Citation: WU Shi-Tou, HUANG Chao, XIE Lie-Wen, YANG Yue-Heng, YANG Jin-Hui. Iolite Based Bulk Normalization as 100% m/m Quantification Strategy for Reduction of Laser Ablation-Inductively Coupled Plasma Mass Spectrometry Transient Signal. Chinese Journal of Analytical Chemistry, 2018, 46(10): 1628-1636. doi: 10.11895/j.issn.0253-3820.181291 [复制]
Iolite Based Bulk Normalization as 100% m/m Quantification Strategy for Reduction of Laser Ablation-Inductively Coupled Plasma Mass Spectrometry Transient Signal
Iolite软件具有数据处理能力强、可视化效果好和计算代码开源等优点，近年来受到国内外LA-ICP-MS实验室广泛关注。本研究探究了Iolite软件处理LA-ICP-MS元素含量信号时的应用情况，并撰写了基体归一化100%（m/m）计算代码。采用Iolite软件对仪器信号漂移校正时，发现平滑插值要优于线性插值。采用基体归一化100%（m/m）代码校准得到的BCR-2G结果显示，绝大多数元素与推荐值匹配，表明此代码是可行和可靠的。不同的外标校准物质所得的结果有差别，NIST SRM 610作外标校准物质时，BCR-2G的TiO2、MgO、K2O和稀土元素分析结果有5%~10%偏差。StHs6/80-G作外标校准物质时，Cr和Mo分析结果偏高10%~30%，这可能与基体效应或校准物质推荐值不确定度有关。合成不确定度的3个主要来源分别为校准物质测定元素推荐值不确定度、样品元素信号比值和基体归一化误差。基于Iolite软件和基体归一化100%（m/m）代码，定量校准了CGSG-1、CGSG-2、CGSG-4、CGSG-5中的50种元素，主量元素（除Mn、Ca和P外）与推荐值的偏差在5%以内，微量元素（除Cr、Ni、Zn、Ga、Mo和Sb外）与推荐值的偏差小于10%，这些数据可为CGSG标准物质实验室联合定值提供数据支撑。所撰写的基体归一化代码拓宽了Iolite软件在处理LA-ICP-MS信号时的应用范围。
As the advantages of powerful data-handling capacity, excellent signal visualization and open source of calculation codes, Iolite package draw more attention in laser ablation-inductively coupled plasma mass spectrometry (LA-ICP-MS) community in recent years. In this study, the application of Iolite package was investigated for LA-ICP-MS elemental quantification, and a quantification code for bulk normalized as 100% (m/m) strategy was compiled. We found that the spline interpolation was better than linear interpolation for the correction of time-dependent instrument drift. BCR-2G as monitor material was used to evaluate the proposed code and the results revealed that the code was practical and reliable. The analytical results are affected by the used calibration materials. TiO2, MgO, K2O and rare earth elements in BCR-2G were slightly off (5%-10%) when NIST SRM 610 as the calibrator, while Cr and Mo were higher (10%-30%) than the recommended values when StHs6/80-G as the calibrator. Those phenomenon were attributed to the matrix effect or the inaccurate values of corresponding calibrators. Three main sources for the LA-ICP-MS combined uncertainty were recognized, which included the uncertainty of recommended values of analytes in calibration material, the uncertainty of measured intensity ratios in samples and the error in bulk normalized as 100% (m/m) strategy. 50 elements in CGSG glass reference materials were quantified based on the proposed Iolite code. Major elements (except MnO, CaO and P2O5) matched with the preliminary values in 5% and trace elements (except Cr, Ni, Zn, Ga, Mo and Sb) were agreement with the preliminary values in 10%. The dataset reported in this study was useful for the certification of CGSG reference materials. Overall, the proposed Iolite code broadened the application of Iolite package in the reduction of LA-ICP-MS transient signal.
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