应用于磷酸盐氧同位素测定的海水中溶解态磷酸盐的富集、分离与纯化

海水中溶解态磷酸盐的氧同位素组成(δ18Op)是海洋磷循环研究的有效示踪剂之一.海水中溶解态磷酸盐的富集、分离与纯化研究是测定海水磷酸盐氧同位素组成的基础.通过对国内外海水中磷酸盐氧同位素组成的测定方法进行查阅,选择改进后的MAGIC-CePO4沉淀-阳离子交换树脂法对海水中溶解态磷酸盐进行富集、分离与纯化,并对实验条件进行了探讨.实验结果表明,所采用的方法对于3种不同溶液体系3个步骤的磷酸盐平均回收率分别为92.8%,88.2%和98.3%,全流程磷酸盐回收率达到80%以上,因此可作为海水磷酸盐氧同位素测定的重要前提.

The Preconcentration,Separation and Purification of Phosphate for the Seawater Dissolved Phosphate Oxygen Isotope Composition Analysis

Dissolved phosphate oxygen isotope composition(δ~(18) O_p) was an effective tracer of ocean phosphate cycle.The preconcentration,separation and purification of phosphate was the foundation of seawater phosphate δ~(18) O analysis.Some popular seawater phosphate δ~(18) O analysis methods were reviewed.Then MAGIC-CePO_4 coprecipitation-cation exchange resin separation method was choosed to preconcentrate,separate and purify the phosphate.Some basic experiment conditions were also discussed.The results indicate that the mean phosphate recoveries of three procedures for three systems are 92.8%,88.2%,98.3%,and the total recovery of phosphate is more than 80%,so this method can be served as a basic precondition to determine the oxygen isotope composition of dissolved phosphate in seawater.