Microcapillary electrophoresis (μCE) enables high-resolution separations in miniaturized, automated microfluidic devices. Pairing this powerful separation technique with laser-induced fluorescence (LIF) enables a highly sensitive, quantitative, and compositional analysis of organic molecule monomers and short polymers, which are essential, ubiquitous components of life on Earth. Improving methods for their detection has applications to multiple scientific fields, particularly those related to medicine, industry, and space science. Here, a modular benchtop system using μCE with LIF detection was constructed and tested by analyzing standard amino acid samples of valine, serine, alanine, glycine, glutamic acid, and aspartic acid in multiple borate buffered solutions of increasing concentrations from 10 mM to 50 mM, all pH 9.5. The 35 mM borate buffer solution generated the highest resolution before Joule heating dominated. The limits of detection of alanine and glycine using 35 mM borate buffer were found to be 2.12 nM and 2.91 nM, respectively, comparable to other state-of-the-art μCE-LIF instruments. This benchtop system is amenable to a variety of detectors, including a photomultiplier tube, a silicon photomultiplier, or a spectrometer, and currently employs a spectrometer for facile multi-wavelength detection. Furthermore, the microdevice is easily exchanged to fit the desired application of the system, and optical components within the central filter cube can be easily replaced to target alternative fluorescent dyes. This work represents a significant step forward for the analysis of small organic molecules and biopolymers using μCE-LIF systems.

中文翻译：

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一种模块化、易于使用的微毛细管电泳系统，具有激光诱导荧光，用于痕量有机分子的定量成分分析

微毛细管电泳 (μCE) 可在微型自动化微流体设备中实现高分辨率分离。将这种强大的分离技术与激光诱导荧光 (LIF) 相结合，可以对有机分子单体和短聚合物进行高度灵敏、定量和成分分析，它们是地球上生命中必不可少的、无处不在的组成部分。改进检测方法可应用于多个科学领域，尤其是与医学、工业和空间科学相关的领域。在这里，通过在浓度从 10 mM 到 50 mM 递增的多种硼酸盐缓冲溶液中分析缬氨酸、丝氨酸、丙氨酸、甘氨酸、谷氨酸和天冬氨酸的标准氨基酸样品，构建并测试了使用 μCE 和 LIF 检测的模块化台式系统，所有 pH 值为 9.5。在焦耳加热占主导地位之前，35 mM 硼酸盐缓冲溶液产生了最高分辨率。发现使用 35 mM 硼酸盐缓冲液检测丙氨酸和甘氨酸的极限分别为 2.12 nM 和 2.91 nM，与其他最先进的 μCE-LIF 仪器相当。该台式系统适用于各种检测器，包括光电倍增管、硅光电倍增管或光谱仪，目前使用光谱仪进行简便的多波长检测。此外，微型装置很容易更换以适应系统的所需应用，中央过滤器立方体内的光学组件可以很容易地更换为目标替代荧光染料。这项工作代表了使用 μCE-LIF 系统分析有机小分子和生物聚合物的重要一步。