Green leaf volatiles (GLVs) are organic compounds emitted by plants in response to insect attacks, offering early detection potential. Current GLV detection methods like gas chromatography–mass spectroscopy (GC-MS) are costly and complex and lack real-time monitoring capability. There is an unmet need for affordable and portable sensors with high sensitivity to monitor GLVs in real time. In this study, we developed a novel sensor capable of capturing piezoelectric and colorimetric signals for the sensitive and selective detection of 1-hexanol, a well-known green leaf volatile. We used a piezoelectric micro quartz tuning fork (MQTF) as the multifunctional transducer. The MQTF’s two prongs were coated with a metal–organic framework (MOF)-thymol blue hybrid sensing material, enabling detection through both color change and resonating frequency shift upon 1-hexanol binding. MOFs offer a high surface area and tunable pore size, which enhance sensor sensitivity and selectivity. The sensor’s frequency shift indicates mass change due to 1-hexanol binding to MOFs, while the colorimetric sensing signal relies on thymol blue’s reaction with 1-hexanol. Our test results demonstrate the sensor’s ability to detect 1-hexanol from 62.5 ppb to 250 ppm with high sensitivity and selectivity when the colorimetric and piezoelectric sensing signals are integrated. Due to its compact size, affordability, easy fabrication, wide detection range, and high sensitivity and selectivity, this colorimetric-piezoelectric sensor could serve as an effective tool for early detection of insect herbivore attacks and timely crop protection strategies.

中文翻译：

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基于金属-有机框架 （MOF） 的压电-比色混合传感器，用于监测绿叶挥发物


绿叶挥发物 （GLV） 是植物为应对昆虫攻击而释放的有机化合物，具有早期检测潜力。目前的 GLV 检测方法，如气相色谱-质谱 （GC-MS），成本高昂且复杂，并且缺乏实时监测能力。对经济实惠、高灵敏度的便携式传感器进行实时监测 GLV 的需求尚未得到满足。在这项研究中，我们开发了一种能够捕获压电和比色信号的新型传感器，用于灵敏和选择性地检测 1-己醇，一种众所周知的绿叶挥发物。我们使用压电微石英音叉 （MQTF） 作为多功能传感器。MQTF 的两个插脚涂有金属-有机框架 （MOF）-百里酚蓝混合传感材料，可通过 1-己醇结合后的颜色变化和共振频移进行检测。MOF 具有高表面积和可调孔径，可增强传感器的灵敏度和选择性。传感器的频移表示由于 1-己醇与 MOF 结合引起的质量变化，而比色传感信号依赖于百里酚蓝与 1-己醇的反应。我们的测试结果表明，当比色和压电传感信号集成时，传感器能够以高灵敏度和选择性检测 62.5 ppb 至 250 ppm 的 1-己醇。由于其体积小、价格合理、易于制造、检测范围广以及灵敏度和选择性高，这种比色压电传感器可以作为早期检测昆虫食草动物攻击和及时作物保护策略的有效工具。