摘要
氢同位素核自旋异构体正-仲态比例影响氢同位素的低温物性,有必要对其比例进行测定。本文利用活性三氧化二铝多孔层开管(Porous Layer Open Tubular,PLOT)柱实现了正-仲氢同位素(氕、氘)的基线分离,发展了一种可在液氮温度下测定同核分子正-仲态比例的色谱分析技术。研究结果表明,与传统三氧化二铝填充柱相比,高效PLOT柱实现了正、仲氕(o-H_2、p-H_2)以及正、仲氘(o-D2、p-D2)的基线分离(分离度R_s大于1.5),当流量为5 m L·min-1时,分离度R_s(p-H_2,o-H_2)=6.9,R_s(o-D2,p-D2)=1.8。正仲态分离度与进样量、流量均有关系。根据峰面积的积分结果,常温(298 K)下正、仲氕比例为2.77:1,正、仲氘比例为1.78:1,与理论测算值基本符合。HD与o-H_2实现了部分分离,R_s(o-H_2,HD)=0.5,根据理论预测,实现HD与o-H_2的基线分离(R_s达到1.5),理论塔板数需要达到3.9×105。
Background： The cryogenic properties of hydrogen isotopes are affected by ortho-para ratio of the homonuclear molecules （H2, D2, T2）. Purpose： It is necessary to determine the ortho-para ratio. Methods： A cryogenic elution chromatographic method for determination of the ortho-para ratio is established, in which an activated alumina porous layer open tubular （PLOT） column with 30 m×0.53 mm×20 μm was applied for separation of the spin isomers. Results： The isomers were well separated at base line （the resolution Rs〉1.5） at temperature of liquid nitrogen （78 K）, compared with the conventional packed columns. When the Neon carrier rate is 5 mL.min-1, the resolution of ortho-para protium Rs （o-H2, p-H2） and ortho-para deuterium Rs （o-D2, p-D2） is 6.9, 1.8, respectively. Conclusion： The resolution is affected by sample content and flow rate. According to integration of peak areas, the ortho-para rate at 300 K for protium and deuterium is 2.77：1, 1.78：1, respectively, which is in accordance with the theoretical results. Partial separation is obtained between ortho-H2 and HD, and the resolution Rs （o-H2, HD） reached 0.4, theoretical plates of 3.9× 105 should be required to achieve the baseline separation （Rs=1.5）.
出处
《核技术》
CAS
CSCD
北大核心
2016年第11期55-60,共6页
Nuclear Techniques
基金
中国工程物理研究院院长基金(No.YZ2015009)资助~~
