We introduce an approach for the integration of high performance liquid chromatography and droplet microfluidics on a single high-pressure resistant microfluidic glass chip. By coupling these two functionalities, separated analyte bands eluting from the HPLC column are fractionated into numerous droplets in a continuous flowing oil phase. The compartmentalization of the HPLC-eluate in a segmented flow was performed with droplet sizes of approximately 1 nL and with droplet frequencies reaching up to 45 Hz. This approach prevents peak dispersion and facilitates post column processing of chromatographic fractions on chip. A reliable generation of droplets is also possible in reversed phase gradient elution mode as demonstrated by applying a solvent gradient from 20% to 100% acetonitrile. A chip design with an incorporated dosing unit enabled the directed postcolumn addition of reagents to individual droplet fractions. The capability of this dosing function was successfully evidenced by post column addition of a reagent which quenches the fluorescence signal of the analytes. The chip-integration of gradient HPLC, fractionation, detection and post column addition of reagents opens up new avenues to perform multistep chemical processes on a single lab-on-a-chip device.

中文翻译：

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高压芯片-HPLC和液滴微流体在集成微流体玻璃芯片上的无缝结合

我们介绍了一种在单个耐高压微流体玻璃芯片上集成高效液相色谱和液滴微流体的方法。通过结合这两种功能，将从HPLC色谱柱上洗脱下来的分离的分析物谱带在连续流动的油相中分馏成许多小滴。HPLC洗脱液在分段流中的分隔是在约1 nL的液滴大小和高达45 Hz的液滴频率下进行的。此方法可防止峰分散，并有助于色谱图在芯片上的柱后处理。通过应用20％到100％乙腈的溶剂梯度证明，在反相梯度洗脱模式下也可以可靠地产生液滴。集成了定量给料单元的芯片设计使试剂能够在柱后直接添加到各个液滴级分中。这种配药功能的能力已通过柱后添加试剂来证明，该试剂可淬灭分析物的荧光信号。梯度HPLC的芯片集成，分馏，检测和柱后添加试剂为在单个芯片实验室设备上执行多步化学过程开辟了新途径。