海水溶解有机质分离富集方法的发展与比较

Development and comparison of pretreatment methods for separation and enrichment of marine dissolved organic matter

溶解有机质(dissolved organic matter,DOM)在海洋生物地球化学循环中扮演着重要的角色。了解海洋DOM的化学组成和化学性质是理解海洋碳、氮等重要生源要素环境行为的必要前提。近年来快速发展的分析技术为解析DOM分子组成与结构提供了新的机遇,与多数陆地淡水DOM相比,海水DOM不仅具有浓度低、化学成分复杂的特征,而且伴随着很高的无机盐含量。光谱技术如紫外-可见光谱和三维荧光光谱可对过滤后的海水进行直接测定,但对质谱和核磁技术而言,只有对海水DOM进行分离和富集后才能满足高分辨率分析的要求。本文对常用的海水DOM分离富集方法,包括固相萃取(SPE)、反渗透电渗析(RO/ED)和超滤(UF)进行了综述,讨论了每种方法的优缺点,并对未来海水DOM的分析发展做了展望。

Dissolved organic matter(DOM)plays a key role in the marine biogeochemical cycle.Deciphering chemical composition and property of marine DOM is prerequisite to understand environmental behaviors of important biogenic elements(e.g.,carbon and nitrogen).Recent development and application of advanced analytical techniques open a new window for chemical characterization of DOM at the molecular level.Compared to freshwater DOM,marine DOM not only has extremely low carbon concentration and complex chemical composition,but also is associated with high inorganic salt concentration.Some spectral techniques,such as ultraviolet-visible and three-dimensional fluorescence spectra,can analyze seawater DOM after filtration;however,the separation and enrichment of seawater DOM are required for high resolution analysis by mass spectrometry and nuclear magnetic resonance.In this review,we summarize the commonly used separation/enrichment methods,including solid-phase extraction(SPE),reverse osmosis/Electrodialysis(RO/ED)and ultrafiltration(UF),discuss the advantage and limitation of each method,and provide a perspective on future research direction of marine DOM.