Microfluidic amperometric detectors often include a reservoir to house auxiliary and reference electrodes, making subsequent detection downstream challenging. Here, we present an in-line microfluidic device with amperometric detection that incorporates a three-electrode set-up, made possible by threading electrodes into a 3D-printed flow cell. The electrodes consist of a commercially available threaded reference electrode and electrodes fabricated in commercially available fittings. This approach centers the working electrode in the fluidic channel enabling the use of a pillar working electrode that is shown to increase sensitivity, as compared to a traditional thin-layer electrode. In addition, the working and auxiliary electrodes can be directly opposed, with this configuration leading to a more uniform potential being applied to the working electrode as well as fewer issues with any iR drop. To demonstrate the ability to incorporate a separate mode of detection downstream from the electrochemical flow cell, the device is modified to include a mixing T for introduction of reagents for chemiluminescent detection of ATP (via the luciferin–luciferase reaction), leading to a single 3D-printed device that can be used to detect norepinephrine and ATP, nearly simultaneously, by amperometry and chemiluminescence, respectively. This approach opens numerous possibilities, where microfluidics with in-line amperometry can be used in continuous circulation studies or in conjunction with other downstream detection events to study complex systems.

中文翻译：

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具有在线安培检测功能的3D打印微流控设备，还可以进行多模式检测。

微流体安培检测器通常包括一个容纳辅助电极和参比电极的容器，这使得后续的下游检测变得困难。在这里，我们介绍了一种带有安培检测功能的在线微流体装置，该装置结合了三电极设置，可通过将电极穿入3D打印的流通池中来实现。电极由市售的螺纹参比电极和以市售的配件制成的电极组成。这种方法使工作电极在流体通道中居中，从而可以使用柱状工作电极，与传统的薄层电极相比，柱状工作电极可以提高灵敏度。此外，工作电极和辅助电极可以直接相对，iR下降。为了展示在电化学流动池下游整合独立检测模式的能力，对该设备进行了修改，使其包括混合T，用于引入用于化学发光检测ATP的试剂（通过荧光素-荧光素酶反应），从而产生单个3D -可分别通过电流分析法和化学发光法同时检测去甲肾上腺素和ATP的装置。这种方法开辟了许多可能性，其中可以将带有在线安培计的微流控技术用于连续循环研究或与其他下游检测事件结合使用，以研究复杂的系统。