单体分子放射性碳同位素分析(CSRA)是近十几年来发展起来的一项新兴的分析手段,将所需的单体分子(生物标志物)从复杂的环境样品基质中分离并富集,再进行加速质谱仪(AMS)的放射性碳(HC)测定。这种分子水平的放射性碳同位素测定技术能够揭示出总有机质同位素组成的异质性,为解释有机碳的来源、迁移和转化等提供了新型的手段。在海洋科学研究中,单体分子放射性碳同位素分析已应用于计算碳在全球各储库的逗留时间并揭示和定量估算化石源有机碳的输入、指示沉积物的搬运过程、示踪微生物的代谢途径、改进沉积物年代学等;在环境科学研究中,单体分子放射性碳同位素分析可用于有毒物质(如多环芳烃)的源解析,示踪有机污染环境中微生物的代谢途径等。伴随着单体分子分离技术的改进及AMS灵敏度的提高,CSRA技术的应用会更加广泛。
Compound-specific radiocarbon analysis (CSRA) is a novel approach to isolate and recover sufficient quantities of individual target compounds (so-called biomarker) from complex organic matrices for Accelerator Mass Spectrometry (AMS) radiocarbon (14 C) analysis. This molecular level radiocarbon analysis can reveal the i- sotopic heterogeneity of total organic carbon, which provides a new approach to understand the carbon source, mi- gration and transformation. In oceanography, CSRA can provide direct information about the residence time of car- bon in global reservoirs and estimate the contribution of fossil carbon input to indicate sediment deposit processes in the past to understand the prokaryotic metabolic pathways and refine the sediment chronologies. In environ- mental science, CSRA can be used as a tool for source apportionment of toxic compounds (e. g. , PAHs) and for the determination of microbial carbon sources in petroleum contaminated sediments. As the individual compound separation technology and AMS sensitivity both improve, CSRA technology will be more widely applied in the fu- ture.