Square-Wave Voltammetric Sensing of Lawsone (2- Hydroxy-1,4-Naphthoquinone) Based on the Enhancement Effect of Cationic Surfactant on Anodically Pretreated Boron-Doped Diamond Electrode

At a Glance

Metadata	Details
Publication Date	2021-12-06
Journal	Acta chimica slovenica
Authors	Pınar Talay Pınar, Yavuz Yardım, Zühre Şentürk
Institutions	Van Yüzüncü Yıl Üniversitesi
Citations	12
Analysis	Full AI Review Included

Technical Documentation & Analysis: Lawsone Sensing on Boron-Doped Diamond

This document analyzes the research paper “Square-Wave Voltammetric Sensing of Lawsone… on Anodically Pretreated Boron-Doped Diamond Electrode” to highlight the critical role of high-quality MPCVD Boron-Doped Diamond (BDD) and connect the experimental requirements directly to 6CCVD’s advanced material capabilities.

Executive Summary

First Successful Application: This work reports the first successful electrochemical oxidation and detection of Lawsone (a natural dye) using a Boron-Doped Diamond (BDD) electrode.
Surface Optimization Critical: Optimal electroanalytical performance was achieved using an Anodically Pre-Treated (APT) BDD surface (+1.8 V for 180 s), confirming the necessity of controlled oxygen termination for this specific analyte.
Cationic Surfactant Enhancement: The addition of the cationic surfactant CTAB significantly enhanced the oxidation peak current by a factor of 4, demonstrating a highly sensitive, diffusion-controlled process.
High Sensitivity Achieved: The method, utilizing Square-Wave Voltammetry (SWV), yielded a low Detection Limit (LOD) of 0.029 µM and a Quantification Limit (LOQ) of 0.097 µM.
Practical Validation: The developed APT-BDD methodology was successfully applied for the quantification of Lawsone in complex commercial samples (henna), showing high recovery rates (91.8% to 103.7%).
Material Specification: The experiment relied on a BDD electrode with a declared boron doping level of 1000 ppm, emphasizing the need for precisely controlled MPCVD diamond materials.

Technical Specifications

The following hard data points were extracted from the experimental methodology and results sections of the paper.

Parameter	Value	Unit	Context
Electrode Material	Boron-Doped Diamond (BDD)	N/A	Working Electrode
Boron Doping Level	1000	ppm	Declared concentration
Electrode Diameter	3	mm	Custom geometry
Geometric Surface Area	0.07	cm²	Used for current density calculations
Anodic Pre-Treatment Potential	+1.8	V	Applied for 180 seconds in 0.5 M H₂SO₄
Lawsone Oxidation Peak Potential	+0.19	V (vs. Ag/AgCl)	Observed using Cyclic Voltammetry (CV)
Optimal SWV Frequency (f)	75	Hz	Instrumental parameter for high sensitivity
Optimal SWV Pulse Amplitude (ΔE_sw)	60	mV	Instrumental parameter
Detection Limit (LOD)	0.029	µM	Achieved using SWV with CTAB enhancement
Quantification Limit (LOQ)	0.097	µM	Achieved using SWV with CTAB enhancement
Intraday Repeatability (RSD)	5.43	%	Relative Standard Deviation (n=10)
Interday Repeatability (RSD)	6.87	%	Relative Standard Deviation (3 consecutive days)

Key Methodologies

The successful detection relies heavily on precise material selection and a controlled electrochemical pre-treatment recipe.

BDD Electrode Specification: A BDD electrode with a 3 mm diameter and a declared boron doping level of 1000 ppm was utilized.
Anodic Pre-Treatment (APT): The BDD surface was electrochemically pre-treated daily by applying a potential of +1.8 V (vs. Ag/AgCl) for 180 seconds in 0.5 M H₂SO₄. This step was crucial for creating a predominantly oxygen-terminated surface, which enhanced the oxidation signal.
Supporting Electrolyte: The optimal medium was determined to be 0.1 M Phosphate Buffer Solution (PBS) at pH 2.5, maximizing the Lawsone peak current.
Surfactant Enhancement: The cationic surfactant Cetyltrimethylammonium Bromide (CTAB) was added at 0.1 mM concentration to the PBS solution, resulting in a four-fold increase in peak current intensity compared to non-surfactant conditions.
Voltammetric Analysis: Square-Wave Voltammetry (SWV) was performed using optimized parameters (f = 75 Hz, ΔE = 14 mV, ΔE_sw = 60 mV) to achieve high sensitivity and linearity across the 0.1-5.0 µM concentration range.

6CCVD Solutions & Capabilities

This research validates the critical role of high-quality, precisely doped BDD electrodes in advanced electroanalytical sensing. 6CCVD is uniquely positioned to supply the materials required to replicate, scale, and extend this research.

Applicable Materials

To replicate the high-performance sensing demonstrated in this paper, researchers require materials with tightly controlled doping and surface quality:

Electroanalytical Grade BDD (Boron-Doped Diamond): 6CCVD specializes in MPCVD BDD wafers and plates. We can precisely match the required 1000 ppm boron doping level or provide heavier doping for applications requiring higher conductivity and metallic behavior.
Custom Thickness: We offer BDD layers ranging from 0.1 µm up to 500 µm, allowing engineers to optimize the diamond film thickness based on the specific application (e.g., thin films for microelectrodes or thick films for robust industrial sensors).

Customization Potential

The paper utilized a small, custom-sized 3 mm diameter electrode. 6CCVD’s fabrication capabilities eliminate the need for researchers to perform complex in-house cutting and dicing:

Requirement from Paper	6CCVD Customization Service
Small, Custom Electrode Geometry (3 mm disc)	Precision Laser Cutting & Dicing: We provide custom-cut BDD electrodes in any required shape or size, from microelectrodes to the 3 mm discs used in this study. We supply plates/wafers up to 125 mm (PCD).
Need for Electrical Contacting	Integrated Metalization: 6CCVD offers in-house deposition of standard contact metals (Au, Pt, Ti, W, Cu) directly onto the BDD surface, ensuring robust, low-resistance electrical connections necessary for reproducible voltammetry.
Surface Quality for Pre-Treatment	Ultra-Low Roughness Polishing: While the paper used electrochemical pre-treatment, starting with a superior surface is key. We offer polishing down to Ra < 5 nm for inch-size PCD, providing an ideal, reproducible starting point for surface termination protocols.

Engineering Support

The successful implementation of the Anodic Pre-Treatment (APT) protocol highlights the importance of understanding diamond surface chemistry.

Expert Consultation: 6CCVD’s in-house PhD team provides specialized engineering support for projects involving electroanalytical sensing, water treatment, and advanced electrochemistry. We assist clients in selecting the optimal BDD doping concentration, thickness, and initial surface termination (hydrogen or oxygen) to maximize performance for specific analytes like quinones or dyes.
Global Supply Chain: We ensure reliable, global shipping (DDU default, DDP available) of highly sensitive diamond materials, supporting research continuity worldwide.

For custom specifications or material consultation, visit 6ccvd.com or contact our engineering team directly.

View Original Abstract

In this reported work, an anodically pretreated boron-doped diamond (BDD) electrode was used for the inexpensive, simple and quick detection of a natural dye, lawsone. Lawsone had a well-defined, irreversible and diffusion-controlled oxidation peak at approximately +0.19 V in phosphate buffer solution (PBS, 0.1 M, pH 2.5) using cyclic voltammetry (CV). The oxidation peak heights of lawsone were significantly increased in PBS using the cationic surfactant cetyltrimethylammonium bromide (CTAB). Under optimized experimental conditions, the calibration curve was linear over a concentration range of 0.1-5.0 μM with detection limit of 0.029 μM in 0.1 M PBS (pH 2.5) containing 0.1 mM CTAB by using square-wave voltammetry (SWV). To evaluate the practical applicability of the BDD electrode, it was used for the quantification of lawsone in commercial henna, a natural dye made from the leaves of the henna plant.

Tech Support

Original Source

DOI: https://doi.org/10.17344/acsi.2020.6617