Graphene Oxide Electroreduced onto Boron-Doped Diamond and Electrodecorated with Silver (Ag/GO/BDD) Electrode for Tetracycline Detection in Aqueous Solution

At a Glance

Metadata	Details
Publication Date	2021-06-14
Journal	Nanomaterials
Authors	Sorina Negrea, Lidia Ani Diaconu, Valeria Nicorescu, Sorina Motoc, Corina Orha
Institutions	Polytechnic University of Timişoara, National Institute of Research and Development for Electrochemistry and Condensed
Citations	18
Analysis	Full AI Review Included

Technical Documentation & Analysis: Ag/GO/BDD Electrode for Tetracycline Detection

Executive Summary

This research successfully demonstrates the fabrication and superior electroanalytical performance of a Silver/Graphene Oxide/Boron-Doped Diamond (Ag/GO/BDD) electrode for the detection of Tetracycline (TC) in aqueous solutions. The findings validate the synergistic role of BDD as a stable, high-performance substrate combined with nanostructured modifiers, presenting a significant opportunity for 6CCVD to supply high-specification diamond materials to the electrochemical sensing market.

Record Sensitivity: The Ag/GO/BDD sensor achieved a best-in-class Limit of Detection (LOD) of 5 nM (0.005 µM) for Tetracycline, demonstrating superior performance compared to over ten previously reported modified electrodes.
Material Synergy: The combination of the robust BDD substrate, electrochemically reduced Graphene Oxide (GO), and electrodeposited Silver (Ag) provided enhanced electrocatalytic activity and improved electron transfer kinetics.
Optimal Technique: Optimal performance (Sensitivity: 46.6 µA·µM⁻¹·cm⁻²) was achieved using Square-Wave Voltammetry (SWV) operated at a step potential of 5 mV and a modulation amplitude of 200 mV in 0.1 M NaOH.
Practical Application: The method demonstrated high recovery rates (> 95%) and low Relative Standard Deviation (RSD < 5%), validating its potential for quantitative determination in pharmaceutical formulations (using NaOH) and environmental water monitoring (using Na₂SO₄ to mitigate chloride interference).
Substrate Requirement: The study relied on the intrinsic stability and wide potential window of Boron-Doped Diamond (BDD), confirming BDD as the material of choice for advanced electrochemical sensor development.

Technical Specifications

The following hard data points were extracted from the electroanalytical performance tests, primarily focusing on the optimized Square-Wave Voltammetry (SWV) results in 0.1 M NaOH.

Parameter	Value	Unit	Context
Lowest Limit of Detection (LOD)	0.005	µM	SWV, 0.1 M NaOH
Best Sensitivity	46.6	µA·µM⁻¹·cm⁻²	SWV, 0.1 M NaOH
Optimal Detection Potential (E_det)	+0.750	V/SCE	SWV, 0.1 M NaOH
Electroactive Surface Area (Ag/GO/BDD)	0.045	cm²	Determined via Randles-Sevcik Equation
SWV Modulation Amplitude (MA)	200	mV	Optimal setting for 0.1 M NaOH
SWV Step Potential (SP)	5	mV	Optimal setting for 0.1 M NaOH
SWV Frequency (f)	10	Hz	Optimal setting
TC Recovery Rate (Water Samples)	> 95	%	0.1 M Na₂SO₄ supporting electrolyte
Relative Standard Deviation (RSD)	0.135	%	SWV, 0.1 M NaOH
Geometrical Electrode Area (Commercial BDD)	0.09	cm²	3 mm disc diameter

Key Methodologies

The Ag/GO/BDD electrode was fabricated using a sequential electrochemical modification process on a commercial BDD substrate.

Substrate Preparation: Commercial BDD electrodes (3 mm diameter discs) were mechanically cleaned using 0.2 µm alumina powder (Al₂O₃) and washed with distilled water.
Graphene Oxide (GO) Electroreduction: GO was deposited onto the BDD surface using Chronoamperometry (CA) at a potential of -1.50 V/SCE for 120 seconds. The precursor was a 4 mg/mL GO suspension in water.
Silver (Ag) Electrodeposition: Silver particles (AgPs) were decorated onto the GO/BDD surface via electrodeposition at -1.30 V/SCE for 5 seconds, using a 4 mM AgNO₃ solution.
Electrochemical Stabilization: Working electrodes were stabilized using 10 continuous repetitive Cyclic Voltammograms (CV) between -0.50 V and +1.00 V/SCE in 0.1 M NaOH.
Electrolyte Selection: Comparative testing was performed using 0.1 M NaOH (alkaline medium, optimal sensitivity) and 0.1 M Na₂SO₄ (sulfate medium, used for practical water monitoring to eliminate chloride interference).
Analytical Techniques: The electroanalytical performance was evaluated using Cyclic Voltammetry (CV), Differential-Pulsed Voltammetry (DPV), Square-Wave Voltammetry (SWV), Chronoamperometry (CA), and Multiple-Pulsed Amperometry (MPA).

6CCVD Solutions & Capabilities

6CCVD is uniquely positioned to supply the high-performance Boron-Doped Diamond (BDD) substrates required to replicate and advance this cutting-edge electrochemical sensing research. Our MPCVD capabilities ensure materials meet the stringent demands of high-sensitivity detection systems.

Research Requirement	6CCVD Solution & Capability	Technical Advantage for Replication/Extension
High-Purity BDD Substrate (Core material for stability)	Heavy Boron-Doped Diamond (BDD) Wafers. Available in Single Crystal (SCD) or Polycrystalline (PCD) formats.	Provides the necessary wide potential window, low background current, and chemical inertness essential for robust sensing, particularly in harsh alkaline (NaOH) or acidic environments.
Custom Electrode Dimensions (3 mm disc used)	Custom Dimensions & Precision Laser Cutting. We supply plates/wafers up to 125 mm (PCD) and offer in-house laser cutting services to achieve precise geometries (e.g., 3 mm discs, microelectrode arrays, or custom flow-cell inserts).	Enables rapid prototyping and scaling from laboratory-scale discs to industrial-sized arrays or integrated sensor chips, ensuring consistency across batches.
Electrode Decoration (Ag/GO)	Advanced Metalization Services (Au, Pt, Ag, Ti, W, Cu). Internal capability for thin-film deposition.	Researchers can order BDD substrates pre-metalized with a high-purity Silver (Ag) layer, ensuring uniform coverage and superior adhesion compared to simple electrodeposition, thereby improving sensor reproducibility.
Surface Quality for Modification (Needed for uniform GO/Ag deposition)	Ultra-Low Roughness Polishing. SCD (Ra < 1 nm), Inch-size PCD (Ra < 5 nm).	A superior, atomically flat surface finish ensures highly uniform deposition of nanostructured materials (GO, Ag), leading to enhanced electrocatalytic efficiency and better signal-to-noise ratios than mechanically cleaned surfaces.
Material Optimization (Doping level, thickness)	Expert Engineering Support. Our in-house PhD team assists with optimizing BDD doping levels and thickness (SCD/PCD available from 0.1 µm to 500 µm) to maximize charge transfer kinetics for specific applications like Tetracycline detection.	We provide material consultation to tailor the BDD properties, ensuring the substrate perfectly complements the GO/Ag modification strategy for maximum sensitivity and long-term stability.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly. We ship globally (DDU default, DDP available).

View Original Abstract

A new electrochemical sensor designed by modifying the commercial boron-doped diamond (BDD) electrode with graphene oxide (GO) reduced electrochemically and further electrodecorated with silver (Ag), named the Ag/GO/BDD electrode, was selected among a series of the BDD, GOelectroreduced onto BDD (GO/BDD) and silver electrodeposited onto BDD (Ag/BDD) electrodes for the detection of tetracycline (TC) in aqueous solution. The best results regarding the sensitivity of 46.6 µA·µM−1·cm−2 and the lowest limit of detection of 5 nM was achieved using square-wave voltammetry (SWV) operated at the step potential of 5 mV, modulation amplitude of 200 mV and the frequency of 10 Hz in alkaline medium. The application of the alkaline supporting electrolyte-based procedure is limited for water monitoring due to the presence of chloride that interferes with TC detection; however, it can be applied for quantitative determination of pharmaceutical formulations. 0.1 M Na2SO4 supporting electrolyte eliminated chloride interference and can be used for the application of Ag/GO/BDD in practical detection of TC in water.

Tech Support

Original Source

DOI: https://doi.org/10.3390/nano11061566

References

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