Hendrickson C L, Drader J J, Laude D A, Guan S, Marshall A G
Center for Interdisciplinary Magnetic Resonance, National High Magnetic Field Laboratory, Florida State University, Tallahassee 32310, USA.
Rapid Commun Mass Spectrom. 1996;10(14):1829-32. doi: 10.1002/(SICI)1097-0231(199611)10:14<1829::AID-RCM697>3.0.CO;2-U.
We present Fourier transform ion cyclotron resonance (FTICR) mass spectra at a magnetic field of 20 T; more than twice the highest field previously used for FTICR. Our instrument is based on a resistive magnet installed at the National High Magnetic Field Laboratory. The magnet has a 50 mm diameter bore and spatial inhomogeneity of approximately 1000 ppm over a 1 cm diameter spherical volume. However, FTICR mass resolving power far in excess of magnet homogeneity is achieved routinely for ions produced by either electron ionization (EI) or matrix-assisted laser desorption/ionization (MALDI). As examples, we show a MALDI mass spectrum of [M + H] quasimolecular ions of the peptide, human luteinizing hormone-releasing hormone (monoisotopic molecular weight, 1181.6 Da) at mass resolving power, m/delta m > 10,000; and an EI mass spectrum of molecular ions of the platinum cluster compound, Pt4(PF3)8 (average molecular weight, 1484 Da at mass resolving power, m/delta m approximately 20,000. Much better FTICR MS performance is predicted for future NHMFL resistive magnets of higher spatial and temporal homogeneity.
我们展示了在20 T磁场下的傅里叶变换离子回旋共振（FTICR）质谱；该磁场强度是此前用于FTICR的最高磁场强度的两倍多。我们的仪器基于安装在美国国家强磁场实验室的一个电阻磁体。该磁体的孔径为50 mm，在直径1 cm的球形体积内空间不均匀性约为1000 ppm。然而，对于通过电子电离（EI）或基质辅助激光解吸/电离（MALDI）产生的离子，通常能够实现远超磁体均匀性的FTICR质量分辨能力。例如，我们展示了肽类人促黄体生成素释放激素（单同位素分子量为1181.6 Da）的[M + H]准分子离子的MALDI质谱，其质量分辨能力m/Δm > 10,000；以及铂簇化合物Pt4(PF3)8的分子离子的EI质谱，其平均分子量为1484 Da，质量分辨能力m/Δm约为20,000。预计未来具有更高空间和时间均匀性的美国国家强磁场实验室电阻磁体将实现更好的FTICR质谱性能。
