製備磁性分子印跡聚合物以應用於電化學測定三聚氰胺

Preparation of Magnetic Molecularly Imprinted Polymers for Electrochemical Determination of Melamine

何韋竺(Wei-Chu Ho)

指導教授 ： 鄭淑華

國立暨南國際大學/科技學院/應用化學學系/碩士(2019年)

https://doi.org/10.6837/ncnu201900135

摘要

衛生福利部食品藥物管理署規定於食品中不得檢出三聚氰胺，然而現今檢測三聚氰胺之分析技術以貴重儀器為主，如HPLC、MS、LC等。電化學偵測技術具有低成本、方便檢測的優點，以磁性分子印跡聚合物作為修飾電極進行三聚氰胺的定量分析，可望發展成具有良好的靈敏度與選擇性之電化學感測器。
本研究是以化學合成方式製備磁性分子印跡聚合物 (magnetic molecularly imprinted polymer, MMIP) ，並將之配置成溶液滴在網版印刷碳電極 (screen-printed carbon electrode, SPCE)上，針對三聚氰胺 (melamine)進行定量分析。合成MMIP可分成兩步驟，第一步為合成官能基化之單體，先以多壁奈米碳管、氯化鐵和氯化亞鐵之混合溶液，利用共沉澱法製備多壁奈米碳管與磁性奈米氧化鐵顆粒的複合材料。接著，再進行矽烷化，包覆上一層矽薄膜並帶有氫氧根(-OH)，再和 3-(Trimethoxysilyl)- propyl methacrylate (MPS)進行反應，讓磁性奈米顆粒官能基化，使其末端帶碳碳雙鍵 (C=C)。第二步為聚合反應，將官能基化後的磁性奈米顆粒，與丙烯醯胺(acrylamide)、亞甲基雙丙烯醯胺(N,N’-methylenebisacrylamide)、三聚氰胺 (melamine)、偶氮二異丁腈(AIBN)進行聚合反應，形成MMIP-melamine，接著以有機溶劑(甲醇加醋酸)除去三聚氰胺，形成最終產物MMIP。將MMIP配置成溶液，塗附在網版印刷碳電極，在 ferricyanide溶液中進行電化學SWV之活性測試。將SPCE/MMIP浸泡 1分鐘後，可發現ferricyanide的還原訊號會隨著ME濃度增加而逐漸下降，在0.1 – 500 μM有一線性關係，R2=0.96654，偵測極限為0.048 μM。之後可應用在真實樣品中，如牛奶、奶粉等高蛋白含量乳製品。

關鍵字

網版印刷碳電極 ； 羧酸化奈米碳管 ； 磁性分子印跡聚合物 ； 三聚氰胺

並列摘要

Taiwan Food and Drug Administration stipulates that melamine should not be detected in human food. Today, the analytical technology for detecting　melamine includes modern instruments such as HPLC, MS and LC. However, these instruments are expensive for routine analysis. We intend to develop a low-cost, easy-to-detect electrochemical detection method based on a modified electrode, which is expected to achieve good sensitivity and selectivity for melamine determination.
　　In this study, magnetic molecularly imprinted polymers (MMIP) was prepared by chemical synthesis, and then used to modify screen-printed carbon electrode for quantitative analysis of melamine. The synthesis procedures can be divided into two steps. The first step is to synthesize the functional monomer and second step is thermal polymerization to form MMIP-melamine. First, a composite of multi-walled carbon nanotube (MWCNT) and magnetic nano-iron oxide particles was prepared by co-precipitation method, using a mixed solution of MWCNT, ferric chloride and ferrous chloride .Then, the composite surface was coated a layer of silica film with exposed terminal hydroxide (-OH) groups, which was further reacted with 3-(Trimethoxysilyl) - propyl methacrylate (MPS) to functionalize with carbon-carbon double bond (C=C). Second, thermal polymerization was proceeded using the functionalized material, acrylamide, N,N'-methylenebisacrylamide, melamine, and azobisisobutyronitrile (AIBN) to form MMIP-melamine. The bound melamine was removed with an organic mixed solvent (methanol and acetic acid) to give the final product MMIP. The MMIP-modified screen-printed carbon electrode (SPCE/MMIP) was subjected to an electrochemical SWV activity test in a ferricyanide solution.It was found that the reduction current of ferricyanide gradually decreased with the increase of melamine concentration in logarithmic scale. There was a linear relationship between 0.1 μM and 500 μM, (R2=0.9922), and the limit of detection (S/N = 3) was 0.048 μM. The developed assay can then be applied to real samples, such as high-protein dairy products, infant milk and milk powder.

並列關鍵字

screen-printed carbon electrode ； carboxylic acid functionalized multi-walled carbon nanotube ； magnetic molecularly imprinted polymers ； melamine

參考文獻

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