A novel laser ablation cell geometry significantly reduces the so-called position effect on high precision and accuracy isotopic measurements by Laser Ablation-Multiple Collector-Inductively Coupled Plasma-Mass Spectrometry (LA-MC-ICP-MS). The peak shape, amplitude and pulse duration of the ⁵⁶Fe signal for a single laser shot at the carrier gas flow rate in a range from 0.85 to 1.4 L min⁻¹ were studied, and then twelve analytical areas in the sample cell were selected to assess the homogeneity of aerosol transport efficiency in response to a single laser shot under optimized gas flow conditions. To further investigate whether position effects occur in the new cell, the Fe isotopic composition of Balmat pyrite was measured with extreme separation distances between the ‘sample’ and ‘standard’ in horizontal and vertical carrier gas flow directions in two gas flow rate scenarios. The results show that the position effect on Fe isotopic ratios is obvious at a flow rate of 0.85 L min⁻¹. Nevertheless, the position effect is negligible at a flow rate of 1.00 L min⁻¹. The Fe isotopic composition of in-house reference pyrite sample H1 is determined with δ⁵⁶Fe and δ⁵⁷Fe values of −0.11 ± 0.20 (2SD, n = 24) and −0.19 ± 0.40 (2SD, n = 24), respectively. These results are consistent with those measured by MC-ICP-MS solution methods (95% confidence interval). We conclude that the new sample cell can be extensively applied for high precision and accuracy LA-MC-ICP-MS stable isotope analysis.

中文翻译：

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用于减少激光烧蚀MC-ICP-MS同位素测量中的“位置效应”的新型样品池†

新颖的激光烧蚀池几何形状通过激光烧蚀-多收集器-电感耦合等离子体质谱法（LA-MC-ICP-MS）显着降低了对高精度和高精度同位素测量的所谓位置效应。研究了载气流速在0.85至1.4 L min ^-1范围内的单次激光发射的⁵⁶ Fe信号的峰形，幅度和脉冲持续时间，然后选择了样品池中的十二个分析区域评估在优化的气流条件下对单个激光照射的气溶胶传输效率的均匀性。进一步调查位置效应是否如果发生在新电池中，则在两种气体流速情况下，在水平和垂直载气流动方向上，在“样品”和“标准”之间的极远分离距离下，对Balmat黄铁矿的Fe同位素组成进行了测量。结果表明，在流速为0.85 L min ^-1时，位置对Fe同位素比的影响是明显的。然而，在1.00 L min ^-1的流速下，位置效应可忽略不计。内部参考黄铁矿样品H1中的Fe同位素组成与确定的δ ⁵⁶ Fe和δ ^57个-0.11±0.20的值的Fe（2SD，Ñ = 24）和-0.19±0.40（2SD，Ñ= 24）。这些结果与通过MC-ICP-MS溶液方法测得的结果一致（95％置信区间）。我们得出的结论是，新的样品池可广泛用于高精度和高精度的LA-MC-ICP-MS稳定同位素分析。