Department of Physics, University of Central Florida, Orlando, Florida 32816, United States.
CREOL, The College of Optics and Photonics, University of Central Florida, Orlando, Florida 32816, United States.
ACS Appl Mater Interfaces. 2024 Aug 28;16(34):45632-45639. doi: 10.1021/acsami.4c06615. Epub 2024 Aug 15.
Monitoring chemical levels is crucial for safeguarding both the environment and public health. Elevated levels of ammonia, for instance, can harm both humans and aquatic ecosystems, often indicating contamination from agriculture, industry, or sewage. Developing portable, high-resolution, and affordable methods for in situ monitoring of ammonia is thus imperative. Plasmonic sensors offer a promising solution, detecting ammonia by correlating changes in their optical response to the target analyte's concentration. While they are highly sensitive and can be fabricated in a variety of portable and user-friendly formats, some still require reagents or expensive optical equipment, which hinder their widespread adoption. Here, we present a self-assembled nanoplasmonic colorimetric sensor capable of directly detecting ammonia concentrations in aqueous matrices. The proposed sensor exploits the plasmonic resonance of the nanostructures to transduce changes in the chemical environment into alterations in color, offering a label-free method for real-time analysis. The sensor is fabricated using a self-assembling technique compatible with low-cost mass production based on aluminum and aluminum oxide, ensuring affordability and avoiding the use of other toxic chemicals. We developed a model to predict ammonia concentrations based on visible color change of the sensor, achieving a detection limit of 8.5 ppm. Furthermore, to address the need for on-site detection, we integrated smartphone technology for real-time color change analysis, eliminating the need for expensive, bulky optical instruments. Indeed, our approach offers a cost-effective, portable, and user-friendly solution for ammonia detection in water without the need for chemical reagents or spectrometers, making it ideal for field applications. Interestingly, this platform extends its applicability beyond ammonia detection, enabling the monitoring of various chemicals using a smartphone, without the need for any additional costly equipment.
监测化学物质水平对于保护环境和公共健康至关重要。例如，氨的含量升高会对人类和水生生态系统造成危害，通常表明其来自农业、工业或污水的污染。因此，开发便携式、高分辨率且经济实惠的现场氨监测方法势在必行。等离子体传感器提供了一种有前途的解决方案，通过将其光学响应的变化与目标分析物的浓度相关联来检测氨。虽然它们具有很高的灵敏度，并且可以以各种便携式和用户友好的格式制造，但有些仍需要试剂或昂贵的光学设备，这阻碍了它们的广泛采用。在这里，我们提出了一种自组装的纳米等离子体比色传感器，能够直接检测水基矩阵中的氨浓度。该传感器利用纳米结构的等离子体共振将化学环境的变化转化为颜色的变化，提供了一种无需标记的实时分析方法。该传感器采用自组装技术制造，与基于铝和氧化铝的低成本大规模生产兼容，确保了可负担性并避免了使用其他有毒化学品。我们开发了一种基于传感器可见颜色变化预测氨浓度的模型，检测限为 8.5ppm。此外，为了满足现场检测的需求，我们集成了智能手机技术进行实时颜色变化分析，无需使用昂贵、庞大的光学仪器。实际上，我们的方法提供了一种经济实惠、便携式且用户友好的水氨检测解决方案，无需使用化学试剂或光谱仪，非常适合现场应用。有趣的是，该平台的适用性不仅限于氨检测，还可以使用智能手机监测各种化学物质，而无需任何额外的昂贵设备。
