Universidade Estadual do Sudoeste da Bahia, Programa de Pós-Graduação em Química, Campus de Jequié, Jequié, Bahia, 45206-510, Brazil; Universidade Federal da Bahia, Programa de Pós-Graduação em Química, Campus Universitário de Ondina, Salvador, Bahia, 40170-280, Brazil.
Universidade Estadual do Sudoeste da Bahia, Programa de Pós-Graduação em Química, Campus de Jequié, Jequié, Bahia, 45206-510, Brazil.
Talanta. 2022 Feb 1;238(Pt 2):123038. doi: 10.1016/j.talanta.2021.123038. Epub 2021 Nov 8.
An on-line system employing switchable-hydrophilicity solvent-based liquid-phase microextraction (SHS-LPME) is described in this work. The method is based on the preconcentration of the species formed between cobalt and the reagent 1-nitroso-2-naphthol (NN), with subsequent detection by digital image colorimetry. The system's operation begins with the on-line mixture of sample, switchable solvent, and an alkaline agent in a reaction coil. Then the mixture is transported to an extraction chamber. The introduction of a proton donor leads to the passage of the solvent to its hydrophobic form, which allows phase separation. The rich phase is then directed to a glass tube, where detection is performed. Octanoic acid, sodium carbonate, and sulfuric acid were used as the extraction solvent, the alkaline agent, and the proton donor, respectively. Under optimized conditions, the method presented a detection limit of 0.8 μg L and an enrichment factor of 41. The precision obtained was 4.8% (20 μg L). The accuracy of the method was tested by the analysis of Tomato Leaves certified reference material (NIST 1573a). The method was applied to the determination of cobalt in food, dietary supplements, and water samples. The method is presented as a green alternative and very accessible to the determination of cobalt in the analyzed samples.
本文介绍了一种采用可切换亲水性溶剂液相微萃取（SHS-LPME）的在线系统。该方法基于钴与试剂 1-亚硝基-2-萘酚（NN）形成的物种的预浓缩，随后通过数字图像比色法进行检测。该系统的操作始于在线混合样品、可切换溶剂和碱性试剂在反应盘管中。然后将混合物输送到萃取室。引入质子供体导致溶剂向疏水性形式转变，从而实现相分离。富含溶剂的相随后被引导到玻璃管中进行检测。辛酸、碳酸钠和硫酸分别用作萃取溶剂、碱性试剂和质子供体。在优化条件下，该方法的检测限为 0.8μg/L，富集因子为 41。在 20μg/L 时获得的精密度为 4.8%。通过对 Tomato Leaves 认证参考物质（NIST 1573a）的分析来测试方法的准确性。该方法已应用于食品、膳食补充剂和水样中钴的测定。该方法是一种绿色替代方法，非常适合分析样品中钴的测定。
