魔角旋转固体核磁共振探头中转子的研制

Design and Fabrication of a Magic-Angle Spinning Rotor for Solid-State Nuclear Magnetic Resonance Probe

转子作为魔角旋转(MAS)探头一个至关重要的部件,是固体样品高速旋转的载体,被广泛应用于各种固体核磁共振(NMR)实验.但国内关于MAS转子的研究极少,以至其长期被国外市场垄断.本文通过对MAS转子的深入研究,设计了常规的4 mm MAS转子;并对MAS转子进行了流固耦合仿真,分析其应力应变大小;同时进行了模态仿真,确定了MAS转子的各阶振型及临界转速;最后制作了转子,进行了转速测试和固体NMR实验.结果表明,本文设计和制作的转子能在14 kHz转速下正常运行,并在4 kHz及12.5 kHz转速下采集了金刚烷标样的1H NMR信号,结果表明该转子能满足常规固体NMR实验的需求.

Magic-angle spinning(MAS)rotor,a device for high-speed spinning of solid samples,is an essential component of the probes used in solid-state nuclear magnetic resonance(NMR)experiments.In this study,a 4 mm MAS rotor was designed and fabricated in-house.Fluid-solid coupling simulation was carried out to compute the stress and strain in the MAS rotor.Modal analysis was performed to determine the various modes and critical speeds of the MAS rotor.Actual spinning speed test and MAS NMR sampling were carried out to test the performance of the rotor.The results showed that the MAS rotor built in-house could operate normally at a spinning speed up to 14 kHz.The 1H NMR signals of adamantane collected at 4 kHz and 12.5 kHz were collected and compared.These results demonstrated that the 4 mm MAS rotor built in-house could meet the requirements of conventional solid-state NMR experiments.