Reduction of signal suppression effects in ESI-MS using a nanosplitting device
Reduction of signal suppression effects in ESI-MS using a nanosplitting device
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DOI：
10.1021/ac010501i
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发表时间：
2001-12-01
影响因子：
7.4
通讯作者：
Vouros, P
中科院分区：
文献类型：
--
作者：
Gangl, ET;Annan, M;Vouros, P
电喷雾电离质谱是鉴定和定量生物体液中药物代谢物的重要工具。然而，在许多情况下，这些液体中存在的基质成分会干扰分析物检测并妨碍获得准确或完整的结果。在某些情况下，基质可以将电离抑制到 MS 完全检测不到分析物的程度。在这项工作中，我们研究了大幅减少进入 MS 的流量如何影响电离和离子转移效率。构建了柱后同心分流装置，以允许在一定流速范围（0.1-200 μL/min）内测量分析物信号和电离抑制。使用该装置，在分析实验中测量了流速对信号强度和电离抑制的影响，包括流动注射分析 MS、柱后添加 LC-MS 以及对大鼠肝微粒体产生的代谢物的在线 LC-MS 分析。用于提供 0.1 μL/min 流量的装置被称为纳米分流器，因为它实现了高分流比 (2000:1)，产生的流速与纳米电喷雾中观察到的流速相当。纳米分流器以高保真度保持色谱完整性，并允许在一定流速范围（0.1-200 μL/min）内直接比较分析物信号。当比较 200 与 0.1 μL/min 流速下的性能时，观察到浓度和质量灵敏度的显着改善以及信号抑制的减少。使用这种专门设计的同心分流装置，超低流量 ESI 的优势可以轻松地应用于大口径色谱应用。
Electrospray ionization mass spectrometry is a valuable tool in the identification and quantification of drug metabolites in biological fluids. However, there are many instances where matrix components present in these fluids interfere with analyte detection and prevent the acquisition of accurate or complete results. In some instances, the matrix can suppress ionization to such an extent that analytes are completely undetectable by MS. In this work, we investigate how ionization and ion-transfer efficiencies are affected by drastically reducing the flow into the MS. A postcolumn concentric flow-splitting device was constructed to allow the measurement of analyte signal and ionization suppression across a range of flow rates (0.1-200 muL/min). Using this device, the effects of flow rate on signal intensity and ionization suppression were measured in analytical experiments that included flow injection analysis MS, postcolumn addition LC-MS, and on-line LC-MS analysis of metabolites generated from rat liver microsomes. The device used to deliver 0.1 muL/min flows is referred to as a nanosplitter because it achieved high split ratios (2000: 1), producing flow rates comparable to those observed in nanoelectrospray. The nanosplitter maintained chromatographic integrity with high fidelity and allowed the direct comparison of analyte signal across a range of flow rates (0.1-200 muL/min). A significant improvement in concentration and mass sensitivity as well as a reduction in signal suppression is observed when the performance at 200 versus 0.1 muL/min flow rate is compared. Using this specially designed concentric splitting device, the advantages of ultralow flow ESI were easily exploited for applications employing large bore chromatography.