Ion signal detection at the true (unperturbed) cyclotron frequency instead of the conventional reduced cyclotron frequency has remained a formidable challenge since the inception of Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). Recently, routine FT-ICR MS at the true cyclotron frequency has become a reality with the implementation of ICR cells with narrow aperture detection electrodes (NADEL). Here, we describe the development and implementation of the next generation of these cells, namely a 2xNADEL ICR cell, which comprises four flat detect and four ~45 degrees cylindrical excite electrodes, enabling independent ion excitation and quadrupolar ion detection. The performance of the 2xNADEL ICR cell was evaluated on two commercial FT-ICR MS platforms, 10 T LTQ FT from Thermo Scientific and 9.4 T SolariX XR from Bruker Daltonics. The cells provided accurate mass measurements in the analyses of singly and multiply charged peptides (root mean square, RMS, mass error Δm/m of 30 ppb), proteins (Δm/m = 200 ppb), and petroleum fractions (Δm/m < 200 ppb). Due to the reduced influence of measured frequency on the space charge and external (trapping) electric fields, the 2xNADEL ICR cells exhibited stable performance in a wide range of trapping potentials (1-20 V). Similarly, in a 13-hour rat brain MALDI imaging experiment, the RMS mass error did not exceed 600 ppb even for low signal-to-noise ratio analyte peaks. Notably, the same set of calibration constants was applicable to Fourier spectra in all pixels, reducing the need for recalibration at the individual pixel level. Overall, these results support further experimental development and fundamentals investigation of this promising technology.

中文翻译：

---

具有四极离子检测功能的窄孔检测电极ICR电池，用于回旋加速器频率下的FT-ICR MS。

自从傅里叶变换离子回旋共振质谱仪（FT-ICR MS）诞生以来，在真正的（无扰动）回旋加速器频率而不是传统的降低的回旋加速器频率进行离子信号检测一直是一个艰巨的挑战。近年来，随着带有窄孔检测电极（NADEL）的ICR电池的实现，常规的FT-ICR MS已成为现实。在这里，我们描述了下一代此类电池的开发和实现，即2xNADEL ICR电池，该电池包括四个平面检测和四个〜45度的圆柱状激发电极，可实现独立的离子激发和四极离子检测。在两个商业FT-ICR MS平台，Thermo Scientific的10 T LTQ FT和9的商业FT-ICR MS平台上评估了2xNADEL ICR电池的性能。来自Bruker Daltonics的4 T SolariX XR。这些细胞在分析单电荷和多电荷肽（均方根，RMS，质量误差Δm/ m为30 ppb），蛋白质（Δm/ m = 200 ppb）和石油馏分（Δm/ m < 200 ppb）。由于降低了测量频率对空间电荷和外部（捕获）电场的影响，因此2xNADEL ICR电池在宽范围的捕获电势（1-20 V）中表现出稳定的性能。同样，在长达13小时的大鼠大脑MALDI成像实验中，即使对于低信噪比分析物峰，RMS质量误差也不会超过600 ppb。值得注意的是，同一组校准常数适用于所有像素的傅立叶光谱，从而减少了在单个像素级别进行重新校准的需要。总体，