二甲酚橙鈉鹽/二氧化鈦薄膜固態感測器於銅、鋅離子(Cu2+、Zn2+)的偵測與分子動態模擬研究銅、鋅離子和二甲酚橙離子的錯合結構

Abstract

In this research,the role of xylenol orange(XO) employed as a sensor molecule for Cu2+, Zn2+ ions was investigated. In XO aqueous solution,the absorption of visible light was significantly affected by the pH value. Therefore,we use TiO2 films as a buffer to avoid pH effects interfering the metal ion sensing.XO-TiO2 films were used to detect Cu2+ ions in the pH range of 3-5.5 and Zn2+ ions in the pH range of 4-5 with good buffering action and stable detection capabilities. The calibration curve plot of different Cu2+,Zn2+ ion concentration sensed by the XO-TiO2 films to ΔF(R) with a similar trend.It indicating that XO-TiO2 films have fixed detection mechanism for sensing metal ions and could be judged by the color change of the films with naked eyes.The naked-eye detection limit of XO-TiO2 films for the Cu2+ ion was 2.5×10-5 M(1.59 ppm) and for Zn2+ ion was 4×10-5 M(2.615 ppm).The detection limit of spectrum for Cu2+ was 7.5x10-6 M(0.476 ppm) and for Zn2+ was 1x10-5 M(0.654 ppm). Molecular dynamics simulations were employed to study the coordinated structure of Cu2+, Zn2+ ions in the XO aqueous solution. According to the structure in the simulation system,we analyzed the complex structure of XO molecules binding to Cu2+, Zn2+ ions, and we used the method of pair correlation function to reconfirm. Based on the result, we found that the Cu2+, Zn2+ ions might coordinated with the carboxylate group and sulfonic acid group of the XO molecule.