Srinivasan Prabhakaran, P Sivaraman Sushmitha, Mohan Akhila Maheswari, Madhu Deepan Kumar, K Chinaraga Pitchaiah, Rao C V S Brahmananda, Nagarajan Sivaraman, Deivasigamani Prabhakaran
Department of Chemistry, School of Advanced Sciences, Vellore Institute of Technology (VIT), Vellore, Tamil Nadu 632014, India.
Department of Chemistry, K. Ramakrishnan College of Technology, Samayapuram, Tiruchirapalli, Tamil Nadu 621112, India.
J Hazard Mater. 2024 Oct 5;478:135483. doi: 10.1016/j.jhazmat.2024.135483. Epub 2024 Aug 10.
This study presents a distinctive solid-state naked-eye colorimetric sensing approach by encapsulating a chromoionophoric probe onto a hybrid macro-/meso-pore polymer scaffold for fast and selective sensing of ultra-trace Hg(II). The customized structural/surface properties of the poly(VPy-co-TM) monolith are attained by specific proportions of 2-vinylpyridine (VPy), trimethylolpropane trimethacrylate (TM), and pore-tuning solvents. The interconnected porous network of poly(VPy-co-TM), inherent superior surface area and porosity, is captivating for the homogeneous/voluminous incorporation of probe molecules, i.e., 7-((4-methoxyphenyl)diazenyl)quinoline-8-ol (MPDQ), for the target-specific colorimetric detection. The structural morphology, surface topography, and phase characteristics of the bare poly(VPy-co-TM) monolith and MPDQ@poly(VPy-co-TM) sensor are examined using HR-TEM-SAED (High-Resolution Transmission Electron Microscopy - Selected Area Electron Diffraction), FE-SEM-EDAX (Field Emission Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy), XPS (X-ray Photoelectron Spectroscopy), p-XRD (Powder X-Ray Diffraction), FT-IR (Fourier Transform Infrared Spectroscopy), UV-Vis-DRS (Ultraviolet-Visible Diffuse Reflectance Spectroscopy), and BET/BJH (Brunauer-Emmett-Teller / Barrett-Joyner-Halenda) analysis. The distinctive properties of the sensor reveal a constrained geometrical orientation of the MPDQ probe onto the long-range continuous monolithic network of meso-/-macropore template, enabling selective interaction with Hg(II) with peculiar color transfiguration from pale yellow to deep brown. The sensor demonstrates a linear spectral-color alliance in the 0-200 ppb concentration range for Hg(II), with quantification and detection limits of 0.63 and 0.19 ppb. The sensor efficacy is verified using certified contaminated water and tobacco samples, with excellent reusability, reliability, and reproducibility of ≥ 99.23 % (RSD ≤1.89 %) and ≥ 99.19 % (RSD ≤1.94 %) of Hg(II), respectively.
本研究提出了一种独特的固态裸眼比色传感方法，即将一种发色离子载体探针封装在一种宏观/介孔混合聚合物支架上，用于快速、选择性地检测超痕量汞（II）。聚（VPy-co-TM）整体材料的定制结构/表面性质是通过2-乙烯基吡啶（VPy）、三羟甲基丙烷三甲基丙烯酸酯（TM）和孔径调节溶剂的特定比例来实现的。聚（VPy-co-TM）相互连接的多孔网络、固有的高比表面积和孔隙率，对于探针分子即7-（（4-甲氧基苯基）重氮基）喹啉-8-醇（MPDQ）的均匀/大量掺入具有吸引力，用于目标特异性比色检测。使用高分辨率透射电子显微镜-选区电子衍射（HR-TEM-SAED）、场发射扫描电子显微镜-能谱仪（FE-SEM-EDAX）、X射线光电子能谱（XPS）、粉末X射线衍射（p-XRD）、傅里叶变换红外光谱（FT-IR）、紫外-可见漫反射光谱（UV-Vis-DRS）和BET/BJH（布鲁诺尔-埃米特-特勒/巴雷特-乔伊纳-哈伦达）分析来研究裸聚（VPy-co-TM）整体材料和MPDQ@聚（VPy-co-TM）传感器的结构形态、表面形貌和相特征。该传感器的独特性质揭示了MPDQ探针在介孔/大孔模板的长程连续整体网络上的受限几何取向，使得能够与汞（II）进行选择性相互作用，并伴随着从浅黄色到深棕色的特殊颜色变化。该传感器在汞（II）浓度为0-200 ppb范围内呈现线性光谱-颜色关联，定量限和检测限分别为0.63和0.19 ppb。使用经认证的受污染水和烟草样品验证了该传感器的效能，汞（II）的可重复使用性、可靠性和再现性分别极佳，≥99.23%（相对标准偏差≤1.89%）和≥99.19%（相对标准偏差≤1.94%）。
