Isotope Dilution-AMS technique for 36Cl and Cl determination in low chlorine content waters
Isotope Dilution-AMS technique for 36Cl and Cl determination in low chlorine content waters
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DOI：
10.1016/j.chemgeo.2015.03.022
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发表时间：
2015-05-26
期刊：
影响因子：
3.9
通讯作者：
Bourles, Didier
中科院分区：
文献类型：
--
作者：
Bouchez, Camille;Pupier, Julie;Bourles, Didier
宇宙核素Cl-36由于其保守的氯化物形式而与水文应用有关。Cl-36的测量通常通过加速器质谱法（AMS）进行，而稳定氯浓度的测量通常通过离子色谱法（IC）进行。它们也可以通过同位素稀释-加速器质谱法（ID-AMS）来实现，该方法具有同时测定Cl和Cl-36含量的优点。该方法的适用范围已在岩石样品上进行了评估，但据我们所知，没有对氯化物含量低的水样进行实验测试。本研究旨在探讨ID-AMS方法对低氯水样品的准确性和精密度，因为氯和Cl-36的测定仍然具有很高的挑战性。首先，利用标准误差传播计算方法评估了测量比例的内部和外部误差，并评估了Cl和Cl-36浓度在+/- 5%和+/- 7%时的不确定度。在0.1 ~ 10 mg中心点L-1浓度范围内，用ID-AMS法测定了35个重量标准品的Cl浓度，得到了1:1线（R-2 = 0.99），对[Cl-]的1 σ不确定度为+/- 5%，与传播不确定度一致。最后，从理论上估计了在0.1 ~ 10 mg中心点L-1范围内的水样浓度时，用ID-AMS精确测量Cl-36和Cl的最佳样本量。(C) 2015 Elsevier B.V.版权所有
The cosmonuclide Cl-36 is relevant for hydrological applications due to its conservative chloride form. Cl-36 measurements are commonly performed by Accelerator Mass Spectrometry (AMS) while stable chlorine concentration measurements are usually performed by ion chromatography (IC). They can also be achieved by Isotope Dilution-Accelerator Mass Spectrometry (ID-AMS) which offers the advantage of the simultaneous determination of both Cl and Cl-36 contents. The range of applicability of this method has been assessed on rock samples but, to our knowledge, no experimental tests were conducted on water samples characterized by low chloride contents. This study aims at investigating the accuracy and precision of the ID-AMS method for such low chlorine water samples for which chloride and Cl-36 determinations remain highly challenging. First, internal and external errors were evaluated on the measured ratios and uncertainties on Cl and Cl-36 concentrations were assessed at +/- 5% and +/- 7% respectively using standard error propagation calculations. Focused on the 0.1 to 10 mg center dot L-1 concentration range, the Cl concentrations of thirty-five gravimetric standards were determined by ID-AMS leading to a 1:1 line (R-2 = 0.99) and a 1-sigma uncertainty on [Cl-] of +/- 5%, consistently with the propagated uncertainty. Finally, the optimal sample volume to reach accurate Cl-36 and Cl measurements with ID-AMS for water sample concentrations within the 0.1 to 10 mg center dot L-1 range has been theoretically estimated. (C) 2015 Elsevier B.V. All rights reserved.