Neptune多接收器等离子体质谱精确测定锶同位素组成

报道了近两年来在Neptune多接收器等离子体质谱(MC-ICP-MS)上对NIST SRM987的测试结果。针对实际地质样品,Neptune MC-ICP-MS和热电离质谱(TIMS)进行了平行测定。Neptune MC-ICP-MS可以精确测定锶同位素组成,与传统的TIMS相比,MC-ICP-MS可以获得与TIMS相媲美的数据精度,而且分析时间短,效率高。对于等离子体载气———氩气中少量氪的干扰,可以直接扣除;对于样品中少量铷(Rb/Sr<0.01)的干扰,同样可以直接扣除,从而获得准确的锶同位素组成。

Accurate Measurement of Strontium Isotopic Composition by Neptune Multiple Collector Inductively Coupled Plasma Mass Spectrometry

This paper reported the analytical results of the NIST SRM987 measured by Neptune multiple collector inductively coupled plasma mass spectrometry(MC-ICP-MS) over last two years.Geological samples after traditional chemical separation were measured by Neptune MC-ICP-MS and thermal ionization mass spectrometry(TIMS),respectively.Neptune MC-ICP-MS can precisely measure strontium isotopic composition as the TIMS does,even more effective and less time-consuming than the TIMS method.For the krypton from ICP source carrier—the argon gas,isobaric interference can be directly corrected without the requirement for mass discrimination correction due to low level of the krypton ion beam.As for the sample containing small amount of rubidium(Rb/Sr<0.01),direct calibration for isobaric interference and mass discrimination by the exponential law can be obtained by assuming that rubidium mass discrimination is the same as that of strontium.