The monitoring of different harmful gases such as volatile organic compounds (VOCs) is essential to ensure the air quality and population security. Therefore, the development of rapid, cheap and accurate sensing devices is a key to enable continuous monitoring of the air quality. On this matter, magnetoelastic sensors, particularly the rhombus-shaped ones, have become an interesting alternative to the current sensing systems because, besides exhibiting a fast response, they present a wireless sensing capacity. Moreover, the addition of metal–organic frameworks (MOFs) as highly porous active layers to different sensing devices endows them with the desired adsorption capacity and selectivity to detect VOCs. Therefore, in this work, we explore the performance of a highly sensitive rhombic magnetoelastic Metglas 2826 MB resonator functionalized with a high-toluene adsorption capacity MOF layer (i.e. UiO66-NH₂) for its wireless detection. Our findings confirm the feasibility of the Metglas/MOF system for fast and reversible toluene detection, being key the control of the active layer mass to improve its sensitivity. From the toluene sensing experiments, a maximum sensitivity of 0.27 Hz ppm⁻¹ was determined. Finally, the sensor selectivity has been evaluated through the analysis of the sensor response to different atmospheres (water, acetone, ethanol and toluene) and it was observed that the sensor presents an enhanced selectivity towards toluene. Given the structural diversity and chemical tunability of MOF materials, their use as active sorbent layers in resonator systems together with the possibility to further optimize the resonator geometry to improve the sensitivity and the MOF structure to gain more selectivity, opens up the possibility for the facile and straightforward designing of future wireless sensors for any kind of environmentally hazardous substance.

中文翻译：

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菱形磁弹性/金属有机框架功能的共振器，用于高灵敏度的甲苯检测

监测各种有害气体（例如挥发性有机化合物（VOC））对于确保空气质量和人口安全至关重要。因此，快速，廉价和准确的传感设备的开发是实现连续监测空气质量的关键。在这个问题上，磁弹性传感器，尤其是菱形传感器，已经成为电流传感系统的有趣替代，因为除了表现出快速响应之外，它们还具有无线传感能力。此外，将金属有机框架（MOF）作为高度多孔的活性层添加到不同的传感设备中，使其具有所需的吸附能力和检测VOC的选择性。因此，在这项工作中例如UiO66-NH ₂）进行无线检测。我们的发现证实了Metglas / MOF系统用于快速和可逆甲苯检测的可行性，这是控制活性层质量以提高其灵敏度的关键。根据甲苯感测实验，最大灵敏度为0.27 Hz ppm ^-1被确定。最后，通过分析传感器对不同气氛（水，丙酮，乙醇和甲苯）的响应，评估了传感器的选择性，并且观察到传感器对甲苯的选择性增强。考虑到MOF材料的结构多样性和化学可调性，它们在谐振器系统中用作活性吸附剂层，并有可能进一步优化谐振器的几何形状以提高灵敏度，而MOF结构获得更多的选择性，为这种方法提供了可能性以及针对各种对环境有害物质的未来无线传感器的直接设计。