The Preparation of Functional Materials Modified Screen-printed Carbon Electrodes and Their Application in Food Safety and Drug Assay

• Main Authors: Su, Wanyu, 蘇婉瑜
• Other Authors: Cheng, Shuhua
• Format: Others
• Language: zh-TW
• Published: 2013
• Online Access: http://ndltd.ncl.edu.tw/handle/79891959438304229842

博士 === 國立暨南國際大學 === 應用化學系 === 101 === In the study, we developed three kinds of electrochemical sensors for 4-acetamidophenol (ACAP), aminophenol(AP) isomers and nitrite, respectively. First, the electrocatalytic oxidation of ACAP at electrochemical pretreatment screen-printed electrode (SPCE*) modified with electrogenerated poly(3,4-ethylenedioxythiophene) (PEDOT) film was studied. Cyclic voltammetric studies show that the SPCE*/PEDOT electrode lowers overpotentials and improves electrochemical behavior of acetaminophen (ACAP) in aqueous buffer solutions, compared to the bare SPCE. Excellent analytical features are achieved, including high sensitivity, low detection limit (0.16 μM) and satisfactory dynamic range (0.5-600 μM), by flow-injection amperometry (FIA) under optimized conditions. The proposed methods obtain satisfactory results in detection of acetaminophen in two commercial tablets. Second, the disposable, electrochemically pretreated screen-printed carbon electrodes (SPCE*) can be employed for the simultaneous determination of aminophenol (AP) isomers in aqueous buffer solution. In sharp contrast to untreated SPCE, voltammetric studies indicate that the oxidation peak potential of each analyte in an aminophenol isomer mixture may be separated at SPCE*. The individual oxidation peak currents are greatly increased by first-order derivative techniques. The derivative oxidation peak currents is proportional to the concentration of isomer over the range from 0.2 to 100 μM for 2-aminophenol (2AP), from 3.0 to 200 μM for 3-aminophenol (3AP), and from 0.2 to 200 μM for 4-aminophenol (4AP), with detection limits of 0.07, 0.16 and 0.05 μM, respectively. The proposed methods have excellent analytical characteristics that include ease of handling, high sensitivity, wide linear dynamic range and low detection limits. The assay was applied to the simultaneous determination of aminophenol isomers in river water with good recovery results. In the third part, we provided an easy way to fabricate a composite film-modified electrode, and used as an electrochemical nitrite sensor. A functionalized ionic liquid, 1-butyl-3-methylimidazolium ferricyanide (BMIMFC) has been synthesized and modified onto a screen-printed carbon electrode (SPCE) by deposition methods. Poly(3-(aminopropyl)trimethoxysilane, APTMOS) sol-gel (SG) is then used as the second modified layer. The modified electrodes exhibit a very stable redox couple, and its redox potential is pH-dependent in acid solution. The attractive electrocatalytic activity for the reduction of nitrite is achieved in strongly acidic solutions. As an amperometric nitrite sensor, the modified electrode shows a wide linear range (20-510 μM), a suitable sensitivity (0.0040 μA/μM) and a low detection limit (1.3 μM, S/N = 3). Unlike previous reports on the electrocatalytic reduction of nitrite, the present detection assays indicate insignificant interference from dissolved oxygen and common salts, promising the convenient operation of the nitrite sensor.