B Oliveira Pablo R, Leyva Dennys, V Tose Lilian, Weisbrod Chad, Kozhinov Anton N, Nagornov Konstantin O, Tsybin Yury O, Fernandez-Lima Francisco
Department of Chemistry and Biochemistry, Florida International University, Miami, Florida 33199, United States.
Institute of Environment, Florida International University, Miami, Florida 33199, United States.
J Am Soc Mass Spectrom. 2024 Oct 2;35(10):2400-2407. doi: 10.1021/jasms.4c00232. Epub 2024 Sep 12.
The molecular level characterization of complex mixtures remains an analytical challenge. We have shown that the integration of complementary, high-resolution, gas-phase separations allows for chemical formula level isomeric content description. In the current work, we revisited the current challenges associated with the analysis of dissolved organic matter using high-resolution trapped ion mobility separation (TIMS) and Fourier transform ion cyclotron resonance mass spectrometry (FT-ICR MS). In particular, we evaluated the separation capabilities provided by TIMS-MS compared to MS alone, the use of ICR complementary data acquisition (DAQ) systems and transient processing strategies, ICR cell geometries (e.g., Infinity cell vs harmonized cell), and magnetic field strengths (7 T vs 9.4 T vs 21 T) for the case of a Harney River DOM sample. Results showed that the external high-performance DAQ enables direct representation of mass spectra in absorption mode FT (aFT), doubling the MS resolution compared to the default magnitude mode FT (mFT). Changes between half- vs full-apodization result in greater MS signal/noise vs superior MS resolving power (RP); in the case of DOM analysis, a 45% increase in assigned formulas is observed when employing the DAQ half (Kaiser-type)-apodization window and aFT when compared to the default instrument mFT. Results showed the advantages of reprocessing 2D-TIMS-FT-ICR MS data with higher RP and magnetic field chemical formulas generated list acquired (e.g., 21 T led to a 24% increase in isomers reported) or the implementation of alternative strategies.
复杂混合物的分子水平表征仍然是一项分析挑战。我们已经表明，互补的高分辨率气相分离技术的整合能够实现化学式水平的异构体含量描述。在当前工作中，我们重新审视了使用高分辨率捕集离子淌度分离（TIMS）和傅里叶变换离子回旋共振质谱（FT-ICR MS）分析溶解有机物时面临的挑战。特别是，我们评估了与单独使用质谱相比，TIMS-MS提供的分离能力、ICR互补数据采集（DAQ）系统和瞬态处理策略的使用、ICR池几何结构（例如，Infinity池与协调池）以及针对哈尼河DOM样品的磁场强度（7 T对9.4 T对21 T）。结果表明，外部高性能DAQ能够以吸收模式傅里叶变换（aFT）直接呈现质谱图，与默认的幅度模式傅里叶变换（mFT）相比，质谱分辨率提高了一倍。半窗与全窗变迹之间的变化会导致更高的质谱信号/噪声与更好的质谱分辨能力（RP）；在DOM分析中，与默认仪器mFT相比，采用DAQ半窗（Kaiser型）变迹窗口和aFT时，分配的分子式数量增加了45%。结果显示了对具有更高RP和磁场的2D-TIMS-FT-ICR MS数据进行重新处理（例如，21 T导致报告的异构体数量增加24%）或实施替代策略的优势。
