Colorimetric Response of Dithizone Product and Hexadecyl Trimethyl Ammonium Bromide Modified Gold Nanoparticle Dispersion to 10 Types of Heavy Metal Ions: Understanding the Involved Molecules from Exp

详细信息    查看全文

• 作者：Yumin Leng ; Yonglong ; Li ; An Gong ; Zheyu Shen ; Liang Chen ; Aiguo Wu
• 刊名：Langmuir
• 出版年：2013
• 出版时间：June 25, 2013
• 年：2013
• 卷：29
• 期：25
• 页码：7591-7599
• 全文大小：521K
• 年卷期：v.29,no.25(June 25, 2013)
• ISSN：1520-5827

文摘

A new kind of analytical reagent, hexadecyl trimethyl ammonium bromide (CTAB), and dithizone product-modified gold nanoparticle dispersion, is developed for colorimetric response to 10 types of heavy metal ions (Mⁿ⁺), including Cr(VI), Cr³⁺, Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺. The color change of the modified gold nanoparticle dispersion is instantaneous and distinct for Mn²⁺, Co²⁺, Ni²⁺, Cu²⁺, Zn²⁺, Cd²⁺, Hg²⁺, and Pb²⁺. The color change results from the multiple reasons, such as electronic transitions, cation鈭捪€ interactions, formation of coordination bonds, and Mⁿ⁺-induced aggregation of gold nanoparticles (AuNPs). The different combining capacity of heavy metal ions to modifiers results in the different broadening and red-shifting of the plasmon peak of modified AuNPs. In addition, Cr(VI), Cu²⁺, Co²⁺, Ni²⁺, and Mn²⁺ cause the new UV鈥搗is absorption peaks in the region of 360鈥?60 nm. The interactions between the modifiers and AuNPs, and between the modifiers and Mⁿ⁺, are investigated by using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The results confirm that AuNPs are modified by CTAB and dithizone products through electrostatic interactions and Au鈥揝 bonds, respectively, and the Mⁿ⁺鈥揘 bonds form between Mⁿ⁺ and dithizone products. Furthermore, the experimental and density functional theory calculated IR spectra prove that dithizone reacts with NaOH to produce C₆H₅O^{鈥?/sup> and [SCH₂N₄]2-. The validation of this method is carried out by analysis of heavy metal ions in tap water.}