USB驅動型迷你恆電位儀之開發與鄰苯二甲醛消毒劑之檢測

Abstract

本研究採用具有高輸入阻抗、低輸入偏壓電流與低輸入補償電壓等特性之運算放法器（OPA2336P，Texas Instruments），搭配USB供電的DAQ（NI 6008/6009，National Instruments）與LabVIEWTM撰寫的圖形化使用者介面，組裝一台平行輸入自動換檔並且便於攜帶之小型恆電位儀，可應用於實驗室外的現場檢測並且與商用實驗室泛用型儀器（AutolabTM，Eco Chemie）相比所得到之檢測結果幾乎相同。本研究所提出之恆電位儀操作電位的範圍約從-1.3 V到1.1 V，最佳量測的解析度可到100 pA。以本研究所提出之恆電位儀搭配流動式注射系統，對鄰苯二甲醛濃度做初步的的濃度檢測，所量測到的氧化電流大小在0.2%-0.65%（w/v）範圍內呈線性相關（R2 = 0.9911），且變異係數小於5%，靈敏度為0.18 μA/cm2 mM，可應用於評估消毒內視鏡常用之鄰苯二甲醛最低有效濃度（Minimum effective concentration, MEC）。

An auto ranging mini-potentiostat was constructed by parallel reading architecture and using operational amplifiers (OPA2336P, Texas Instruments) with high input impedance, low input bias current and low input offset voltage. After implementing with a USB-powered DAQ (NI 6008/6009, National Instruments) and LabVIEWTM based graphical user interface, the portable electrochemical device can be used for on-site analysis with a performance comparable to a commercialized laboratory machine (AutolabTM, Eco Chemie). The operating voltage ranges from -1.3 V to 1.1 V and the resolution can reach 100 pA level. The mini-potentiostat was served as the amperometric detector of a conventional flow injection analysis system for measuring o-phthalaldehyde concentration. The current outputs (the peak heights of FIAgram) are reproducible (CV < 5%) and showed good linearity (R2 = 0.9911) in the range of 0.2%-0.5% (w/v), which can be used to evaluate the antiseptic efficiency (minimum effective concentration of o-phthalaldehyde) of the disinfectant used for cleaning endoscope. The sensitivity is 0.18 μA/cm2 mM.