化學需氧量(chemical oxygen demand, COD)是用來檢測水中有機污染物含量以及水質監測的重要參數之一。為了減少傳統分析方法所帶來的廢液及有害物，並且減少分析上的誤差，本研究製備去官能基化TiO2/ SWCNTs修飾玻璃碳電極進行COD之伏安法分析。經由表面物化特性以及電流反應強度分析，去官能基後的複合材料表面並不會受到破壞且仍具有催化效果，最後選定以高溫300℃處理的TiO2/ SWCNTs為修飾電極。藉由模擬水樣分析結果顯示，去除TiO2/ SWCNTs表面官能基後，修飾電極確實有較佳的穩定度以及準確度，電流值與COD濃度也有良好的線性關係，並且可量測至0.1 mg/L。在進行多次實場廢水分析結果顯示，對於處理過的或是組成較單純的廢水，LSV法與COD標準方法所得到的變化趨勢相近。;Chemical oxygen demand (COD) is usually monitored because it is one of the important water qualities, which indicates the degree of pollution by organic compounds. To reduce the error in analysis and to limit the consumption of toxic chemicals in standard COD analysis, GCE electrodes were modified by defunctionalized TiO2/ SWCNTs composite and used in COD measurements via voltammetry. The surface physical and chemical properties of TiO2/ SWCNTs composite have been investigated. It was found that the TiO2/ SWCNTs composite treated at 300℃ has the least amount of functional groups and the best electrical property. It was also found that by defunctionalizaion of TiO2/ SWCNTs has improved the stability and the sensitivity of linear scanning voltammetry (LSV). Good correlation between oxidation peak current and COD concentration of modeled water and a low detection limit to 0.1 mg/L were achieved. The analysis of real wastewater samples was carried out by both the LSV and the standard dichromate method. It is found that COD values determined via LSV and standard dichromate method had similar results when the wastewater was treated.