The Dependence of Boron Concentration in Diamond Electrode for Ciprofloxacin Electrochemical Sensor Application
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2023-06-08 |
| Journal | Indonesian Journal of Chemistry |
| Authors | Ilmi Nur Indriani Savitri, Prastika Krisma Jiwanti, Ilmanda Zalzabhila Danistya Putri, Irkham Irkham, Yasuaki Einaga |
| Institutions | Airlangga University, Padjadjaran University |
| Citations | 6 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis study successfully engineered and optimized Boron-Doped Diamond (BDD) electrodes for the highly sensitive electrochemical detection of Ciprofloxacin (CIP), a critical fluoroquinolone antibiotic contaminant.
- Material Optimization: The performance of BDD electrodes was critically dependent on boron concentration, with the 1% B/C ratio electrode exhibiting superior electrochemical properties.
- Enhanced Sensitivity: The 1% BDD electrode achieved the highest signal-to-background (S/B) ratio (16.90) and the lowest Limit of Detection (LOD) at 0.17 ”M.
- Regulatory Compliance: This LOD (0.17 ”M) is below the maximum residue limit (MRL) for CIP in milk (0.30 ”M), validating the method for food safety applications after simple sample dilution.
- Reaction Mechanism: Electrochemical oxidation of CIP was confirmed to be a diffusion-controlled, irreversible process across all tested BDD concentrations (R2 > 0.99 for peak current vs. square root of scan rate).
- Robust Performance: The developed Square Wave Voltammetry (SWV) method showed high accuracy (85-110% recovery) and good precision (%RSD < 3.23%) when analyzing CIP in complex real samples (pharmaceuticals, milk, and wastewater).
- Interference Selectivity: The sensor maintained acceptable selectivity against structurally similar quinolone antibiotics (Levofloxacin and Ofloxacin) and common biological interferents (D-Glucose).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Boron Concentration (B/C) Tested | 0.1, 0.5, 1 | % | BDD electrode preparation |
| Diamond Deposition Method | MPCVD | N/A | Microwave Plasma-Assisted CVD |
| Deposition Time | 6 | h | BDD film growth |
| Potential Window (0.1% BDD) | -2.5 to 2.5 | V | Measured in 0.1 M H2SO4 |
| Optimal Supporting Electrolyte | PBS | pH 7 | Phosphate Buffered Saline |
| Raman Peak Shift (1% BDD) | 1215 | cm-1 | Confirms sp3 diamond structure |
| Highest Signal/Background (S/B) | 16.90 | N/A | Achieved by 1% BDD |
| Lowest Limit of Detection (LOD) | 0.17 | ”M | Achieved by 1% BDD |
| Linear Concentration Range | 30-100 | ”M | For CIP detection (SWV) |
| Sensitivity (1% BDD) | 0.379 | ”M/”A | Slope of calibration curve |
| Diffusion Control Correlation (R2) | 0.997 | N/A | 1% BDD (Peak current vs. square root of scan rate) |
| Real Sample Recovery Range | 85-110 | % | Pharmaceuticals, milk, wastewater |
| Reproducibility (%RSD) | 1.46-3.23 | % | Across all BDD electrodes |
Key Methodologies
Section titled âKey Methodologiesâ- BDD Film Fabrication: BDD films with controlled boron concentrations (0.1%, 0.5%, and 1% B/C ratio) were deposited onto silicon wafer (111) substrates using a Microwave Plasma-Assisted Chemical Vapor Deposition (MPCVD) system (Model AX6500X). The deposition time was fixed at 6 hours.
- Structural Characterization: Raman spectroscopy (Acton SP2500, 532 nm excited wavelength) was used to confirm the quality of the BDD films, verifying the presence of sp3-bonded carbon and the absence of sp2 carbon impurities (no peak observed near 1500 cm-1).
- Electrochemical Pretreatment: Prior to sensing, BDD electrodes (0.5 cm diameter) were sonicated and electrochemically pretreated using Cyclic Voltammetry (CV). This involved 40 cycles in 0.1 M H2SO4 over a potential range of -2.5 V to 2.5 V to clean the surface and establish the potential window.
- Sensing Technique: Electrochemical measurements were performed using Square Wave Voltammetry (SWV) in a single-compartment three-electrode cell setup (BDD working electrode, Ag/AgCl reference, Pt mesh counter electrode).
- Optimization Parameters:
- Supporting Electrolyte: 0.1 M Phosphate Buffered Saline (PBS) was used, with pH optimized between 5 and 8. Optimal current response was observed at pH 7.
- Scan Rate: CV was performed at scan rates ranging from 20 to 120 mV/s to confirm the diffusion-controlled nature of the CIP oxidation reaction.
- Analytical Validation: LOD, LOQ, linearity (30-100 ”M), reproducibility (%RSD), and selectivity against Levofloxacin, Ofloxacin, and D-Glucose were determined using SWV.
Commercial Applications
Section titled âCommercial ApplicationsâThe optimized BDD electrochemical sensor technology is highly relevant for industries requiring robust, sensitive, and rapid detection of pharmaceutical contaminants.
- Environmental Monitoring and Water Treatment:
- Deployment of portable sensors for continuous, real-time monitoring of CIP residues in industrial wastewater effluent and surface water bodies, crucial for mitigating long-term environmental antibiotic resistance.
- Food and Agriculture Safety:
- Rapid screening devices for quality assurance in the dairy industry, ensuring antibiotic concentrations (specifically CIP) in milk and dairy products remain below strict regulatory limits (e.g., 0.1 mg L-1 MRL).
- Pharmaceutical Quality Control:
- Fast, low-cost analytical tools for determining CIP concentration and purity in pharmaceutical formulations, serving as an efficient alternative to traditional chromatographic methods (HPLC).
- Advanced Electrode Manufacturing:
- The findings on the relationship between boron doping level and electrochemical performance provide critical data for manufacturers specializing in application-specific BDD electrodes, enabling the production of highly conductive, high-S/B ratio materials for electroanalysis.
- Biomedical and Clinical Analysis:
- Potential use in simplified clinical settings for monitoring antibiotic levels in biological fluids (e.g., urine or plasma), leveraging the high stability and low background current of BDD.
View Original Abstract
This study investigates the effects of boron concentration on boron-doped diamond (BDD) electrodes for electrochemical sensors of ciprofloxacin. The effects of boron concentration, scan rate, and pH of BDD electrodes with boron concentrations of 0.1, 0.5, and 1% were examined to determine the optimal conditions. Furthermore, square wave voltammetry (SWV) in phosphate buffer pH 7 was used to analyze the electrochemical behavior of ciprofloxacin. The results revealed a linear calibration curve in the concentration range of 30-100 ÎŒM with a recovery of 85-110%. Meanwhile, BDD electrode with the highest boron concentration in this experiment (1%) showed a very low limit of detection of 0.17 ÎŒM, meaning that 1% BDD gave a highly sensitive and significant measurement result for the electrochemical sensor of ciprofloxacin. With the results given, this study provides new insights for controlling boron concentrations in diamond electrodes for the electrochemical sensors of quinolone antibiotics.