Determination of trace levels of Cd(II) in tap water samples by anodic stripping voltammetry with an electrografted boron-doped diamond electrode
At a Glance
Section titled âAt a Glanceâ| Metadata | Details |
|---|---|
| Publication Date | 2017-01-01 |
| Journal | ScienceAsia |
| Authors | Chalermpol Innuphat, Pipat Chooto |
| Institutions | Prince of Songkla University |
| Citations | 13 |
| Analysis | Full AI Review Included |
6CCVD Technical Analysis: Anodic Stripping Voltammetry (ASV) utilizing Boron-Doped Diamond (BDD) Electrodes for Trace Cadmium Detection
Section titled â6CCVD Technical Analysis: Anodic Stripping Voltammetry (ASV) utilizing Boron-Doped Diamond (BDD) Electrodes for Trace Cadmium DetectionâExecutive Summary
Section titled âExecutive SummaryâThis research validates the use of a modified Boron-Doped Diamond (BDD) electrode in Square Wave Anodic Stripping Voltammetry (SWASV) for highly sensitive, mercury-free determination of trace cadmium (Cd2+) in water samples.
- Core Achievement: Successful application of an electrografted BDD electrode (modified with 4-aminomethyl benzoic acid) to detect Cd2+ in tap water.
- Material Performance: The BDD platform exhibited superb stability, high accuracy, and minimal interference compared to traditional mercury-based electrodes.
- High Sensitivity: The method achieved a remarkably low Limit of Detection (LOD) of 0.2 ”g/l (0.2 ppb), exceeding the sensitivity of many standard voltammetric techniques.
- Analytical Range & Accuracy: Demonstrated linear calibration across the 2-50 ”g/l range (r2 = 0.9989), with excellent recovery (99.02% for SRM 1640) and high reproducibility (RSD 3%).
- Methodology Advantage: The technique offers significant practical benefits, including simpler sample preparation, shorter analysis time, and inexpensive instrumentation compared to ICP-OES or AAS.
- 6CCVD Relevance: This work confirms BDDâs status as the superior electrode material for demanding environmental monitoring and trace heavy metal analysis, directly aligning with 6CCVDâs specialized BDD product line.
Technical Specifications
Section titled âTechnical SpecificationsâThe following optimized performance parameters and physical conditions were achieved using the electrografted BDD electrode for Cd2+ detection:
| Parameter | Value | Unit | Context / Condition |
|---|---|---|---|
| Analyte | Cd2+ | N/A | Trace heavy metal in tap water |
| Electrode Material | BDD, electrografted | N/A | Modified with 0.5 mM 4-aminomethyl benzoic acid |
| Detection Technique | SWASV | N/A | Square Wave Anodic Stripping Voltammetry |
| Stripping Peak Potential | -0.72 | V vs Ag/AgCl | Single, well-defined anodic stripping signal |
| Limit of Detection (LOD) | 0.2 | ”g/l (ppb) | LOD calculated via 3N/m formula |
| Limit of Quantitation (LOQ) | 0.6 | ”g/l (ppb) | LOQ calculated via 10N/m formula |
| Linear Concentration Range | 2-50 | ”g/l (ppb) | Calibration correlation coefficient (r2) = 0.9989 |
| Optimum Deposition Potential | -1.10 | V vs Ag/AgCl | Selected for high sensitivity/better response |
| Optimum Accumulation Time | 6 (360) | min (s) | Reflects surface saturation |
| Optimum Scan Rate | 100 | mV/s | Selected for best stability and current response |
| Supporting Electrolyte | pH 6.0 | N/A | Acetate buffer solution |
| Metal Recovery (SRM 1640) | 99.02 | % | Verified against NIST certified natural water standard |
Key Methodologies
Section titled âKey MethodologiesâThe highly successful detection relies on precise preparation and application of the BDD working electrode.
I. Electrode Preparation (Electrografting)
Section titled âI. Electrode Preparation (Electrografting)â- Polishing: The BDD electrode surface was polished using a 0.05 ”m alumina slurry prior to use to ensure surface uniformity.
- Diazotization (In Situ): Diazonium salts (4-aminomethyl benzoic acid) were generated directly in the electrochemical cell using aqueous nitrite solution (10 mM TBAPF, 0.5 M HCl, pH 2) in contact with the BDD.
- Electrochemical Grafting: The BDD was modified under stirring (400 rpm) via Cyclic Voltammetry (CV) mode (5 cycles).
- Potential Range: 0.2 V to -1.2 V vs Ag/AgCl.
- Scan Rate (Grafting): 100 mV/s.
- Wettability Change: Grafting resulted in increased hydrophobicity, changing the contact angle from 22° (bare BDD) to 68° (modified BDD), essential for surface interaction with the analyte.
- Optimum Modifier Concentration: The highest current response was achieved at 0.5 mM 4-aminomethyl benzoic acid.
II. Anodic Stripping Voltammetry (SWASV) Procedure
Section titled âII. Anodic Stripping Voltammetry (SWASV) Procedureâ- Solution Control: Measurements were conducted in a 50 ml cell using pH 6.0 acetate buffer solution.
- Deaeration: Nitrogen gas (99.99%) was used to deaerate the testing solution for 2 minutes.
- Deposition/Preconcentration:
- Deposition Potential: -1.10 V vs Ag/AgCl.
- Deposition Time: 6 minutes (360 s) under stirring.
- Quiet Time: Stirring was stopped for a 30 second equilibration period before measurement.
- Stripping Measurement: The voltammogram was recorded by sweeping the potential from -1.0 V to -0.3 V.
- Scan Rate (Stripping): 100 mV/s.
- Frequency: 10 Hz.
- Amplitude: 4 mV.
- Potential Step: 25 mV.
- Conditioning: A 30 second conditioning step at +0.3 V (stirred solution) was applied after each run to fully oxidize any remaining metal deposits.
6CCVD Solutions & Capabilities
Section titled â6CCVD Solutions & Capabilitiesâ6CCVD provides the high-performance diamond materials necessary to replicate and advance this cutting-edge research in heavy metal sensing and environmental monitoring.
Applicable Materials
Section titled âApplicable MaterialsâThe foundation of this successful SWASV technique is the superior quality and electrochemical stability of the Boron-Doped Diamond (BDD) electrode.
| 6CCVD Material Recommendation | Specification Alignment | Application Context |
|---|---|---|
| Heavy Boron-Doped Diamond (BDD) Wafers | High concentration B-doping required for maximized conductivity and wide potential window in aqueous media (essential for ASV). | Electrochemical Sensors, Environmental Monitoring, Wastewater Treatment, and robust analytical platforms. |
| Polycrystalline Diamond (PCD) Substrates | Available up to 125mm in size and thicknesses up to 10mm, suitable for large-scale production of multiple electrodes or devices. | Custom electrode fabrication for industrial ASV or high-throughput sensor arrays. |
| Custom Polished SCD/PCD/BDD | Surface preparation is critical (paper used 0.05 ”m alumina slurry). 6CCVD guarantees Ra < 5nm for inch-size PCD/BDD. | Ensures maximum uniformity, low background current, and reproducibility, critical for achieving the high sensitivity (0.2 ppb LOD) reported. |
Customization Potential
Section titled âCustomization PotentialâThe referenced paper utilized a BDD electrode with a 3 mm inner diameter, demonstrating the necessity of custom component fabrication. 6CCVD specializes in fulfilling exact geometric and surface interface requirements:
- Custom Dimensions and Geometry: We provide MPCVD BDD plates and wafers that can be laser-cut, machined, or etched to create custom electrode shapes, sizes (discs, microarrays, etc.), and dimensions up to 125mm.
- Surface Preparation: 6CCVD offers expert in-house polishing services (Ra < 5nm for PCD) ensuring the pristine surface quality required for subsequent electrochemical functionalization (e.g., diazonium grafting).
- Metalization Interfaces: While the reported work used a standard Ag/AgCl reference, 6CCVD offers custom metalization (Ti, Au, Pt, Pd, etc.) if researchers wish to integrate on-chip reference or counter electrodes directly onto the BDD surface for miniaturized sensor systems.
Engineering Support & Logistics
Section titled âEngineering Support & Logisticsâ6CCVDâs in-house PhD engineering team is available to assist customers in selecting the appropriate BDD doping levels, thickness, and surface finish required to replicate or extend high-performance Anodic Stripping Voltammetry (ASV) platforms for heavy metal detection (Cd2+, Pb2+, Cu2+, etc.).
We provide global logistics support, offering DDU (Delivered Duty Unpaid) default shipping with DDP (Delivered Duty Paid) options available upon request, ensuring reliable delivery of high-value diamond materials worldwide.
Call to Action
Section titled âCall to ActionâFor custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.
View Original Abstract
A boron-doped diamond electrode modified by 0.5 mM 4-aminomethyl benzoic acid was used for electrochemical determination of Cd 2+ in tap water samples by anodic stripping voltammetry.This method is based on the electrochemical reduction of 4-aminomethyl benzoic acid on the electrode followed by the determination of Cd 2+ with a single well-defined reduction peak at -0.72 V versus Ag/AgCl in acetate buffer solutions at pH 6.0.Optimal conditions were established with respect to electrode pretreatment, time accumulation, potential accumulation, scan rate, and pH.Accurate (r 2 = 0.9989, n = 6) calibration curves were obtained for Cd 2+ concentrations ranging between 2 ppb and 50 ppb.Other dissolved metals (Ca, Mg, Zn, Mn, Fe, Cu, Al, Co, Pb, and Ni) have no interference on the Cd 2+ calibration curves.The achieved detection limit was 0.2 ppb.High accuracy and reproducibility of the results as well as excellent stability of the electrode material proves superb capabilities of this Cd 2+ detection system.Recovery in the range of 97-102% further confirmed the usefulness of the proposed method to analyse Cd 2+ in tap water samples.The results with SRM1640 were in good agreement with those by inductively coupled plasma optical emission spectrometry.