Boeira Carla D, Leidens Leonardo M, Carvalho Costa Endel E, Gonçalves Maria H, Perillo Amanda S, Ferraz Felipe A, Marchi Maria C, Shimizu Flavio M, Amaral Lucas R, Alvarez Fernando, Riul Antonio
Instituto de Física 'Gleb Wataghin' (IFGW), Universidade Estadual de Campinas (UNICAMP), Campinas, São Paulo 13083-970, Brazil.
Universidad de Buenos Aires, Facultad de Ciencias Exactas y Naturales, Departamento de Química Inorgánica, Analítica y Química Física, Buenos Aires C1428EGA, Argentina.
ACS Sens. 2025 Aug 22;10(8):5760-5771. doi: 10.1021/acssensors.5c00921. Epub 2025 Aug 12.
The growing global demand for food requires optimizing agricultural practices and more rational use of natural resources without expanding cropping areas. Precision agriculture (PA) tools are essential for accurately applying fertilizers and herbicides, reducing costs, and avoiding environmental impacts. Standard macronutrient mapping methods are costly and time-consuming, limiting denser sampling collection in the field. Consequently, devices employing new materials with specific properties matching sensitivity to agricultural nutrients, robustness to face intensive climatic variations, and economical manufacturing viability are mandatory. In this sense, microfluidic impedimetric e-tongues have emerged as practical tools in PA due to their high sensitivity, adaptability, affordability, and ease of use. These sensors provide rapid qualitative and quantitative results in liquid media, with applications extending to food analysis, environmental monitoring, and biosensing. Here, metallic nitride thin films (CrN, BN, and TiN) deposited via physical vapor deposition (PVD) using the glancing angle deposition (GLAD) technique are applied as sensing units presenting high sensitivity, controlled micro- and nanostructures, durability, reproducibility, and mechanical robustness, essential characteristics for future on-site soil analyses. The GLAD technique allows precise control over the micro- and nanostructures deposited on gold interdigitated electrodes to create molecular sieves for a possible capture of target species (e.g., K, Na, Mg, Ca, PO) from soil samples. We demonstrate the feasibility of using distinct nitrides as sensing units in a microfluidic e-tongue tested with soil samples with distinct compositions diluted in water without pretreatments. The sensor successfully differentiated all samples tested, showing higher K and Mg macronutrient resolution. These findings demonstrate the high potential to detect minute changes (<1 mmol·L) in soil fertilization, with results compared by four prediction models, paving the way for future in situ analyses envisaging a controlled delivery of macronutrients during fertilization.
全球对粮食的需求不断增长，这就要求在不扩大种植面积的情况下优化农业生产方式并更合理地利用自然资源。精准农业（PA）工具对于准确施用肥料和除草剂、降低成本以及避免环境影响至关重要。标准的常量营养素测绘方法成本高且耗时，限制了田间更密集的采样收集。因此，必须采用具有特定特性的新材料制成的设备，这些特性包括对农业养分的敏感性、应对剧烈气候变化的稳健性以及经济的制造可行性。从这个意义上说，微流控阻抗电子舌因其高灵敏度、适应性、可承受性和易用性，已成为精准农业中的实用工具。这些传感器可在液体介质中快速提供定性和定量结果，其应用范围扩展到食品分析、环境监测和生物传感。在此，通过物理气相沉积（PVD）使用掠角沉积（GLAD）技术沉积的金属氮化物薄膜（CrN、BN和TiN）被用作传感单元，具有高灵敏度、可控的微观和纳米结构、耐久性、可重复性和机械稳健性，这些都是未来现场土壤分析的基本特性。GLAD技术允许精确控制沉积在金叉指电极上的微观和纳米结构，以创建分子筛，用于从土壤样品中捕获目标物种（例如K、Na、Mg、Ca、PO）。我们证明了在未经预处理的情况下，将不同的氮化物用作微流控电子舌中的传感单元，并用不同成分的土壤样品在水中稀释后进行测试的可行性。该传感器成功区分了所有测试样品，显示出对K和Mg常量营养素更高的分辨率。这些发现证明了检测土壤施肥中微小变化（<1 mmol·L）的巨大潜力，通过四种预测模型对结果进行了比较，为未来在施肥过程中设想的常量营养素控制输送的原位分析铺平了道路。
