International Atomic Energy Agency, Isotope Hydrology Section, Division of Physical and Chemical Sciences, Vienna International Centre, P.O. Box 100, 1400 Vienna, Austria.
Rapid Commun Mass Spectrom. 2012 Aug 15;26(15):1641-8. doi: 10.1002/rcm.6270.
The interpretation of stable hydrogen and oxygen isotope data in isotope hydrology relies on accurate, high-precision analytical measurements of the (2)H:(1)H and (18)O:(16)O ratios in liquid H(2)O samples.
A synthesis of the International Atomic Energy Agency (IAEA) worldwide proficiency test for analytical laboratories conducting routine analysis of δ(2)H and δ(18)O values in water (WICO2011) by isotope-ratio mass spectrometry (IRMS) and laser absorption spectroscopy (LAS) technology has been carried out.
This test revealed that >96% of the 160 laboratory submissions provided acceptable results within ±2‰ for δ(2) H values and ±0.2‰ for δ(18)O values of the established reference values for four test waters, and no difference in outcomes based on IRMS vs. LAS technology was found for good performing laboratories.
The leading cause of outliers appeared to be improper calibration or compromised storage of laboratory standard and primary reference waters; hence the importance of judicious storage of lab standards cannot be understated. The deprecated practice of single standard normalization was identified as a problem for some laboratories. We further recommend that laboratories strive to report parsimonious long-term precisions based upon control standards, and to improve quantification and correction for LAS instrumental drift and inter-sample carryover effects.
同位素水文学中稳定氢和氧同位素数据的解释依赖于液体 H2O 样品中 (2)H:(1)H 和 (18)O:(16)O 比值的准确、高精度分析测量。
对国际原子能机构（IAEA）进行的全球分析实验室能力验证测试（WICO2011）进行了综合分析，该测试采用同位素比质谱（IRMS）和激光吸收光谱（LAS）技术对水的 δ(2)H 和 δ(18)O 值进行常规分析。
该测试表明，在四个测试水中，160 个实验室提交的结果中，有超过 96%的结果在 δ(2)H 值为 ±2‰，δ(18)O 值为 ±0.2‰范围内，符合既定参考值，并且对于表现良好的实验室，IRMS 与 LAS 技术的结果没有差异。
异常值的主要原因似乎是实验室标准和主要参考水的校准不当或储存不当；因此，明智储存实验室标准的重要性不容忽视。一些实验室被发现采用单一标准归一化的过时做法是一个问题。我们进一步建议实验室努力根据控制标准报告简明的长期精密度，并提高 LAS 仪器漂移和样品间夹带效应的定量和校正。
