为-146.78‰~-125.30‰,δ^(13)C范围为-29.72‰~-28.59‰,与其他品类植物油中氢稳定同位素比值差异显著(P<0.05),与除葵花籽油、野山茶油外的植物油中碳稳定同位素比值差异显著(P<0.05);且橄榄油中氢、碳稳定同位素比值具有较强的相关性(Pearson’s r=0.904)。计算模拟豆油、玉米油对橄榄油掺假的情况,结果表明,氢、碳稳定同位素比结合分析最低能检测出玉米油掺假10%、豆油掺假30%以上的情况。该研究可为橄榄油的掺假鉴定提供方法参考。展开更多
文摘Using compounds modified by the isotopes carbon-13 and nitrogen-15 helps conduct research in various fields of science, such as medicine, pharmacology, pharmacokinetics, metabolism, agriculture, and others. In the case of the availability of reliable, express, and cheap methods, the area of their use will gradually expand. A determination of the atomic fraction of the isotopes carbon-13 and nitrogen-15 directly in glycine, leucine, isoleucine, and alanine is proposed;the modification concerns all centers or one or more identical carbon and nitrogen centers separately, as well as both isotopes at the same time. There are defined mass lines of the mass spectrum of each amino acid, through which the isotopic content of carbon and nitrogen is calculated. The processes that must be taken into account for the determination of the isotopic content are also established. Isotopic analysis of these compounds until now was carried out by transforming them into carbon oxide, dioxide, and molecular nitrogen, and determination of their content in individual centers was impossible.
文摘市场上橄榄油掺假现象屡禁不止,传统鉴定方法存在局限性。本研究利用元素分析仪-稳定同位素比质谱仪(elemental analyzer-isotope ratio mass spectrometer,EA-IRMS)对市场上常见的7种植物油进行氢、碳稳定同位素比值检验,并对测量结果进行显著性差异分析,同时分析橄榄油中氢、碳稳定同位素比值的相关性。结果表明:橄榄油中δD范围为-146.78‰~-125.30‰,δ^(13)C范围为-29.72‰~-28.59‰,与其他品类植物油中氢稳定同位素比值差异显著(P<0.05),与除葵花籽油、野山茶油外的植物油中碳稳定同位素比值差异显著(P<0.05);且橄榄油中氢、碳稳定同位素比值具有较强的相关性(Pearson’s r=0.904)。计算模拟豆油、玉米油对橄榄油掺假的情况,结果表明,氢、碳稳定同位素比结合分析最低能检测出玉米油掺假10%、豆油掺假30%以上的情况。该研究可为橄榄油的掺假鉴定提供方法参考。
