Electronic tongues (e-tongues) are promising analytical devices for a variety of applications to address the challenges of quality control in water monitoring and industries of foods, beverages, and pharmaceuticals. A crucial drawback in the current e-tongues is the need to recalibrate the device when one or more sensing units (usually with modified surface) are replaced. Another downside is the necessity to perform subsequent surface modifications and analyses to each of the diverse sensing units, undermining the simplicity and velocity of the method. These features have prevented widespread commercial use of the e-tongues. In this paper, we introduce a microfluidic e-tongue that overcomes all such limitations. The key principle of global selectivity of the e-tongue was achieved by recording only a single response, namely, the equivalent admittance spectrum of an association of resistors in parallel. Such resistors consisted of five nonfunctionalized stainless steel microwires (sensing units), which were short-circuited and coated with gold, platinum, nickel, iron, and aluminum oxide films. The microwires were inserted in a chip composed of a single piece of polydimethylsiloxane (PDMS). Using impedance spectroscopy, the e-tongue was successfully applied in classification of basic tastes at a concentration below the threshold for the human tongue. In addition, our chip allowed the distinction of various chemicals used in oil industry. Finally, our cleanroom-free prototyping allows the mass production of chips with easily replaceable and reproducible sensing units. Hence, one can now envisage the widespread dissemination of e-tongues with fast and reproducible data.

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基于单一响应的无功能微流控电子舌

电子舌（电子舌）是有前途的分析设备，可用于各种应用，以应对水监控以及食品，饮料和制药行业中质量控制的挑战。当前电子舌上的一个关键缺点是，当更换一个或多个传感单元（通常具有改良的表面）时，需要重新校准设备。另一个缺点是必须对每个不同的传感单元进行后续的表面修改和分析，从而破坏了该方法的简便性和速度。这些特征阻止了电子舌的广泛商业使用。在本文中，我们介绍了一种克服所有此类限制的微流体电子舌。电子舌的全球选择性的关键原则是通过仅记录一个响应来实现的，即，并联电阻组合的等效导纳频谱。此类电阻器由五根未经功能化的不锈钢微线（传感单元）组成，它们经过短路并涂有金，铂，镍，铁和氧化铝膜。将微丝插入由单片聚二甲基硅氧烷（PDMS）组成的芯片中。使用阻抗光谱法，电子舌已成功应用于基本口味的分类，其浓度低于人类舌头的阈值。此外，我们的芯片还可以区分石油工业中使用的各种化学品。最后，我们的无尘室原型制造允许使用易于更换和可重现的传感单元进行芯片的大量生产。因此，现在可以设想以快速且可复制的数据广泛传播电子舌。