Voltammetric quantification of a nonsteroidal anti-inflammatory agent diflunisal based on the enhancement effect of cationic surfactant on boron-doped diamond electrode
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2021-05-11 |
| Journal | Macedonian Journal of Chemistry and Chemical Engineering |
| Authors | ErtuÄrul Keskin, Shabnam Allahverdiyeva, Amer S. Alali, Yavuz Yardım |
| Institutions | Van YĂŒzĂŒncĂŒ Yıl Ăniversitesi, Adıyaman University |
| Citations | 5 |
| Analysis | Full AI Review Included |
Technical Documentation & Analysis: BDD for High-Sensitivity Voltammetry
Section titled âTechnical Documentation & Analysis: BDD for High-Sensitivity VoltammetryâExecutive Summary
Section titled âExecutive SummaryâThis research successfully demonstrates a simple, fast, and highly sensitive voltammetric method for quantifying the nonsteroidal anti-inflammatory drug (NSAID) Diflunisal (DIF) using an unmodified Boron-Doped Diamond (BDD) electrode.
- Core Achievement: Developed a robust Square-Wave Adsorptive Stripping Voltammetry (SW-AdSV) protocol for DIF quantification in pharmaceutical formulations.
- Material Advantage: The BDD electrode provided the necessary wide working potential window and low background current for the irreversible, diffusion-controlled oxidation of DIF.
- Sensitivity Enhancement: The presence of the cationic surfactant, cetyltrimethylammonium bromide (CTAB), combined with a 30 s accumulation step, increased the DIF oxidation signal sensitivity by a factor of 6.8.
- High Performance: The optimized method achieved a low Limit of Detection (LOD) of 5.2·10-8 mol l-1 (0.013 ”g ml-1) and excellent linearity (r = 0.999).
- Practical Application: The protocol proved highly selective and accurate, demonstrating successful quantification of DIF in commercial tablet samples with high recovery rates (99.3% to 108.4%).
- Surface Management: An optimized anodic/cathodic pretreatment procedure was essential to maintain the BDD surfaceâs oxygen- and hydrogen-terminated properties, ensuring stable and reproducible voltammetric responses.
Technical Specifications
Section titled âTechnical SpecificationsâThe following hard data points were extracted from the optimized electroanalytical protocol utilizing the BDD electrode:
| Parameter | Value | Unit | Context |
|---|---|---|---|
| Electrode Material | Boron-Doped Diamond (BDD) | N/A | Unmodified working electrode |
| Boron Doping Level | 1000 | ppm | Specified concentration |
| Electrode Diameter | 3 | mm | Physical dimension of the working electrode |
| Technique Used | SW-AdSV (Square-Wave Adsorptive Stripping Voltammetry) | N/A | Optimized pulse technique |
| Supporting Electrolyte | 0.1 mol l-1 Phosphate Buffer Solution (PBS) | N/A | Optimized for highest peak morphology |
| Optimum pH | 2.5 | N/A | Selected buffer acidity |
| Cationic Surfactant | CTAB (Cetyltrimethylammonium bromide) | N/A | Used for sensitivity enhancement |
| Optimum CTAB Concentration | 5·10-5 | mol l-1 | Concentration yielding 6.8x sensitivity increase |
| Accumulation Time | 30 | s | Applied at open-circuit potential |
| Oxidation Peak Potential (Ep) | +1.07 | V | vs. Ag/AgCl reference electrode |
| Linear Range (Molar) | 2.0·10-7 - 8.0·10-6 | mol l-1 | Analytical working range |
| Limit of Detection (LOD) | 5.2·10-8 | mol l-1 | High sensitivity achieved |
| SWV Frequency (f) | 75 | Hz | Optimized instrumental parameter |
| SWV Pulse Amplitude (ÎEsw) | 40 | mV | Optimized instrumental parameter |
| SWV Step Potential (ÎEs) | 10 | mV | Optimized instrumental parameter |
Key Methodologies
Section titled âKey MethodologiesâThe successful quantification of DIF relied on precise control over the BDD electrode surface and optimized SWV parameters:
- Electrode Pretreatment (Surface Termination): The BDD electrode was subjected to a sequential anodic/cathodic pretreatment at the start of each experiment day to achieve stable oxygen- and hydrogen-terminated properties.
- Anodic Step: +1.8 V applied for 180 s in 0.5 mol l-1 H2SO4.
- Cathodic Step: -1.8 V applied for 180 s in 0.5 mol l-1 H2SO4.
- Physical Cleaning: The electrode was gently polished with a polishing pad and rinsed with deionized water before each voltammetric experiment to ensure stable responses.
- Electrolyte Optimization: Phosphate Buffer Solution (PBS) at pH 2.5 was selected as the optimum supporting electrolyte, providing the highest and most uniform peak morphology compared to Britton-Robinson (BR) buffer and HNO3 solutions.
- SWV Parameter Optimization: Instrumental parameters were tuned for maximum sensitivity and peak shape: frequency (75 Hz), pulse amplitude (40 mV), and step potential (10 mV).
- Adsorptive Stripping Protocol (SW-AdSV):
- The three electrodes were immersed in the supporting electrolyte containing DIF and the optimum CTAB concentration (5·10-5 mol l-1).
- Accumulation: 30 s at open-circuit potential while stirring (500 rpm).
- Equilibration: 5 s pause after stirring stopped.
- Measurement: Anodic scanning from 0 V to +1.5 V using the optimized SWV technique.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD is the premier supplier of MPCVD diamond materials necessary to replicate and advance this high-sensitivity electroanalytical research. Our expertise in custom BDD fabrication ensures optimal performance for demanding applications like pharmaceutical sensing.
Applicable Materials
Section titled âApplicable MaterialsâTo replicate or extend the high-sensitivity DIF detection achieved in this paper, researchers require highly controlled Boron-Doped Diamond (BDD) material:
- Heavy Boron Doped PCD/SCD (BDD): The core material required. 6CCVD offers BDD with precise control over boron concentration, easily meeting or exceeding the 1000 ppm doping level used in this study. We provide BDD optimized for electrochemical applications, ensuring the wide working window and low background current critical for SW-AdSV.
- Electroanalytical Grade PCD: For applications requiring larger surface areas or arrays, our Polycrystalline Diamond (PCD) substrates can be heavily doped with boron, offering robust, scalable platforms up to 125 mm in diameter.
Customization Potential
Section titled âCustomization PotentialâThe success of this research hinges on precise electrode geometry and surface quality. 6CCVD provides tailored solutions that eliminate the need for external processing:
| Research Requirement | 6CCVD Custom Capability | Value Proposition |
|---|---|---|
| Specific Dimensions | Custom laser cutting and shaping. | We can supply BDD wafers cut precisely to 3 mm diameter electrodes, or larger plates (up to 125 mm) for fabricating multi-electrode arrays. |
| Doping Uniformity | Tight control over gas phase B/C ratio during MPCVD growth. | Ensures highly uniform 1000 ppm (or custom) boron incorporation, guaranteeing reproducible electrochemical performance across batches. |
| Surface Finish | Ultra-smooth polishing services. | We offer polishing down to Ra < 5 nm for inch-size PCD/BDD, which is essential for minimizing fouling and maximizing the stability and reproducibility of the voltammetric response, as noted in the paper. |
| Integrated Contacts | Custom metalization services (Au, Pt, Ti, W, Cu). | We can deposit custom metal contacts directly onto the BDD substrate, streamlining integration into electrochemical cell setups and ensuring low-resistance connections for high-frequency SWV measurements. |
Engineering Support
Section titled âEngineering SupportâThe optimization of BDD surface termination (anodic/cathodic pretreatment) is crucial for achieving the reported sensitivity. 6CCVDâs in-house PhD team specializes in diamond surface chemistry and electrochemistry.
- Application Expertise: Our team can assist engineers and scientists in selecting the optimal BDD material (doping level, thickness, and surface termination) for similar pharmaceutical electroanalytical sensing projects, including the detection of other NSAIDs or complex organic molecules.
- Process Consultation: We provide consultation on best practices for BDD electrode preparation and pretreatment procedures to maximize sensitivity and lifetime in corrosive environments (e.g., 0.5 mol l-1 H2SO4).
For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
The present work describes a simple, fast, and inexpensive voltammetric method for diflunisal measurement using a non-modified boron-doped diamond (BDD) electrode. The oxidation of the agent was irreversible and presented a diffusionâcontrolled process. The sensitivity of the square wave voltammetric measurements were significantly improved when the cationic surfactant, cetyltrimethylammonium bromide (CTAB), was present in the supporting electrolyte solution. Using square-wave mode, a linear response was obtained for diflunisal quantification in 0.1 mol L-1 phosphate buffer solution (pH 2.5) solution containing 5Ă10-5 mol L-1 CTAB at +1.07 V (vs. Ag/AgCl) (after 30 s accumulation under open-circuit conditions). Linearity was found for 0.05 to 2.0 ÎŒg mL-1 (2.0Ă10-7-8.0Ă10-6 mol L-1) with a detection limit 0.013 ÎŒg mL-1 (5.2Ă10-8 mol L-1). The developed approach could be used for the quantification of diflunisal in pharmaceutical formulations.