The condensation product of 5-methoxy-salicylaldehyde with hydrazine hydrate (referred to below as compound 1) was used as a ligand in a cellulose acetate electrospun nanofibrous mat to determine copper ions in aqueous solutions. The electrospun nanofibrous mats, based on cellulose acetate mixed with compound 1, were constructed using an electrospinning method and had a diameter of 260 nm. The sensing nanofibrous mat exhibited a sensitive and selective response for Cu(II) ions over a linear concentration range of 1-30 µM in a 0.1 M HEPES buffer (pH 7.4) using a colorimeter. The detection limit of the method was 1.04 µM lower than the maximum level of Cu(II) in drinking water (16 µM, as determined by the US Environmental Protection Agency). Additionally, it exhibited high selectivity for Cu(II) ions over 13 other cations. The sensing nanofibrous mat was fully reversible for ethylenediamine tetraacetic acid treatment cycles. Preliminary results indicated the sensitivity and selectivity of the nanofibrous mat for detecting Cu(II) ions by naked-eye detection from yellow to orange. The reaction product of compound 1 and the Cu(II) ion was studied using X-ray absorption spectroscopy. The Cu-coordination number was approximately 5.023 ± 1.42, and the Cu–N distance (R) was 1.986 Å. The nanofibrous mat demonstrated a convenient and straightforward Cu(II) ion-detection technique in both wastewater and water environments.

中文翻译：

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电纺纳米纤维垫与 5-甲氧基水杨醛吖嗪混合的 Cu(II) 比色化学传感器

5-甲氧基水杨醛与水合肼的缩合产物（以下称为化合物1）用作醋酸纤维素电纺纳米纤维垫中的配体，以测定水溶液中的铜离子。基于醋酸纤维素与化合物1混合的电纺纳米纤维垫，使用静电纺丝方法构造，直径为 260 nm。传感纳米纤维垫在 0.1 M HEPES 缓冲液 (pH 7.4) 中使用比色计在 1-30 µM 的线性浓度范围内表现出对 Cu(II) 离子的灵敏和选择性响应。该方法的检测限比饮用水中 Cu(II) 的最高水平（16 µM，由美国环境保护署确定）低 1.04 µM。此外，它对 Cu(II) 离子的选择性高于其他 13 种阳离子。传感纳米纤维垫对于乙二胺四乙酸处理循环是完全可逆的。初步结果表明纳米纤维垫对通过从黄色到橙色的肉眼检测来检测 Cu(II) 离子的灵敏度和选择性。化合物1的反应产物并使用X射线吸收光谱研究了Cu（II）离子。Cu 配位数约为 5.023 ± 1.42，Cu-N 距离 (R) 为 1.986 Å。纳米纤维垫在废水和水环境中展示了一种方便且直接的 Cu(II) 离子检测技术。