Title Page
ABSTRACT
Contents
I. INTRODUCTION 10
1. Some sensing methods for detecting antibiotics 10
1.1. Biosensors 10
1.2. Electrochemical sensors 11
1.3. Some improvements in electrochemical sensing 16
II. EXPERIMENT METHOD 18
1. ZnCo₂O₄ synthesis 18
1.1. Material 18
1.2. Synthesis of ZnCo₂O₄ 18
2. Preparation of ZnCo₂O₄ ink 18
3. Electrode modification 18
III. RESULT AND DISCUSSION 19
1. Structure and morphology characteristics 19
2. Electrochemical properties 21
IV. Conclusion 34
References 36
Table 1. Peak currents and calculated electrochemical active surface areas of bare electrode and electrodes modified with ZCO2, ZCO4, ZCO6 and ZCO8 22
Table 2. Detection of CAP in milk sample 33
Table 3. Comparing detecting performance of CAP of some materials 35
Figure 1. Structure of biosensors 10
Figure 2. Schematic of electrochemical sensors 12
Figure 3. General pattern of potential vs time in cyclic voltammetry 13
Figure 4. Voltammogram of K3Fe(CN)6/K4Fe(CN)6[이미지참조] 13
Figure 5. Potential steps in DPV method 15
Figure 6. DPV curves with different concentrations of analyte 15
Figure 7. XRD patterns of ZnCo₂O₄ and ZnCo₂O₄ annealed at 200 □C, 400 □C, 600 □C, 800 □[원문불량;p.18] 19
Figure 8. SEM images of ZnCo₂O₄ (a) and ZnCo₂O₄ annealed at 200 □C (b), 400 □C (c), 600 □C (d) and 800 □C (e)[원문불량;p.19] 20
Figure 9. CVs of sensors in K3Fe(CN)6/KCl solution[이미지참조] 21
Figure 10. CV response of sensor modified with ZCO6 in the solution of PBS and PBS/CAP 23
Figure 11. CV curves of bare SPE and SPEs modified with ZCO2, ZCO4, ZCO6, ZCO8 in PBS solution containing CAP 24
Figure 12. Peak current at E=-0.78 V of bare SPE and SPEs modified with ZCO2, ZCO4, ZCO6, ZCO8 24
Figure 13. CV curves of SPE/ZCO6 with scan rate ranging from 30-200 m.V.s-1 25
Figure 14. Calibration line of I vs v1/2 at 3 redox peaks 26
Figure 15. Peak potential with scanrate varying from 20-200 mVs 27
Figure 16. Proposed mechanism of redox reactions of CAP 28
Figure 17. DPV curves of ZCO6/SPE in PBS/CAP with various values of pH 28
Figure 18. Potential and current of peak R of ZCO6/SPE in PBS/CAP with various pH values 29
Figure 19. DPV curve of ZCO6/SPE with concentration of CAP ranging from 1-300 μM and calibration line (inserted picture) 30
Figure 20. Peak current without and with the presence of some types of substances 31
Figure 21. Current response of 5 different electrodes modified with ZCO6 31
Figure 22. Peak current measured after 30 days in atmosphere 32