Constraining the abundance and distribution of halogens in geological materials has the potential to provide novel insights into a broad range of earth system processes (e.g. metasomatism, melting, volatile cycling and ore formation). In this contribution we develop analytical protocols for the in situ measurement of Cl, Br and I in widely distributed standard reference materials (apatite, scapolite, silicate glass) using readily available laser ablation ICP-MS instrumentation. Ablations were performed at a range of square spot sizes (30–80 μm) using a high repetition rate (25 Hz) and extended analyte dwell times (up to 250 ms) to improve sensitivity and signal stability. A comparison of LA-ICP-MS results with published halogen data was used to calculate the following theoretical limits of quantification; Cl = 360 μg/g, Br = 8 μg/g, I = 0.75 μg/g. A detailed assessment of raw signal intensities for different matrices with known halogen contents, combined with high resolution mass scans, provides new constraints on the origin of apparent halogen signals: on mass Cl signal excesses are likely OOH and/or OO; Br is influenced by peak shoulder overlap from ArAr (a diargon cation, Ar) and a matrix-based interference (Tb) for samples with Br/Tb < 0.6; I signals are similar for all but the highest I materials analysed here, suggesting the presence of ubiquitous gas-based interferences. The observation that false positive halogen signals only occur during sample ablation suggests that they are either matrix derived or related to the process of sample introduction. During ablation, matrix loading may reduce plasma energy, resulting in a greater proportion of polyatomic interferences in the system. For Cl, we provide a new time dependent excess apparent Cl spline correction defined by analysis of halogen-free olivine via a modified version of the Iolite Data Reduction Scheme ‘X_Trace_Elements_IS’. The correction improves the limit of linearity to ~100 μg/g for Cl in glasses down to a 38 μm spot size. We test our methodology on apatite from Permian alkaline lamprophyres in the Pyrenees (Spain) and quartz-hosted melt inclusions from rhyolitic deposits at the Taupo volcanic zone (New Zealand), obtaining results comparable to electron microprobe and SIMS data. We provide recommendations for analytical best practice and highlight the need for well characterised matrix matched SRMs spanning a broad range of concentrations to allow for the identification and removal of non-analyte related contributions to measured signals.

中文翻译：

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LA-ICP-MS 微量分析磷灰石、方柱石和硅酸盐玻璃中的 Cl、Br 和 I

限制地质材料中卤素的丰度和分布有可能为广泛的地球系统过程（例如交代作用、熔融、挥发性循环和矿石形成）提供新的见解。在这一贡献中，我们开发了使用现成的激光烧蚀 ICP-MS 仪器对广泛分布的标准参考材料（磷灰石、方长石、硅酸盐玻璃）中的 Cl、Br 和 I 进行原位测量的分析协议。使用高重复率 (25 Hz) 和延长的分析物驻留时间（高达 250 ms）在一系列方形光斑尺寸 (30–80 μm) 下进行消融，以提高灵敏度和信号稳定性。LA-ICP-MS 结果与公布的卤素数据的比较用于计算以下定量的理论极限：Cl = 360 μg/g，Br = 8 μg/g，I = 0.75 μg/g。对具有已知卤素含量的不同基质的原始信号强度的详细评估，结合高分辨率质量扫描，为表观卤素信号的来源提供了新的限制：质量 Cl 信号过量可能是 OOH 和/或 OO；对于 Br/Tb < 0.6 的样品，Br 受 ArAr（一种双氩离子，Ar）的峰肩重叠和基于基质的干扰 (Tb) 的影响；除了此处分析的最高 I 材料之外，所有 I 信号都相似，表明存在普遍存在的基于气体的干扰。观察到假阳性卤素信号仅在样品消融过程中出现，表明它们要么是基质衍生的，要么与样品引入过程有关。在消融过程中，基质加载可能会降低等离子体能量，从而导致系统中更大比例的多原子干扰。对于 Cl，我们提供了一种新的时间相关的过量表观 Cl 样条校正，通过对无卤橄榄石的分析定义，通过 Iolite 数据缩减方案“X_Trace_Elements_IS”的修改版本。对于玻璃中的 Cl 至 38 μm 光斑尺寸，校正将线性限制提高到 ~100 μg/g。我们对来自比利牛斯山脉（西班牙）的二叠纪碱性萤石的磷灰石和来自陶波火山区（新西兰）的流纹岩沉积物的石英熔体包裹体进行了测试，获得了与电子微探针和 SIMS 数据相当的结果。我们为分析最佳实践提供建议，并强调需要跨越广泛浓度的良好表征的基质匹配 SRM，以允许识别和去除对测量信号的非分析物相关贡献。我们提供了一个新的时间相关的过量表观 Cl 样条校正，通过对无卤橄榄石的分析定义，通过 Iolite 数据减少方案“X_Trace_Elements_IS”的修改版本。对于玻璃中的 Cl 至 38 μm 光斑尺寸，校正将线性限制提高到 ~100 μg/g。我们对来自比利牛斯山脉（西班牙）的二叠纪碱性萤石的磷灰石和来自陶波火山区（新西兰）的流纹岩沉积物的石英熔体包裹体进行了测试，获得了与电子微探针和 SIMS 数据相当的结果。我们为分析最佳实践提供建议，并强调需要跨越广泛浓度的良好表征的基质匹配 SRM，以允许识别和去除对测量信号的非分析物相关贡献。我们提供了一个新的时间相关的过量表观 Cl 样条校正，通过对无卤橄榄石的分析定义，通过 Iolite 数据减少方案“X_Trace_Elements_IS”的修改版本。对于玻璃中的 Cl 至 38 μm 光斑尺寸，校正将线性限制提高到 ~100 μg/g。我们对来自比利牛斯山脉（西班牙）的二叠纪碱性萤石的磷灰石和来自陶波火山区（新西兰）的流纹岩沉积物的石英熔体包裹体进行了测试，获得了与电子微探针和 SIMS 数据相当的结果。我们为分析最佳实践提供建议，并强调需要跨越广泛浓度的良好表征的基质匹配 SRM，以允许识别和去除对测量信号的非分析物相关贡献。