Optimizing LA-ICP-MS analytical procedures for elemental depth profiling of foraminifera shells
Optimizing LA-ICP-MS analytical procedures for elemental depth profiling of foraminifera shells
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DOI：
10.1016/j.chemgeo.2015.04.007
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发表时间：
2015-06-22
期刊：
影响因子：
3.9
通讯作者：
Eggins, Stephen
中科院分区：
文献类型：
--
作者：
Fehrenbacher, Jennifer S.;Spero, Howard J.;Eggins, Stephen
激光烧蚀电感耦合等离子体质谱（LA-ICP-MS）是一种广泛应用于有孔虫方解石元素比值分析的技术。在这里，我们专注于优化LA-ICP-MS通过壳壁的元素比的高分辨率深度剖析。该应用程序揭示了壳内变异性，并提供了一个独特的机会，以量化微量元素掺入在短时间尺度的钙化由一个单独的有孔虫。高分辨率深度分析需要仔细考虑消融和分析条件，以解决亚微米壳厚度上壳化学的差异。我们提出了NIST SRM 610标准玻璃数据（cps）和元素/Ca比的激光烧蚀轮廓（以mmol/mol为单位）从有孔虫方解石中分离出，所述有孔虫方解石是使用Photon Machines 193 nm UV准分子激光烧蚀系统在一系列操作条件下获得的，所述系统配备有双体积ANU HelEx室，与Agilent 7700 x四极ICP-MS耦合。并且质谱仪循环时间可以产生变化的元素分布。这种变异性可以模拟和/或掩盖有孔虫壳中真实的壳内微量元素异质性。在低（= 3 Hz）激光重复率和/或信号平滑装置下，提高了壳内微量元素分布的准确度和精度。当使用5 Hz或更高的重复频率和3 J/cm（2）或更高的能量密度时，髋臼杯材料被快速消融，导致空间分辨率降低。(C)2015 Elsevier B. V.版权所有。
Laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS) is becoming a widespread technique for analyzing elemental ratios in foraminiferal calcite. Here we focus on optimizing LA-ICP-MS for high-resolution depth profiling of elemental ratios through shell walls. This application reveals intrashell variability and provides a unique opportunity to quantify trace element incorporation over short time scales of calcification by an individual foraminifer. High-resolution depth profiling requires careful consideration of both ablation and analytical conditions required to resolve differences in shell chemistry across sub-micron shell thickness. We present laser ablation profiles of NIST SRM 610 standard glass data (in cps) and elemental/Ca ratios (in mmol/mol) from foraminiferal calcite obtained over a range of operating conditions using a Photon Machines 193 nm UV excimer laser-ablation system, equipped with a dual-volume ANU HelEx chamber, coupled to an Agilent 7700x quadrupole ICP-MS. Different combinations of energy density, repetition rate, and mass spectrometer cycle time can yield varying elemental profiles. This variability can mimic and/or mask real intrashell trace element heterogeneity in foraminifer shells. At low (= 3 Hz) laser repetition rates and/or a signal-smoothing device improves the accuracy and precision of intrashell trace element profiles. Shell material is ablated rapidly when using a 5 Hz or greater repetition rate and an energy density of 3 J/cm(2) or greater, resulting in reduced spatial resolution. (C) 2015 Elsevier B.V. All rights reserved.