植物中硼分离方法的建立及其同位素质谱测定

Separation and Analysis of Boron and Its Isotopic Composition in Plants

硼是植物生长所必须的一种微量营养元素，在植物体生殖器官的建成和发育过程中起着关键作用。本实验将干灰化法与两步离子交换色谱法结合，建立了植物中硼的分离富集方法。本方法能够消除大量有机质，硼的回收率达到约100％，能满足硼同位素正热电离质谱法测试的需求。测定结果表明，两种植物中硼的同位素组成变化范围为-19．45‰-5．73‰，平均值为-2．80‰，在植物体不同组织之间存在着非常明显的硼同位素分馏。两种植物的茎中相对富集^10B，造成^11B相对贫乏，而在花和叶中相对富集^11B。为进一步利用同位素技术研究植物生长过程硼的行为和全球硼的循环提供了可能。

A method was developed to extract and concentrate boron in the plants （Echinacea Purpurea and Weigela Florida CV. Red Prince） by dry ashing coupled with two-step ion exchange chromatography. Boron isotope was subsequently analyzed by positive thermal ionization mass spectrometry. By the method, the effect of organic impurities on the determination can be eliminated and the boron can be recovered completely. The results showed the composition of boron isotope in the two plants ranged from -19.45%o to ＋5.73%o with the average of -2. 80%o, which indicated that a significant fractionation of boron isotope composition in the different tissues of the plants occurs,^11B was enriched in stems in the two plants, which resulted in defect of ^11B, but ^11B was enriched in flower and leaf relatively. This may be resulted in not only by the transpiration, but the biological effects of boron acid being bound to hydroxyl-rich organic molecules like sugars in the growth of plant, which puts forward a new method for the further investigation of boron behavior within plants and soil, and the global cycling of boron in the biogeochemistry.