| Summary: | 碩士 === 國立中興大學 === 化學系所 === 106 === In this study, the AuCu3 alloy film was directly formed and deposited on screen-printed carbon electrode (SPCE) by chemical vapor sputtering technique. The thesis can be divided into four parts: first, the quartz plate was used as the substrate and sputtering gold, nickel, and copper metal layers which simulated the sequence of the barrel-plated gold electrode (AuBPE). We found that quartz plate electrode before annealing shows a redox peak of AuCu3 at around 0.2 V (vs. Ag/AgCl) and the electrochemical oxidation of glucose was successfully obtained. In the second part, the electrochemical characteristics in various amounts of gold, nickel, and copper on different substrates including bare-SPCE and gold electrode were investigated. The optimized composition of AuCu3 electrode is (Au30Cu5)-SPCE with an excellent electrocatalytic activity for oxidation of glucose in pH 7 PBS. Chronoamperometric measurement allows observation of the electrochemical oxidation of glucose in neutral solution at 0.3 V with a linear range 100 μM—10 mM (r2 = 0.9894) in the calibration plot. We use SEM, EDS methods to confirm the physical properties of the AuCu3 film. In the third part, the electrocatalytic activity of as-prepared AuCu3 electrodes was discussed. We use the resulting AuCu3 films to detect formaldehyde、acetaldehyde and alcohols. We found that sensitivity of the electrode for aldehydes is significantly different from that of alcohols, resulting in excellent selectivity for aldehydes. It displays that selective detection of 2 mM formaldehyde in the presence of 2 mM methanol was achieved with linearity in the range of 50 μM to 15 mM and a regression coefficient of 0.9939. The detection limit was calculated as 8.45 μM (S/N = 3). Selective detection of 500 μM acetaldehyde in the presence of 5 mM ethanol was achieved with linearity in the range of 300 μM to 1.5 mM and a regression coefficient of 0.9946. The detection and quantification limits were calculated as 44.10 μM and 147.00 μM, respectively. In the fourth part, we tried some methods to increase sensitivity and selectivity of the electrode for aldehydes. We found that sensitivity of the as-prepared electrodes can be enhanced about 20 % by SPCE ultrasonic polished pretreatment. We also found that after activation of the electrode with 0.1 M NaOH solution, it can increase selectivity of the aldehydes detection. This is a breakthrough for the detection of acetaldehyde in high-concentration alcohol solutions. Low cost and simple manufacturing procedure allow the proposed aldehydes sensor to be applied as disposable devices.
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