新型激光光谱仪测定水样氢氧稳定同位素比率的分析方法与性能研究

Analytical method and performance research for determination of hydrogen and oxygen stable isotopes ratio in water sample by using new type of laser spectrum analyzer

为明确激光同位素光谱仪的性能特点、测试精度和减少记忆性误差,该文对基于波长扫描光腔衰荡光谱(WS-CRDS)技术的Picarro L1102i型激光同位素光谱仪进行快速分析方法和高精度分析方法的记忆性误差测试实验,并与MAT 253型同位素比质谱仪的测试结果进行精度对比,进而验证方法的可靠性。结果表明:高精度分析方法的数据精度优于快速分析方法,但两者并无本质差异;两种方法所得δ^(18)O测试值与MAT 253测试值的平均偏差都在0.000 1%以下,所得δD测试值与MAT 253测试值的平均偏差分别为0.001 6%和0.000 6%,均符合测试精度要求。基于Picarro L1102i型光谱仪的样品准备过程简单,测试成本比MAT 253型质谱仪低,在常规水样分析中具有较大的应用潜力。

In order to understand performance characteristics and test the accuracy of laser isotope spectrometer and reduce its memory error, memory error test have been carried out for rapid analysis method and high-precision analysis method of Picarro L1102 i laser isotope spectrometer which is based on the wavelength-scanned cavity ring down spectroscopy(WS-CRDS) technology,and the accuracy comparison was carried out with the test results of MAT 253 isotope ratio mass spectrometer so as to verify the reliability of the method. Results show that accuracy of data of high-precision analysis method is superior to rapid analysis method but there is no essential difference between them. The average deviation of δ^(18)O test value and MAT 253 test value obtained from these two methods is below 0.000 1% and the average deviation of δD test value and MAT 253 test value is respectively 0.001 6% and 0.000 6%, both of them meet precision test requirements. The preparation process of sample based on Picarro L1102 i spectrometer is simple and its test cost is lower than that of MAT 253 mass spectrometer, which is greatly potential in routine water sample analysis.