双聚焦扇型磁式高分辨ICP-MS在人体铁稳定同位素示踪研究中的应用

铁营养学研究是解决我国普遍存在的缺铁性贫血的关键环节 ,铁及其同位素比值测定方法是铁营养学研究的基础。人们传统地采用放射性同位素示踪法、中子活化法、热电离质谱法等作为铁营养学研究的辅助手段。该工作使用扇型磁式双聚焦高分辨ICP MS测定食品和粪便样品中铁同位素比值 ,用 30 0 0分辨率以避免40 Ar1 6O ,40 Ar1 4 N对56Fe ,54Fe的干扰 ,以快速多次电扫描方式降低等离子体波动的影响 ,以 5 μg·mL-1Fe标准溶液多次测定 ,统计计算得出54Fe/56Fe ,57Fe/56Fe和58Fe/56Fe等同位素比值测量精度分别为 0 2 3,0 1 4 ,0 2 2 % ,方法准确可靠、简便快速、已应用于铁营养学研究中。

Application of Double Focusing Magnetic Sector High Resolution ICP-MS to the Study of Iron Stable Isotope Trace

Iron absorption efficiency study is one of the key steps to overcome iron deficiency anemia. Determination of iron isotope ratios is the base of iron absorption study. For this purpose radioactive isotope trace method, neutron activation, and thermal ionization mass spectrometry etc. have been used as accessory means. A double focusing inductively coupled plasma mass spectrometry (DF-ICP-MS) was used to determine isotope ratios of Fe in food and human faeces in this paper. Interferences of 40Ar16O to 56Fe and 40Ar14N to 54Fe were avoided by using higher resolution (3000). Longer times and fast electronic scanning were employed to decrease the influence of signal fluctuations from the plasma. Instrumental parameters of the mass spectrometer were optimized while keeping the total integral time under 27s. RSD values obtained for isotope ratios of 5Fe/56Fe, 57Fe/56Fe and 58 Fe/56Fe were 0.23%, 0.14%, 0.22%, respectively, for a natural standard solution of 5 microg x mL(-1). The method has been used to iron nutrition studies.