Detailed assessment of isotope ratio infrared spectroscopy and isotope ratio mass spectrometry for the stable isotope analysis of plant and soil waters.
Detailed assessment of isotope ratio infrared spectroscopy and isotope ratio mass spectrometry for the stable isotope analysis of plant and soil waters.
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DOI：
10.1002/rcm.5204
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发表时间：
2011-10
期刊：
影响因子：
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通讯作者：
L. Zhao;Honglang Xiao;Jian Zhou;Lixin Wang;G. Cheng;Maoxian Zhou;L. Yin;M. Mccabe
中科院分区：
文献类型：
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作者：
L. Zhao;Honglang Xiao;Jian Zhou;Lixin Wang;G. Cheng;Maoxian Zhou;L. Yin;M. Mccabe
作为同位素比质谱法（IRMS）的替代方法，同位素比红外光谱法（IRIS）具有低成本、连续测量和现场应用能力的优点，用于分析水的稳定同位素。最近的研究表明，IRIS方法中光谱信号存在潜在的有机污染问题，导致叶子样本的结果不正确。为了更全面地了解样品类型的影响（例如，本文利用IRIS技术，在黑河流域3个不同气候条件的地点，以高分辨率（24-48 h，每2 h一次）采集了主要植物的土壤样品和植物组分，并对不同气候条件下的土壤样品和植物组分进行了分析。使用IRMS和IRIS仪器测量从这些样品中提取的水的氢和氧同位素组成。结果表明，IRMS法和IRIS法测定的δ（18）O和δD的平均差值分别为：叶水-5.6‰和-75.7‰，茎水-4.0‰和-23.3‰，根水-3.4‰和-28.2‰，木质部水-0.5‰和-6.7‰，木质部流量-0.06‰和-0.3‰，茎水-23.3 ‰和-23.3 ‰。土壤水为-0.1‰和0.3‰。各处理间的差异大小顺序为：叶>茎>根>木质部>木质部流>土壤。一般来说，相同功能类型的物种（例如，木本与草本）在相似的生境中表现出类似的差异。对于不同的功能类型，差异较大。夜间采样未消除观察到的偏差。
As an alternative to isotope ratio mass spectrometry (IRMS), the isotope ratio infrared spectroscopy (IRIS) approach has the advantage of low cost, continuous measurement and the capacity for field-based application for the analysis of the stable isotopes of water. Recent studies have indicated that there are potential issues of organic contamination of the spectral signal in the IRIS method, resulting in incorrect results for leaf samples. To gain a more thorough understanding of the effects of sample type (e.g., leaf, root, stem and soil), sample species, sampling time and climatic condition (dry vs. wet) on water isotope estimates using IRIS, we collected soil samples and plant components from a number of major species at a fine temporal resolution (every 2 h for 24-48 h) across three locations with different climatic conditions in the Heihe River Basin, China. The hydrogen and oxygen isotopic compositions of the extracted water from these samples were measured using both an IRMS and an IRIS instrument. The results show that the mean discrepancies between the IRMS and IRIS approaches for δ(18) O and δD, respectively, were: -5.6‰ and -75.7‰ for leaf water; -4.0‰ and -23.3‰ for stem water; -3.4‰ and -28.2‰ for root water; -0.5‰ and -6.7‰ for xylem water; -0.06‰ and -0.3‰ for xylem flow; and -0.1‰ and 0.3‰ for soil water. The order of the discrepancy was: leaf > stem ≈ root > xylem > xylem flow ≈ soil. In general, species of the same functional types (e.g., woody vs. herbaceous) within similar habitats showed similar deviations. For different functional types, the differences were large. Sampling at nighttime did not remove the observed deviations.