以含銀離子醋酸纖維薄膜修飾石英晶體微天平之乙烯感測器

Abstract

本研究建立一個乙烯濃度量測之石英晶體微天平(QCM)氣相濃度分析系統，檢測原理係由於乙烯能與銀離子結合形成強度較強之配位鍵，並結合QCM對其金電極表面質量變化極為靈敏之特性，將AgBF4與醋酸纖維(CA)溶於THF中，將溶液以噴槍噴灑的方式對QCM之金電極表面修飾，以流量控制器調整感測槽中乙烯的濃度，當電極表面因乙烯吸附而產生質量的變化，藉由震盪電路以及計頻器將晶體之共振頻率變化擷取成訊號輸出。文中探討氣體流量、氣體體積、銀離子與CA的質量比、表面修飾量等系統參數的最佳化，並建立QCM表面修飾方法以及檢驗標準。本系統對乙烯濃度之檢測範圍為104 - 105ppm，R2值為0.999，平均響應時間為40秒。藉由金電極表面修飾量以及銀離子比例的最佳化，乙烯濃度之檢測範圍可望滿足農業應用的需求。

A study of quartz crystal microbalance (QCM) modified by a silver ion (Ag+)-coordinated cellulose acetate (CA) membrane for ethylene (C2H4) monitoring is presented in this paper. Silver tetrafluoroborate (AgBF4) and cellulose acetate were dissolved in tetrahydrofuran (THF) and were spun on the surface of QCM to form the sensing membrane. Real-time detection of ethylene was carried out using the oscillator circuit and universal counter is used for data acquisition. A series of membranes with various weight percentage of AgBF4 to cellulose were fabricated and the sensitivity to ethylene was investigated. The linear dynamic range was 104 - 105ppm and the average response time was 40s. The limit of detection (LOD) is expected to be around 1000ppm, which is in the range for agricultural use.