PHASE-MODULATED STORED WAVE-FORM INVERSE FOURIER-TRANSFORM EXCITATION FOR TRAPPED ION MASS-SPECTROMETRY
PHASE-MODULATED STORED WAVE-FORM INVERSE FOURIER-TRANSFORM EXCITATION FOR TRAPPED ION MASS-SPECTROMETRY
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DOI：
10.1021/ac00130a016
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发表时间：
1987-02-01
影响因子：
7.4
通讯作者：
MARSHALL, AG
中科院分区：
文献类型：
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作者：
CHEN, L;WANG, TCL;MARSHALL, AG
存储波形傅里叶逆变换（SWIFT）技术提供了用于在傅里叶变换离子回旋共振（FT/ICR）或离子阱质谱中激发和/或喷射具有任何质荷比范围的离子的通用方法。在本文中，我们表明，任何几种类型的非线性相位调制（最好是，二次相位调制）的原始频域频谱逆傅里叶变换之前，可以成功地产生所需的低动态范围在时域以及最佳平坦的频域发射机功率。时域波形的Apodlzatlon进一步平滑最终的激励功率分布。相位调制的SWIFT激发比目前可用的扫频激发更上级，用于增强质量分辨率。在质谱/质谱实验中，通过多离子喷射丰度离子来增强动态范围和质量分辨率，更均匀的激发幅度用于改进同位素比测量，多离子同时监测，以及同时喷射/喷射组合。傅里叶变换离子回旋共振（FT-ICR）质谱（1，2）已经发展成为一种非常通用的质谱技术，它提供高质量分辨率，同时检测整个质谱，并且还没有达到质量上限（见参考文献3-10中的评论）。FTICR中目前可用的激励方法如图1所示。单频激发（图1的顶部迹线）是用于产生第一个FT-ICR光谱的方法（1），也是FT-NMR中的主要激发方法。然而，如图1右上角所示，该频域激励频谱的“正弦”幅度曲线仅在小频率范围（约±（0.1/T）Hz，其中T是时域脉冲的持续时间）内是平坦的（在几个百分比内）。一般来说，单脉冲激发在整个化学质量范围内产生几乎平坦的功率（即，带宽约为1000 nm）。3 MHz，3 T）将需要非常短的时域脉冲（约0.1 us）的不切实际的大幅度（> 104 V，对于1英寸板分离）（11）。
The stored waveform inverse Fourier transform (SWIFT) technique offers a general method for exciting and/or ejecting Ions having any range (s) of mass-to-charge ratios In either Fourier transform ion cyclotron resonance(FT/ICR) or Ion-trap mass spectrometry. In this paper, we show that any of several types of nonlinear phase modulation (preferably, quadratic phase modulation) of the original frequency-domain spectrum before Inverse Fourier transformation can suc-cessfully produce the desired low dynamic range In the time-domain as well as optimally flat frequency-domain transmitter power. Apodlzatlon of the time-domain waveform further smoothes the final excitation power profile. Phasemodulated SWIFT excitation is superior to currently available frequency-sweep excitation for enhanced mass resolution In mass spectrometry/mass spectrometry experiments, en-hanced dynamic range and mass resolution via multlple-lon ejection of abundantIons, more uniform excitation magnitude for improved Isotope-ratio measurements, multlple-lon simultaneous monitoring, and simultaneous exclte/eject combinations. Theoretical and experimental results of various excitation methods are compared.Fourier transform ion cyclotron resonance(FT-ICR) mass spectrometry (1, 2) has advanced to become an extraordinarily versatile mass spectrometric technique offering ultrahigh mass resolution, simultaneous detection of the entire mass spectrum, and an upper mass limit that has yet to be reached (see reviews in Ref 3-10). Currently available excitation methods in FTICR are shown in Figure 1. Single-frequency excitation (top trace of Figure 1) was the method used to produce the very first FT-ICR spectrum (1) and is the principal excitation method inFT-NMR. However, as shown in Figure 1, top right, the “sine” amplitude profile of this frequency-domain excitation spectrum is flat (to within a few percent) only over a small frequency range (ca.±(0.1/T) Hz, in which T is the duration of the time-domain pulse). In general, single-pulse excitation producing nearly flat power over the full chemical mass range (ie, a bandwidth of ca. 3 MHz at 3 T) would require a very short time-domain pulse (ca. 0.1 us) of un-practically large amplitude (> 104 V, for a 1-in. plate separa-tion)(11).