Knežević Sara, Jovanović Nataša Terzić, Vlahović Filip, Ajdačić Vladimir, Costache Vlad, Vidić Jasmina, Opsenica Igor, Stanković Dalibor
Faculty of Chemistry, University of Belgrade, Studentski trg 12-16, 11000 Belgrade, Serbia; Univ. Bordeaux, CNRS, Bordeaux INP, Institut des Sciences Moléculaires, UMR 5255, F-33400 Talence, France.
Scientific Institution, Institute of Chemistry, Technology and Metallurgy, National Institute University of Belgrade, Belgrade, Serbia.
Chemosphere. 2023 Nov;341:139930. doi: 10.1016/j.chemosphere.2023.139930. Epub 2023 Aug 31.
Covalent organic frameworks (COFs) are emerging as promising sensing materials due to their controllable structure and function properties, as well as excellent physicochemical characteristics. Here, specific interactions between a triazine-based COF and a mass-used herbicide - glyphosate (GLY) have been utilized to design a disposable sensing platform for GLY detection. This herbicide has been extensively used for decades, however, its harmful environmental impact and toxicity to humans have been recently proven, conditioning the necessity for the strict control and monitoring of its use and its presence in soil, water, and food. Glyphosate is an organophosphorus compound, and its detection in complex matrices usually requires laborious pretreatment. Here, we developed a direct, miniaturized, robust, and green approach for disposable electrochemical sensing of glyphosate, utilizing COF's ability to selectively capture and concentrate negatively charged glyphosate molecules inside its nanopores. This process generates the concentration gradient of GLY, accelerating its diffusion towards the electrode surface. Simultaneously, specific COF-glyphosate binding catalyses the oxidative cleavage of the C-P bond and, together with pore nanoconfinement, enables sensitive glyphosate detection. Detailed sensing principles and selectiveness were scrutinized using DFT-based modelling. The proposed electrochemical method has a linear working range from 0.1 μM to 10 μM, a low limit of detection of 96 nM, and a limit of quantification of 320 nM. The elaborated sensing approach is viable for use in real sample matrices and tested for GLY determination in soil and water samples, without pretreatment, preparation, or purification. The results showed the practical usefulness of the sensor in the real sample analysis and suggested its suitability for possible out-of-laboratory sensing.
共价有机框架（COFs）因其可控的结构和功能特性以及优异的物理化学特性，正成为有前景的传感材料。在此，基于三嗪的COF与一种广泛使用的除草剂——草甘膦（GLY）之间的特定相互作用被用于设计一个用于检测GLY的一次性传感平台。这种除草剂已经广泛使用了数十年，然而，其对环境的有害影响以及对人类的毒性最近已得到证实，这使得严格控制和监测其使用以及在土壤、水和食物中的存在成为必要。草甘膦是一种有机磷化合物，在复杂基质中对其进行检测通常需要繁琐的预处理。在此，我们开发了一种直接、小型化、稳健且绿色的一次性电化学传感草甘膦的方法，利用COF选择性捕获并浓缩带负电荷的草甘膦分子在其纳米孔内的能力。这个过程产生了GLY的浓度梯度，加速了其向电极表面的扩散。同时，特定的COF - 草甘膦结合催化了C - P键的氧化裂解，并且与孔纳米限域一起，实现了对草甘膦的灵敏检测。使用基于密度泛函理论（DFT）的建模仔细研究了详细的传感原理和选择性。所提出的电化学方法的线性工作范围为0.1 μM至10 μM，检测下限低至96 nM，定量限为320 nM。所阐述的传感方法可用于实际样品基质，并且在未经预处理、制备或纯化的情况下对土壤和水样中的GLY测定进行了测试。结果表明该传感器在实际样品分析中的实用性，并表明其适用于可能的实验室外传感。
