Voltammetric determination of anti-malarial drug amodiaquine at a boron-doped diamond electrode surface in an anionic surfactant media
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-12-30 |
| Journal | Macedonian Journal of Chemistry and Chemical Engineering |
| Authors | Sara Kurdo Kamal, Yavuz Yardım |
| Institutions | Van YĂŒzĂŒncĂŒ Yıl Ăniversitesi |
| Citations | 3 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis study details the development of a highly sensitive and rapid voltammetric method for determining the anti-malarial drug Amodiaquine (ADQ) using a Boron-Doped Diamond (BDD) electrode.
- Core Technology: Square-Wave Adsorptive Stripping Voltammetry (SW-AdSV) was employed on a pretreated BDD electrode, leveraging its stability and wide potential window.
- Performance Enhancement: The addition of the anionic surfactant Sodium Dodecyl Sulfate (SDS) significantly enhanced the ADQ oxidation signal, resulting in peak currents approximately 3.0 times higher than in surfactant-free solutions.
- High Sensitivity: The method achieved an excellent Limit of Detection (LOD) of 6.5·10-8 mol l-1 (0.03 ”g ml-1), demonstrating superior sensitivity compared to previously reported electrochemical ADQ sensors.
- Reaction Mechanism: The electro-oxidation of ADQ was determined to be a quasi-reversible, diffusion-controlled process, involving a two-electron, two-proton transfer (Scheme 1).
- Reproducibility: The BDD electrode showed good stability and precision, with relative standard deviation (RSD) values of 5.39% (intra-day) and 6.26% (inter-day).
- Practical Application: The method was successfully validated for the direct determination of ADQ in tap water samples, yielding satisfactory recovery percentages (92.4% to 108.0%).
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Working Electrode Material | Boron-Doped Diamond (BDD) | N/A | Boron content: 1000 ppm |
| Electrode Diameter | 3 | mm | Commercial BDD electrode |
| Supporting Electrolyte | Britton-Robinson (BR) Buffer | N/A | Optimized pH 8.0 |
| Surfactant (SDS) Concentration | 2.0·10-4 | mol l-1 | Optimized for maximum signal |
| Oxidation Peak Potential (Ep) | +0.34 | V (vs. Ag/AgCl) | Under optimized SW-AdSV conditions |
| Accumulation Time (tacc) | 30 | s | Applied at open-circuit potential |
| Stirring Rate (Accumulation) | 500 | rpm | Used during accumulation phase |
| Linear Concentration Range | 2.2·10-7 to 4.3·10-5 | mol l-1 | Calibration range for ADQ |
| Limit of Detection (LOD) | 6.5·10-8 | mol l-1 | Calculated as 3.3 s/m |
| Square-Wave Frequency (f) | 50 | Hz | Optimized SWV parameter |
| Pulse Amplitude (ÎEsw) | 50 | mV | Optimized SWV parameter |
| Step Potential (ÎEs) | 12 | mV | Optimized SWV parameter |
| Intra-day Reproducibility (RSD) | 5.39 | % | For 0.1 ”g ml-1 ADQ (10 replicates) |
| Inter-day Reproducibility (RSD) | 6.26 | % | For 0.1 ”g ml-1 ADQ (3 days) |
| CV Anodic Peak (No SDS) | +0.48 | V (vs. Ag/AgCl) | Quasi-reversible oxidation |
Key Methodologies
Section titled âKey MethodologiesâThe electrochemical determination of ADQ utilized a three-electrode cell configuration (BDD working, Pt wire auxiliary, Ag/AgCl reference) at 25 ± 1 °C.
-
Electrode Pretreatment (Activation):
- Anodic activation: +1.8 V for 180 s in 0.5 mol l-1 H2SO4.
- Cathodic activation: -1.8 V for 180 s in 0.5 mol l-1 H2SO4.
- Mechanical cleaning: Gentle rubbing with a damp polishing cloth between measurements.
-
Electrolyte and Surfactant Selection:
- pH Optimization: Cyclic Voltammetry (CV) and Square-Wave Voltammetry (SWV) determined the optimal supporting electrolyte to be BR buffer at pH 8.0.
- Surfactant Testing: Anionic (SDS), cationic (CTAB), and non-ionic (Tween 20) surfactants were tested. SDS provided the highest peak current.
- SDS Optimization: Optimal SDS concentration was fixed at 2.0·10-4 mol l-1.
-
SW-AdSV Optimization Protocol:
- Accumulation Potential (Eacc): Open-circuit condition was selected, as varying the potential from +0.1 V to +0.3 V showed no effect on the anodic peak current.
- Accumulation Time (tacc): Optimized to 30 s while stirring at 500 rpm.
- Stripping Scan: Anodic scanning applied from 0.0 V to +1.3 V.
- Optimized SW Parameters: Frequency (f) = 50 Hz, Pulse Amplitude (ÎEsw) = 50 mV, Step Potential (ÎEs) = 12 mV.
-
Sample Analysis:
- Tap water samples were analyzed without further pretreatment.
- Quantification was performed using the standard addition method (six additions).
Commercial Applications
Section titled âCommercial ApplicationsâThe robust, sensitive, and rapid nature of this BDD-based electrochemical method makes it highly relevant for applications requiring trace analysis of pharmaceuticals in complex matrices.
- Environmental Monitoring and Water Safety:
- Trace determination of pharmaceutical contaminants (like ADQ) in drinking water, tap water, and wastewater effluent, leveraging the low LOD (0.03 ”g ml-1).
- Pharmaceutical Quality Control (QC):
- Rapid, low-cost analysis platform for quantifying ADQ in raw materials or finished drug formulations, offering an alternative to expensive and time-consuming HPLC/LC-MS methods.
- Electrochemical Sensor Technology:
- Development of stable, reusable electrochemical sensors for redox-active organic compounds, utilizing the BDD electrodeâs chemical inertness and wide operational window.
- Clinical and Bioanalytical Screening:
- While tested in water, the high sensitivity suggests potential for developing simplified screening methods for ADQ and its metabolites in biological fluids (e.g., plasma or urine), provided matrix interference is managed.
View Original Abstract
In this study, the electrochemical determination of the amodiaquine (ADQ) drug was evaluated using an electrochemically pretreated boron-doped diamond (BDD) electrode due to the enhanced surface activity. The cyclic voltammogram results of ADQ were given as single reversible and diffusion-controlled peaks at +0.48 V for the oxidation peak and +0.05 V for the reduction peak (vs. Ag/AgCl) in Britton-Robinson (BR) buffer at pH 8.0. The peak potential and current signals of ADQ were evaluated at the surface of the BDD electrode using instrumental parameters to develop a simple method for ADQ detection. Also, the effect of an anionic surfactant, sodium dodecyl sulfate (SDS), on the adsorption applicability of the BDD electrode significantly increased the stripping voltammetric determination of ADQ. Under the optimal conditions chosen and employing square-wave adsorptive stripping voltammetry at the BDD electrode, ADQ was determined at + 0.34 V (vs. Ag/AgCl) at the open-circuit condition in BR buffer at pH 8.0 in the presence of 2·10-4 mol l-1 SDS. Furthermore, analytical parameters showed the linear relationship for ADQ determination in the concentration range of 0.1-20.0 Όg ml-1 (2.2·10-7 - 4.3·10-5 mol l-1), with a detection limit of 0.03 Όg ml-1 (6.5·10-8 mol l-1). The proposed approach can be applied to determine ADQ in water samples.