ISO-CADICA: isotopic-continuous, automated dissolved inorganic carbon analyser.
ISO-CADICA: isotopic-continuous, automated dissolved inorganic carbon analyser.
复制标题
ISO-CADICA：同位素连续、自动溶解无机碳分析仪。
DOI：
10.1002/rcm.6143
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发表时间：
2012
期刊：
影响因子：
--
通讯作者：
C. Wurster
中科院分区：
文献类型：
--
作者：
A. Bass;M. Bird;N. Munksgaard;C. Wurster
理由
量化控制溶解无机碳（DIC）在水生系统中的动态过程是至关重要的生态系统碳预算的进展。开发一种方法，允许高分辨率的时间数据收集在较长的时间是必不可少的，并在本研究报告中描述。
方法
介绍了一种新型的采样仪器，该仪器依次酸化水的等分试样，并利用可透气ePTFE管，通过腔衰荡光谱法（CRDS）以亚小时间隔测量溶解无机碳（DIC）浓度和δ（13）C（DIC）值。
结果
同位素连续自动溶解无机碳分析仪（ISO-CADICA）系统的最低灵敏度为0.01 mM，准确度为0.008 mM。δ（13）C（DIC）值的分析不确定度与样品中DIC的浓度成正比。当DIC浓度大于0.3 mM时，分析不确定度为±0.1‰，低于0.2 mM时，稳定性< ± 0.3‰。气温、水温和CO（2）浓度的同位素效应可以忽略不计或可校正。现场试验测量珊瑚礁相关海水δ（13）C（DIC）值的昼夜变化，揭示了显着的，短期的时间变化，并说明了这种技术的必要性。
结论
目前，收集和分析大量样品用于δ（13）C（DIC）测量并不是微不足道的，但对于精确的碳模型，特别是小尺度的碳模型至关重要。ISO-CADICA可现场高分辨率测定DIC浓度和δ（13）C（DIC）值，无需样品储存和实验室分析。初步测试表明，该系统可以提供接近传统IRMS分析的精度。
RATIONALE
Quantifying the processes that control dissolved inorganic carbon (DIC) dynamics in aquatic systems is essential for progress in ecosystem carbon budgeting. The development of a methodology that allows high-resolution temporal data collection over prolonged periods is essential and is described in this study.
METHODS
A novel sampling instrument that sequentially acidifies aliquots of water and utilises gas-permeable ePTFE tubing to measure the dissolved inorganic carbon (DIC) concentration and δ(13)C(DIC) values at sub-hourly intervals by Cavity Ring-down spectrometry (CRDS) is described.
RESULTS
The minimum sensitivity of the isotopic, continuous, automated dissolved inorganic carbon analyser (ISO-CADICA) system is 0.01 mM with an accuracy of 0.008 mM. The analytical uncertainty in δ(13)C(DIC) values is proportional to the concentration of DIC in the sample. Where the DIC concentration is greater than 0.3 mM the analytical uncertainty is ±0.1‰ and below 0.2 mM stability is < ± 0.3‰. The isotopic effects of air temperature, water temperature and CO(2) concentrations were found to either be negligible or correctable. Field trials measuring diel variation in δ(13)C(DIC) values of coral reef associated sea water revealed significant, short-term temporal changes and illustrated the necessity of this technique.
CONCLUSIONS
Currently, collecting and analysing large numbers of samples for δ(13)C(DIC) measurements is not trivial, but essential for accurate carbon models, particularly on small scales. The ISO-CADICA enables on-site, high-resolution determination of DIC concentration and δ(13)C(DIC) values with no need for sample storage and laboratory analysis. The initial tests indicate that this system can offer accuracy approaching that of traditional IRMS analysis.