Larmor precession: observation and utilization for boosting the signal intensity of radio frequency glow discharge mass spectrometry

Wang, Mengli, Qian, Rong, Zhou, Shangjun, Chen, Qiao, Li, Zhongquan and Zhao, Bin (2020) Larmor precession: observation and utilization for boosting the signal intensity of radio frequency glow discharge mass spectrometry. Analytical Chemistry, 92 (14). pp. 9528-9535. ISSN 0003-2700

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A novel magnet array system was constructed to use Larmor precession for boosting the signal intensity of rf-GD-MS. The enhancement mechanism with four magnet array devices of single block magnet and 2×2, 3×2, and 3×4 magnet arrays was simulated and studied by COMSOL Multiphysics Software 5.4.0 (COMSOL) to determine if the electrons in the discharge plasma could perform Larmor precession along the direction perpendicular to the magnetic field. Induced by Larmor precession, inelastic collisions between the primary electrons and sample produced numerous secondary electrons and further improved the ionization efficiency. Moreover, the fuzzy synthetic evaluation result predicted that the device with 3×2 magnet array would display the greatest enhancement effect among the four devices. Based on these theoretical studies, a magnet array system with four magnet array devices was fabricated and utilized for studies of two scintillation crystals BGO and PWO. The observations indicated that the signal intensities obtained for 209Bi and 208Pb with the magnet array system were 630-3600 times of that obtained without magnet, and were enhanced by a factor of 1.5-2.8 compared with a previously reported stacked magnetic device. Two NIST samples were used to validate the method, and the results suggested that relative errors were less than 10% and the lowest detection limit for the 3×2 magnet array could reach 0.0032μg•g−1. Furthermore, the magnet array enhancement system with Larmor precession offers an efficient and sensitive approach for the direct analysis of non-conducting materials.

Item Type: Article
Keywords: Larmor precession, rf-GD-MS, magnet array, signal intensity, enhancement
Schools and Departments: School of Life Sciences > Chemistry
Subjects: Q Science > QD Chemistry > QD0071 Analytical chemistry
Depositing User: Qiao Chen
Date Deposited: 22 Jul 2020 07:08
Last Modified: 22 Jul 2020 07:15

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