Nagornov Konstantin O, Kozhinov Anton N, Tsybin Yury O
Spectroswiss Sàrl, EPFL Innovation Park, 1015, Lausanne, Switzerland.
J Am Soc Mass Spectrom. 2017 Apr;28(4):768-780. doi: 10.1007/s13361-017-1598-y. Epub 2017 Feb 17.
The phenomenon of ion cyclotron resonance allows for determining mass-to-charge ratio, m/z, of an ensemble of ions by means of measurements of their cyclotron frequency, ω . In Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS), the ω quantity is usually unavailable for direct measurements: the resonant state is located close to the reduced cyclotron frequency (ω), whereas the ω and the corresponding m/z values may be calculated via theoretical derivation from an experimental estimate of the ω quantity. Here, we describe an experimental observation of a new resonant state, which is located close to the ω frequency and is established because of azimuthally-dependent trapping electric fields of the recently developed ICR cells with narrow aperture detection electrodes. We show that in mass spectra, peaks close to ω frequencies can be reduced to negligible levels relative to peaks close to ω frequencies. Due to reduced errors with which the ω quantity is obtained, the new resonance provides a means of cyclotron frequency measurements with precision greater than that achieved when ω frequency peaks are employed. The described phenomenon may be considered for a development into an FT-ICR MS technology with increased mass accuracy for applications in basic research, life, and environmental sciences. Graphical Abstract ᅟ.
离子回旋共振现象使得通过测量离子的回旋频率ω来确定离子集合的质荷比m/z成为可能。在傅里叶变换离子回旋共振质谱（FT-ICR MS）中，ω量通常无法直接测量：共振状态位于接近折合回旋频率（ω）处，而ω和相应的m/z值可通过从ω量的实验估计值进行理论推导来计算。在此，我们描述了一种新共振状态的实验观测，该共振状态位于接近ω频率处，并且是由于最近开发的带有窄孔径检测电极的ICR池的方位角相关捕获电场而形成的。我们表明，在质谱中，相对于接近ω频率的峰，接近ω频率的峰可降低到可忽略的水平。由于获得ω量时误差的减小，新的共振提供了一种回旋频率测量方法，其精度高于使用ω频率峰时所达到的精度。所描述的现象可考虑发展成为一种在基础研究、生命科学和环境科学应用中具有更高质量精度的FT-ICR MS技术。图形摘要ᅟ 。
