Concentration sensitivity is a key performance indicator for analytical techniques including for capillary electrophoresis‐mass spectrometry (CE–MS) with electrospray ionization (ESI). In this study, a flow‐through microvial interface was used to couple CE with MS and improve the ESI stability and detection sensitivity. By infusing a peptide mixture through the interface into an MS detector at a typical flow rate for CE‐MS analysis, the spatial region near the interface was mapped for MS signal intensity. When the sprayer tip was within a 6 × 6.5 × 5 mm region in front of the MS inlet, the ESI was stable with no significant loss of signal intensity for ions with m/z 239. Finite element simulations showed that the average electric field strength at the emitter tip did not change significantly with minor changes in emitter tip location. Experiments were conducted with four different mass spectrometer platforms coupled to CE via the flow‐through microvial interface. Key performance indicators, that is, limit of detection (LOD) and linearity of calibration curves were measured for nine amino acids and five peptides. Inter‐ and intraday reproducibility were also tested. The results were shown to be suitable for quantification when internal standards were used.

中文翻译：

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使用流通微瓶接口的毛细管电泳-质谱法中的电喷雾电离稳定性和浓度灵敏度

浓度灵敏度是分析技术的关键性能指标，包括带电喷雾电离 (ESI) 的毛细管电泳质谱 (CE-MS)。在本研究中，流通微瓶接口用于将 CE 与 MS 耦合并提高 ESI 稳定性和检测灵敏度。通过以典型的 CE-MS 分析流速将肽混合物通过界面注入 MS 检测器，界面附近的空间区域被映射为 MS 信号强度。当喷雾器尖端位于 MS 入口前 6 × 6.5 × 5 mm 区域内时，ESI 稳定，m/z离子的信号强度没有明显损失239. 有限元模拟表明，发射器尖端的平均电场强度不会随着发射器尖端位置的微小变化而发生显着变化。使用通过流通微瓶接口与 CE 耦合的四种不同质谱仪平台进行了实验。关键性能指标，即检测限 (LOD) 和校准曲线的线性度对 9 个氨基酸和 5 个肽段进行了测量。还测试了日间和日内重现性。当使用内标时，结果显示适用于定量。