Shahamirifard S A R, Ghaedi M, Montazerozohori M, Masoudiasl A
Chemistry Department, Yasouj University, Yasouj 75918-74831, Iran.
Photochem Photobiol Sci. 2018 Feb 14;17(2):245-255. doi: 10.1039/c7pp00454k.
In this work, the use of carbon dots (CDs) as a complexing agent and sensitizer in a polymeric matrix for determination of copper(ii) by UV-vis spectroscopy is reported for the first time. A new and highly selective Schiff base, namely, (N',N'''E,N',N'''E)-N',N'''-((((2-hydroxypropane-1,3-diyl)bis(oxy))bis(2,1-phenylene))bis(methan-ylylidene))di(isonicotinohydrazide) (NHBMDI), was also incorporated in the polymeric matrix. For the first time, the membrane composition of the proposed optical sensor including NHBMDI as the ionophore, tetraphenylborate (NaTPB) as the anionic additive, dibutyl phthalate (DBP) as the plasticizer and polyvinyl chloride (PVC) as the immobilizer was optimized through central composite design combined with the desirability function approach (DFA) because this method saves material and time consumption and is therefore cost effective. The synthesized CDs were characterized by transmission electron microscopy (TEM) and scanning electron microscopy (SEM). The fluorescence quantum yield of the synthesized CDs was found to be 6.4% by using quinine sulfate as the reference. The characterization of the prepared membrane sensor was investigated by field emission scanning electron microscope (FE-SEM) and atomic force microscopy (AFM).The response of the optode was based on the strong absorbance of NHBMDI and CDs upon exposure to Cu(ii) ions with the maximum wavelength at 371 nm. The proposed sensor exhibited a linear response in the concentration range of 1.2 × 10-4.56 × 10 mol L with a detection limit of 7.1 × 10 mol L, which is lower than U.S. Environmental Protection Agency's defined limit (20 μM). Furthermore, the proposed optode displayed good selectivity toward Cu(ii) ions in comparison with common coexisting cations with satisfactory repeatability and reproducibility. The sensor was applied successfully for determination of copper(ii) ions in water samples.
在本工作中，首次报道了在聚合物基质中使用碳点（CDs）作为络合剂和敏化剂，通过紫外可见光谱法测定铜（II）。一种新型且具有高选择性的席夫碱，即（N'，N'''E，N'，N'''E）-N'，N'''-（（（（2-羟基丙烷-1,3-二基）双（氧基））双（2,1-亚苯基））双（亚甲基））二（异烟酰肼）（NHBMDI），也被掺入到聚合物基质中。首次通过中心复合设计结合期望函数法（DFA）对所提出的光学传感器的膜组成进行了优化，该光学传感器包括作为离子载体的NHBMDI、作为阴离子添加剂的四苯基硼酸钠（NaTPB）、作为增塑剂的邻苯二甲酸二丁酯（DBP）以及作为固定剂的聚氯乙烯（PVC），因为这种方法节省材料和时间消耗，因此具有成本效益。通过透射电子显微镜（TEM）和扫描电子显微镜（SEM）对合成的碳点进行了表征。以硫酸奎宁为参比，测得合成碳点的荧光量子产率为6.4%。通过场发射扫描电子显微镜（FE-SEM）和原子力显微镜（AFM）对制备的膜传感器进行了表征研究。该光极的响应基于NHBMDI和碳点在暴露于铜（II）离子时的强吸收，最大波长为371nm。所提出的传感器在1.2×10⁻⁴ - 5.6×10⁻⁴mol/L的浓度范围内呈现线性响应，检测限为7.1×10⁻⁵mol/L，低于美国环境保护局规定的限值（20μM）。此外，与常见的共存阳离子相比，所提出的光极对铜（II）离子表现出良好的选择性，具有令人满意的重复性和再现性。该传感器已成功应用于水样中铜（II）离子的测定。
