Cui Hua, Wang Wei, Duan Chun-Feng, Dong Yong-Ping, Guo Ji-Zhao
Department of Chemistry, University of Science and Technology of China, Hefei, Anhui 230026, P.R. China.
Chemistry. 2007;13(24):6975-84. doi: 10.1002/chem.200700011.
It was found that chloroauric acid (HAuCl(4)) could be directly reduced by the luminescent reagent luminol in aqueous solution to form gold nanoparticles (AuNPs), the size of which depended on the amount of luminol. The morphology and surface state of as-prepared AuNPs were characterized by transmission electron microscopy, UV/visible spectroscopy, X-ray photoelectron spectroscopy, FTIR spectroscopy, and thermogravimetric analysis. All results indicated that residual luminol and its oxidation product 3-aminophthalate coexisted on the surface of AuNPs through the weak covalent interaction between gold and nitrogen atoms in their amino groups. Subsequently, a luminol-capped AuNP-modified electrode was fabricated by the immobilization of AuNPs on a gold electrode by virtue of cysteine molecules and then immersion in a luminol solution. The modified electrode was characterized by cyclic voltammetry, electrochemical impedance spectroscopy, and scanning electron microscopy. The as-prepared modified electrode exhibited an electrochemiluminescence (ECL) response in alkaline aqueous solution under a double-step potential. H2O2 was found to enhance the ECL. On this basis, an ECL sensor for the detection of H2O2 was developed. The method is simple, fast, and reagent free. It is applicable to the determination of H2O2 in the range of 3x10(-7)-1x10(-3) mol L(-1) with a detection limit of 1x10(-7) mol L(-1) (S/N=3).
研究发现，氯金酸（HAuCl₄）在水溶液中可被发光试剂鲁米诺直接还原形成金纳米颗粒（AuNPs），其尺寸取决于鲁米诺的用量。通过透射电子显微镜、紫外/可见光谱、X射线光电子能谱、傅里叶变换红外光谱和热重分析对所制备的AuNPs的形貌和表面状态进行了表征。所有结果表明，残留的鲁米诺及其氧化产物3-氨基邻苯二甲酸通过金与氨基中氮原子之间的弱共价相互作用共存于AuNPs表面。随后，通过半胱氨酸分子将AuNPs固定在金电极上，然后浸入鲁米诺溶液中，制备了鲁米诺包覆的AuNP修饰电极。通过循环伏安法、电化学阻抗谱和扫描电子显微镜对修饰电极进行了表征。所制备的修饰电极在双步电位下在碱性水溶液中表现出电化学发光（ECL）响应。发现H₂O₂可增强ECL。在此基础上，开发了一种用于检测H₂O₂的ECL传感器。该方法简单、快速且无需试剂。适用于测定3×10⁻⁷ - 1×10⁻³ mol L⁻¹范围内的H₂O₂，检测限为1×10⁻⁷ mol L⁻¹（S/N = 3）。
