開發奈米複合材料修飾電極結合電化學分析之有機磷農藥感測器

Abstract

本研究發展出一種極靈敏的電化學感測器來偵測農藥中經常被使用到 的有機磷酸酯化合物。二氧化鋯奈米粒子藉由Nafion 的輔助，能有效固定到修飾有金奈米粒子的氧化銦錫電極上(標記為ZrO2-Nf-AuNP/ITO 電極)。由於二氧化鋯奈米粒子能和含有磷的官能基化合物產生很好的親和性，因此二氧化鋯奈米粒子被使用來當作一種選擇性的吸附劑能有效吸附此類有機磷酸酯類化合物到電極表面上。這裡利用Nafion 表面的多孔材料性質，能有效均一的分散二氧化鋯奈米粒子到電極表面上。金奈米粒子的使用有效提升表面電子傳遞速率，增加基材導電度，對於硝基類的官能機能提供很好的催化能力。本研究利用方波伏安法偵測甲基巴拉松作為代表在偵測有機磷酸酯類化合物上顯示出這樣的電極具備有相當優良的靈敏度及專一選擇性。利用方波伏安法在偵測甲基巴拉松化合物有很好的線性範圍在3nM 到150 nM 之間，偵測極限能達到0.8 nM。且能有效排除一些結構類似但不具有含磷官能基的其他干擾物。利用標準添加法在取樣的水源當中逐 步添加入低、中、高濃度分別為15 nM、45 nM、90 nM，回收率分別在86.6± 8.27％, 88.9 ± 3.67％ and 96.7 ± 10.28 之間，顯示此修飾電極能成功的在真實樣品水源裡偵測到甲基巴拉松化合物。

We have designed an extremely sensitive electrochemical biosensor for organophosphate (OP) pesticides analysis. The zirconia (ZrO2) nanoparticles was immobilized onto gold nanoparticles (AuNP) modified indium tin oxide (ITO) electrode by nafion (Nf) film assisting (labeled as ZrO2-Nf-AuNP/ITO). ZrO2 nanoparticle was used as a selective sorbents for preconcentration of OP pesticidesdue to the strong affinity between ZrO2 nanoparticles and phosphoric group. Nafion was chosen to assist ZrO2 immobilized on the surface of the electrode for better separation due to its porous characteristic. The gold nanoparticles exhibited excellent catalytic activity for the nitro groups, which provided high sensitivity for the electrode. The performance of the electrode using stripping voltammetric shows good sensitivity and selectivity for analyzing methyl parathion as the representative of the organophosphate pesticides. The stripping voltammetric response is highly linear over the methyl parathion range 3-150 nM, with a detection limit of 0.8 nM. In addition, interference studies revealed that structurally resemble compounds without phosphate groups would not interfere with this electrode. The electrode is successfully applied for the determination of methyl parathion in water sample. The recovery values from water sample containing low, middle and high concentration of methyl parathion (15,45 and 90 nM) were 86.6 ± 8.27％, 88.9 ± 3.67％ and 96.7 ± 10.28％,respectively.