Ultra-precise stable Fe isotope measurements by high resolution multiple-collector inductively coupled plasma mass spectrometry with a 57Fe-58Fe double spike
Ultra-precise stable Fe isotope measurements by high resolution multiple-collector inductively coupled plasma mass spectrometry with a 57Fe-58Fe double spike
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DOI：
10.1016/j.chemgeo.2012.01.021
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发表时间：
2012-04
期刊：
影响因子：
3.9
通讯作者：
M. Millet;J. Baker;C. E. Payne
中科院分区：
文献类型：
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作者：
M. Millet;J. Baker;C. E. Payne
我们开发了一种多收集器电感耦合等离子体质谱法（MC-ICP-MS）高精度测量稳定铁同位素的方法，利用57fe - 58fe双尖峰校正仪器质量偏差。利用脱溶雾化器和对54fe +、56Fe+和57fe +的典型质量分辨率分别为3300、3100和2700的伪高分辨率质谱，最大限度地减少了40ar14n +、40Ar16O+和40ar16o1h +对Fe同位素的多原子干扰。用双尖刺IRMM-014铁同位素标准的样品标准包套解释了铁离子峰下这些干扰的残余尾巴。一系列分析测试表明，在一次15分钟的分析中，可以获得±0.02至0.04‰的内部精度（2 se）。通过重复（n=51）对IRMM-14进行为期6个月的分析，获得了±0.02‰的长期重现性（2 sd）。玄武岩标准BHVO-2 （δ56Fe=+0.128±0.019‰）的重复消化和分析表明，这种外部再现性在天然样品上也可获得。利用这一新技术，我们获得了一系列国际标准物质（BHVO-2、BCR-2、JB2、bir1、AGV-2、JA1、GSP-1、JG3a、JR1、RGM-1和JF2）的高精度稳定铁同位素数据。该范围的火成岩标准岩（玄武岩、安山岩、花岗闪长岩、流纹岩）的数据与先前发表的高精度样品标准套法得到的值吻合良好，并强调bir1是目前最好的校准标准岩，参考δ56Fe值为+0.052±0.009‰（95% c.i）。给出了BHVO-2、BCR-2、JB2、BIR-1、AGV-2的其他参考值。来自伟晶岩的JF2碱长石的稳定铁同位素数据明显重（δ56Fe=+0.816±0.025‰），可能是由于结晶过程中同位素重的岩浆Fe3+掺入长石矿物结构所致。
We have developed a method for high precision measurement of stable Fe isotopes by multiple-collector inductively coupled plasma mass spectrometry (MC-ICP-MS), utilizing a57Fe–58Fe double spike to correct for instrumental mass bias. Polyatomic interferences of40Ar14N+,40Ar16O+and40Ar16O1H+on Fe isotopes are minimized by the use of a desolvating nebulizer and pseudo-high resolution mass spectrometry with typical mass resolutions of 3300, 3100 and 2700 on54Fe+,56Fe+and57Fe+, respectively. Sample-standard bracketing with double spiked IRMM-014 Fe isotope standards accounts for residual tails from these interferences beneath the Fe ion peaks. A range of analytical tests demonstrates that it is possible to attain internal precisions (2 se) of ±0.02 to 0.04‰ on a single 15min analysis. Long-term reproducibility (2 sd) of ±0.02‰ was obtained by replicate (n=51) analyses of IRMM-14 over a 6-month period. Replicate digestions and analyses of the basalt standard BHVO-2 (δ56Fe=+0.128±0.019‰) demonstrate that this external reproducibility is also obtainable on natural samples. Utilizing this new technique, we present high precision stable Fe isotope data for a range of international reference materials (BHVO-2, BCR-2, JB2, BIR-1, AGV-2, JA1, GSP-1, JG3a, JR1, RGM-1 and JF2). Data for this range of igneous standards (basalt, andesite, granodiorite, rhyolite) are in good agreement with previously published values obtained by high precision sample-standard bracketing techniques, and highlight that BIR-1 is the best calibrated standard available with a reference δ56Fe value of +0.052±0.009‰ (95% c.i.). Other reference values for BHVO-2, BCR-2, JB2, BIR-1, AGV-2 are also presented. Stable Fe isotope data for the JF2 alkali feldspar from a pegmatite are markedly heavy (δ56Fe=+0.816±0.025‰), perhaps due to the incorporation of isotopically heavy magmatic Fe3+into the feldspar mineral structure during crystallization.