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Highly Selective Electrochemical Determination of Phlorizin Using Square Wave Voltammetry at a Boron-Doped Diamond Electrode

MetadataDetails
Publication Date2017-05-30
JournalFood Analytical Methods
AuthorsEda Mehmeti, Dalibor Stanković, Astrid Ortner, Janez Zavaơnik, Kurt Kalcher
InstitutionsJoĆŸef Stefan Institute, University of Graz
Citations19
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Technical Analysis and Documentation: Boron-Doped Diamond for Highly Selective Electrochemical Sensing

Section titled “Technical Analysis and Documentation: Boron-Doped Diamond for Highly Selective Electrochemical Sensing”

This document analyzes the research detailing the use of a Boron-Doped Diamond (BDD) electrode for the highly selective, simple, and rapid determination of Phlorizin (Phl) using Square Wave Voltammetry (SWV). This application validates BDD as a superior, robust sensor platform for complex analytical chemistry and bio-sensing.

  • Superior Material Performance: BDD exhibited chemical inertness, low background currents, and a wide potential window, making it ideal for the highly sensitive determination of the phenolic compound Phl.
  • High Sensitivity and Linearity: The BDD sensor achieved a wide linear dynamic range (3 to 100 ”M) and an excellent Limit of Detection (LOD) of 0.23 ”M.
  • Excellent Repeatability: The method demonstrated high reliability with a repeatability (RSD) of ± 0.9% for seven measurements.
  • Specific Material Requirements: Successful replication requires high-quality BDD characterized by low resistivity (0.075 Ω cm) and high boron doping (1000 mg/dm3).
  • Application Success: The developed method was successfully applied to complex real-world samples, achieving satisfactory recovery rates in both apple root extracts (up to 103% recovery) and human urine samples (up to 103% recovery).
  • Cost-Effective Replacement: The BDD-based electrochemical method serves as a highly effective, fast, and low-cost alternative to traditional, expensive separation techniques like HPLC or NMR-MS.

The following critical parameters and performance metrics were extracted from the research for the BDD sensor platform:

ParameterValueUnitContext
Electrode MaterialBoron-Doped Diamond (BDD)N/AWorking electrode
BDD Resistivity0.075Ω cmMaterial specification
Boron Doping Level1000mg/dm3Material specification
Electrode Inner Diameter3mmEmbedded in PEEK body
Optimal Supporting ElectrolyteBritton-Robinson Buffer (BR)pH 6.0Condition for peak current maximization
Phl Oxidation Peak Potential+0.9VVersus Ag/AgCl (3 M KCl) reference
Linear Dynamic Range (LDR)3 to 100”MPhlorizin concentration range
Limit of Detection (LOD)0.23”MCalculated sensitivity (3σ/slope)
Repeatability (RSD)± 0.9%For c = 10 ”M Phl (n = 7 measurements)
SWV Optimized Scan Rate0.05V/sQuantitative determination
SWV Optimized Pulse Amplitude0.01VQuantitative determination
SWV Optimized Frequency20HzQuantitative determination

The following steps and material specifications were crucial for achieving the reported analytical performance:

  1. Cleaning: The BDD electrode surface was maintained with a mirror-like appearance by cleaning with deionized water and gentle rubbing with a damp silk cloth.
  2. Electrode Pretreatment (New Electrodes):
    • Anodic Pretreatment: Applied +2 V for 180 s in 1 M H2SO4.
    • Cathodic Pretreatment: Applied -2 V for 180 s to renew the hydrogen-terminated surface, crucial for electrochemical stability.
  1. Cell Configuration: A standard 10 mL glass electrochemical cell was used, employing a three-electrode system:
    • Working Electrode: Boron-Doped Diamond (BDD).
    • Reference Electrode: Ag/AgCl (3 M KCl).
    • Auxiliary Electrode: Platinum (Pt) wire.
  2. Supporting Electrolyte: Britton-Robinson (BR) buffer, prepared by mixing 40 mM solutions of phosphoric acid, acetic acid, and boric acid.
  3. pH Adjustment: The final pH of the BR buffer was precisely adjusted to 6.0 using 0.2 M sodium hydroxide (NaOH) solution.
  1. Cyclic Voltammetry (CV) Parameters (Electrochemical Study):
    • Scan Rate: 0.1 V/s.
    • Potential Range: 0 to +1.5 V (versus Ag/AgCl).
  2. Square Wave Voltammetry (SWV) Parameters (Quantitative Determination):
    • Potential Range: 0 to +1.5 V.
    • Scan Rate: 0.05 V/s.
    • Pulse Amplitude: 0.01 V.
    • Frequency: 20 Hz.

6CCVD is uniquely positioned to supply the materials and custom engineering necessary to replicate or advance the sensitive electrochemical sensing work described in this paper. Our capabilities ensure precision in material quality, geometry, and surface preparation, which are critical for low-current voltammetric applications.

Replicating this research requires high-conductivity, low-resistivity Boron-Doped Diamond (BDD).

Requirement from Paper6CCVD Material SolutionWhy 6CCVD is the Expert Solution
High Doping Level (1000 mg/dm3)Heavy Boron-Doped PCD/BDD plates and wafers.6CCVD routinely manufactures BDD with precise, high doping concentrations necessary to achieve the low resistivity (0.075 Ω cm) required for fast electron transfer and wide potential windows.
Custom Electrode Size (3 mm diameter disk)Custom Geometries via Laser Cutting.We offer high-precision laser cutting to produce standard disk electrodes (3 mm, 5 mm) or custom micro-electrode arrays from BDD plates, ready for integration into PEEK or inert housings.
Ultra-Low ResistivityCustom Thin-Film BDD (High Purity)We guarantee resistivity measurements and consistency across wafers, ensuring minimal ohmic drop and maximizing signal integrity for highly sensitive SWV measurements.

The success of the BDD electrode depends heavily on its mounting and physical characteristics. 6CCVD provides comprehensive customization to meet engineering requirements:

  • Dimensional Accuracy: We provide BDD plates and wafers up to 125 mm (PCD/BDD), and can laser cut specific shapes, including disks and complex geometries needed for embedding or micro-sensor integration.
  • Surface Preparation: The paper stressed the need for a “mirror-like appearance.” 6CCVD specializes in ultra-smooth polishing, achieving surface roughness (Ra) of < 5 nm for inch-size BDD/PCD wafers, guaranteeing optimal electrochemically active surface quality and low background capacitance.
  • Metalization and Integration: While this paper did not require metal contact, 6CCVD offers internal metalization services (Au, Pt, Pd, Ti, W, Cu) for engineers needing robust backside contacts or specialized micro-contact fabrication for simplified integration into potentiostats.

6CCVD’s commitment extends beyond material supply. We offer specialized technical support for electrochemical applications:

  • Expert Consultation: 6CCVD’s in-house PhD team can assist with material selection, surface termination (hydrogen or oxygen), and optimizing BDD parameters for similar voltammetric sensing projects in food safety, biological fluids, or drug analysis.
  • Secure and Reliable Shipping: We provide global shipping (DDU default, DDP available) for sensitive research materials, ensuring rapid and secure delivery worldwide.

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

View Original Abstract

A boron-doped diamond electrode was used as an electrochemical sensor for the determination of phlorizin (aka phloridzin, phlorrhizin) using square wave voltammetry (SWV). Phlorizin (Phl) exhibited a well-defined oxidation peak at +0.9 V (versus Ag/AgCl electrode 3 M KCl) in solutions with a pH value of 6.0. Parameters such as pH value and scan rate were optimized for cyclic voltammetry as well as amplitude and frequency for SWV. The sensor gave excellent response with a wide linear dynamic range for concentrations of phlorizin from 3 to 100 mu M with a detection limit of 0.23 mu M and a good repeatability (+/- 0.9%, n = 7 measurements, c = 10 mu M). The effect of interferences by most common compounds was tested, and the method was successfully applied to the determination of the title compound in apple root extracts and urine samples with satisfactory recovery.