最近，中科院上海硅酸鹽研究所無機材料分析測試中心卓尚軍、錢榮等人的課題組與英國質(zhì)譜儀器公司（MSI）合作，將堆疊磁鐵系統(tǒng)和輝光放電質(zhì)譜儀（Autoconcept GD90-RF）的射頻源耦合，在非導(dǎo)體樣品中觀察到了超過50%的信號強度增益。作者借助ANSYS，對這種顯著信號增強現(xiàn)象的機理進行了分析，發(fā)現(xiàn)：振蕩磁場的引入，擴展了電子的運動路徑，增大了電子和中性粒子間的碰撞幾率，從而提高了非導(dǎo)體樣品的電離效率。同時，該現(xiàn)象在多種非導(dǎo)體樣品中得以再現(xiàn)，表明該方法是一種簡便、有效且具備一定普適性的方法。相關(guān)工作發(fā)表在國際權(quán)威學(xué)術(shù)期刊《Analytical Chemistry》上。

橫向堆疊磁鐵、橫向塊體磁鐵、軸向塊體磁鐵耦合和無磁鐵耦合情況下，Y2O3、BSO (Bi12SiO20)、BTN (Ba5.52La0.32Ti2Nb8O30)樣品中的Y、Bi、Ba的射頻放電信號對比。

用典型元素的信號強度表示的放電穩(wěn)定性：采用經(jīng)堆疊磁鐵耦合的射頻源，對(a)Y2O3、(b)BSO (Bi12SiO20)、(c)BTN (Ba5.52La0.32Ti2Nb8O30)樣品進行濺射得到的測量結(jié)果。

文章鏈接如下：

http://pubs.acs.org/doi/abs/10.1021/acs.analchem.6b04884

文章摘要如下：

A method for signal enhancement utilizing stacked magnets was introduced into high-resolution radio frequency glow discharge-mass spectrometry (rf-GD-MS) for significantly improved analysis of inorganic materials. Compared to the block magnet, the stacked magnets method was able to achieve 50–59% signal enhancement for typical elements in Y2O3, BSO, and BTN samples. The results indicated that signal was enhanced as the increase of discharge pressure from 1.3 to 8.0 mPa, the increase of rf-power from 10 to 50 W with a frequency of 13.56 MHz, the decrease of sample thickness, and the increase of number of stacked magnets. The possible mechanism for the signal enhancement was further probed using the software “Mechanical APDL (ANSYS) 14.0”. It was found that the distinct oscillated magnetic field distribution from the stacked magnets was responsible for signal enhancement, which could extend the movement trajectories of electrons and increase the collisions between the electrons and neutral particles to increase the ionization efficiency. Two NIST samples were used for the validation of the method, and the results suggested that relative errors were within 13% and detection limit for six transverse stacked magnets could reach as low as 0.0082 μg g–1. Additionally, the stability of the method was also studied. RSD within 15% of the elements in three nonconducting samples could be obtained during the sputtering process. Together, the results showed that the signal enhancement method with stacked magnets could offer great promises in providing a sensitive, stable, and facile solution for analyzing the nonconducting materials.