Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Iran.
Anal Bioanal Chem. 2019 Nov;411(28):7441-7449. doi: 10.1007/s00216-019-02106-4. Epub 2019 Oct 26.
A novel method combining headspace single-drop microextraction with a paper-based colorimetric assay was developed. Headspace single-drop microextraction using a microdrop containing unmodified gold nanoparticles (AuNPs) as both the extractant and the colorimetric probe was used for the sensitive and selective determination of Se(IV). The method relies on the color change of the microdrop solution caused by the adsorption of in situ-generated hydrogen selenide on the surface of AuNPs. Following extraction, the microdrop was spotted onto cellulose paper, and scanometric-assisted digital image analysis was used for selenium quantification. The analytical variables affecting the method sensitivity, including the drop volume, the concentrations of KBH, HCl, and AuNP solutions, and the extraction time, were studied. Under the optimal conditions, a linear correlation between the colorimetric signal and Se(IV) concentration in the range from 15-100 μg L with a limit of quantification of 12 μg L was achieved. The repeatability of the method was studied by the calculation of intraday and interday precision for the standard solutions at concentrations of 20 and 70 μg L. The batch-to-batch reproducibility of the AuNPs synthesized under the same conditions was also assessed. The relative standard deviations were less than 7%. The method provided satisfactory results for the determination of selenium in real samples.
一种将顶空单滴微萃取与基于纸的比色分析相结合的新方法被开发出来。使用含有未经修饰的金纳米粒子 (AuNPs) 的微滴作为萃取剂和比色探针的顶空单滴微萃取用于灵敏和选择性地测定 Se(IV)。该方法依赖于原位生成的硒化氢在 AuNPs 表面吸附引起的微滴溶液颜色变化。萃取后，将微滴点在纤维素纸上，并使用扫描辅助数字图像分析进行硒定量。研究了影响方法灵敏度的分析变量，包括液滴体积、KBH、HCl 和 AuNP 溶液的浓度以及萃取时间。在最佳条件下，比色信号与 Se(IV)浓度在 15-100 μg L 范围内呈线性相关，检出限为 12 μg L。通过计算浓度为 20 和 70 μg L 的标准溶液的日内和日间精密度来研究该方法的重复性。还评估了在相同条件下合成的 AuNPs 的批间重现性。相对标准偏差小于 7%。该方法为实际样品中硒的测定提供了令人满意的结果。
