Faculdade de Química, Instituto de Ciências Exatas, Universidade Federal do Sul e Sudeste do Pará, Folha 17, Quadra 04, Lote Especial, Marabá, PA, 68505-080, Brazil.
Departamento de Química, Universidade Federal de São Carlos, Rodovia Washington Luis, CP 676, São Carlos, SP, 13565-905, Brazil.
Mikrochim Acta. 2019 Jul 10;186(8):525. doi: 10.1007/s00604-019-3645-9.
An electroanalytical method for determining dienestrol (DNL) in bovine urine samples is described. A glassy carbon electrode (GCE) modified with silver nanoparticles and functionalized multi-walled carbon nanotubes was used as working sensor. The modified GCE displays substantial analytical improvements including an amplified signal, fast electron transfer kinetics, and resistance to fouling. The irreversible oxidation signal of DNL is pH-dependent. Best reactivity is found at pH 3.0, where a typical anodic peak is recorded at 0.8 V (vs. Ag/AgCl). Square-wave voltammetry revealed a 8.4 nM detection limit (1.9 μg L), good repeatability and reproducibility (RSDs <5.0%), and good accuracy (93.2-99.4% recovery from spiked samples). The modified electrode is highly stable even in the presence of ions (Na and K), urea and uric acid. The electrochemical sensor fulfills all requisites to be used as forensic device in surveillance of illegal livestock practices. Graphical abstract Schematic presentation of the construction of a glassy carbon electrode modified with silver nanoparticles and functionalized multi-walled carbon nanotubes. This sensor exhibited a remarkable performance for voltammetric detection of the illicit growth promoter dienestrol in animal urine.
一种用于测定牛尿液中双烯雌酚（DNL）的电化学分析方法。采用载银纳米粒子和功能化多壁碳纳米管的玻碳电极（GCE）作为工作传感器。修饰后的 GCE 显示出显著的分析改进，包括放大信号、快速电子转移动力学和抗污染能力。DNL 的不可逆氧化信号与 pH 值有关。在 pH 3.0 时具有最佳反应性，在此条件下可在 0.8 V（相对于 Ag/AgCl）处记录到典型的阳极峰。方波伏安法显示出 8.4 nM 的检测限（1.9 μg L）、良好的重复性和重现性（RSDs <5.0%）以及良好的准确性（从加标样品中回收率为 93.2-99.4%）。即使存在离子（Na 和 K）、尿素和尿酸，修饰后的电极也非常稳定。电化学传感器完全符合作为非法牲畜养殖监测的法医设备的要求。 示意图展示了用载银纳米粒子和功能化多壁碳纳米管修饰的玻碳电极的构建。该传感器在动物尿液中非法生长促进剂双烯雌酚的伏安检测中表现出出色的性能。
