Electroanalytical Analysis of Guaifenesin from Pharmaceuticals on Boron Doped Diamond Electrode
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2022-10-19 |
| Journal | Turkish Journal of Analytical Chemistry |
| Authors | Fatma AÄın, Gökçe ĂztĂŒrk, Dilek Kul |
| Institutions | Karadeniz Technical University |
| Citations | 1 |
| Analysis | Full AI Review Included |
Executive Summary
Section titled âExecutive SummaryâThis study successfully developed and validated highly sensitive, rapid, and cost-effective voltammetric methods for the electroanalytical determination of Guaifenesin (GFN) using a bare Boron Doped Diamond Electrode (BDDE).
- High Sensitivity Quantification: Differential Pulse Voltammetry (DPV) and Square Wave Voltammetry (SWV) techniques achieved ultra-low detection limits for GFN: 1.47 nM (DPV) and 2.92 nM (SWV).
- Robust Electrode Material: The BDDE was utilized unmodified, leveraging its wide potential window, low background current, and high electrochemical stability in both acidic and alkaline media.
- Reaction Mechanism: Cyclic Voltammetry (CV) confirmed that the electro-oxidation of GFN on the BDDE surface is an irreversible, diffusion-controlled process.
- Optimal Conditions: The highest sensitivity was achieved using a pH 3.5 Acetate Buffer (AB) solution as the supporting electrolyte.
- Practical Application: The methods were successfully applied for the direct quantitative analysis of GFN in commercial pharmaceutical syrup formulations with excellent accuracy (average recovery near 100%) and high precision (RSD% < 1.3%).
- Process Efficiency: The developed voltammetric methods eliminate the need for complex, time-consuming, and expensive pre-separation steps required by traditional chromatographic techniques.
Technical Specifications
Section titled âTechnical Specificationsâ| Parameter | Value | Unit | Context |
|---|---|---|---|
| Working Electrode Material | Boron Doped Diamond Electrode (BDDE) | 3 mm | Unmodified |
| Optimal Supporting Electrolyte | pH 3.5 Acetate Buffer (AB) | 0.5 M | Used for DPV and SWV |
| Operating Temperature | 25 ± 1 | °C | Room temperature measurement |
| DPV Linearity Range | 0.4 - 100 | ”M | GFN concentration |
| SWV Linearity Range | 0.8 - 100 | ”M | GFN concentration |
| DPV Limit of Detection (LOD) | 1.47 x 10-3 | ”M | Equivalent to 1.47 nM |
| SWV Limit of Detection (LOD) | 2.92 x 10-3 | ”M | Equivalent to 2.92 nM |
| DPV Sensitivity (Slope) | 3.63 x 10-2 ± 5.24 x 10-4 | ”A/”M | Calibration curve slope |
| SWV Sensitivity (Slope) | 2.41 x 10-2 ± 4.39 x 10-4 | ”A/”M | Calibration curve slope |
| DPV Average Recovery | 99.24 | % | Analysis of pharmaceutical syrup |
| SWV Average Recovery | 100.43 | % | Analysis of pharmaceutical syrup |
| SWV Inter-day Precision (RSD) | 1.27 | % | Peak current measurement |
| CV Scan Rate Range | 5 - 200 | mV/s | Used for mechanism study |
| Ep-pH Slope (CV) | -18.0 | mV/pH | Indicates proton/electron transfer mismatch |
Key Methodologies
Section titled âKey MethodologiesâThe electroanalytical investigation of Guaifenesin (GFN) was conducted using a three-electrode cell setup and optimized voltammetric techniques.
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Electrochemical Setup:
- Measurements were performed using an Autolab PGSTAT128N potentiostat/galvanostat.
- The cell consisted of a 3 mm BDDE working electrode, a platinum wire counter electrode, and an Ag/AgCl (3.0 M KCl) reference electrode.
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Reagent and Sample Preparation:
- GFN stock solutions (1.0 x 10-3 M) were prepared daily in ultrapure water.
- Pharmaceutical samples (syrup) were diluted directly with the supporting electrolyte without requiring complex extraction or separation.
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Electrolyte Optimization:
- Cyclic Voltammetry (CV) was used to test GFN behavior across a wide pH range (2.0-12.0) using Britton-Robinson Buffer (BRB), Phosphate Buffer (PB), and Acetate Buffer (AB).
- Result: pH 3.5 Acetate Buffer (AB) was selected as the optimal medium, yielding the highest and most symmetrical oxidation peak current.
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Mechanism Determination (CV):
- CV was performed at varying scan rates (5 to 200 mV/s) in the optimal pH 3.5 AB solution.
- The linear relationship between the peak current (Ip) and the square root of the scan rate (v1/2) confirmed that the GFN oxidation process is diffusion-controlled.
- The absence of a reduction peak confirmed the reaction is irreversible.
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Quantitative Analysis (DPV and SWV):
- DPV and SWV techniques were employed for quantitative analysis due to their enhanced sensitivity compared to CV.
- Calibration curves were generated, and validation parameters (LOD, LOQ, linearity) were calculated using the 3s/m and 10s/m methods, respectively.
- Recovery studies were performed on the pharmaceutical syrup formulation using the established calibration equations.
Commercial Applications
Section titled âCommercial ApplicationsâThe use of BDDE in highly sensitive voltammetric analysis provides significant advantages for industries requiring robust, rapid, and precise chemical sensing.
- Pharmaceutical Quality Control (QC): BDDE-based sensors offer a fast, inexpensive alternative to HPLC for routine QC and stability testing of drug formulations, particularly for expectorants and other APIs.
- High-Throughput Drug Screening: The rapid response time and minimal sample preparation required by voltammetry make it suitable for high-throughput analysis in drug discovery and formulation development.
- Bioanalytical Sensing: BDDEâs resistance to fouling and wide potential window are crucial for developing sensors capable of detecting trace drug metabolites or biomarkers in complex biological matrices (e.g., serum or urine).
- Environmental Electrochemistry: The exceptional stability of BDDE allows for the detection and quantification of organic contaminants and pharmaceutical residues in wastewater or environmental samples, where traditional electrodes may degrade or foul.
- Advanced Sensor Manufacturing: The BDDE material itself is a key component in manufacturing durable electrochemical sensors designed for operation in aggressive chemical environments (high acidity/alkalinity).
View Original Abstract
The expectorant drug guaifenesin (GFN) electroanalytical analysis was performed on boron doped diamond electrode (BDDE) by cyclic voltammetry (CV), differential pulse voltammetry (DPV) and square wave voltammetry (SWV) methods. The results of CV studies indicate that the reaction mechanism of GFN in the oxidation direction on the BDDE is irreversible and diffusion controlled. The linearity ranges are 0.400 Ë 100 ”M and 0.800 Ë 100 ”M for DPV and SWV methods, respectively. Limit of detection (LOD) values are obtained as 1.47 nM for DPV and 2.92 nM for SWV. Quantitative analysis of GFN from the pharmaceuticals was performed with fully validated DPV and SWV methods without any pre-separation. The sensitive methods with good recovery, high precision and accuracy have been developed for the electroanalytical analysis of GFN.