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6CCVD Research

Electrochemical Evaluation of Cd, Cu, and Fe in Different Brands of Craft Beers from Quito, Ecuador

At a Glance

Section titled “At a Glance”
MetadataDetails
Publication Date2023-06-04
JournalFoods
AuthorsOscar LĂłpez-Balladares, Patricio J. Espinoza-Montero, Lenys FernĂĄndez
InstitutionsCentral University of Ecuador, Pontificia Universidad CatĂłlica del Ecuador
Citations7
AnalysisFull AI Review Included

Technical Documentation & Analysis: Boron-Doped Diamond for Trace Heavy Metal Voltammetry

Section titled “Technical Documentation & Analysis: Boron-Doped Diamond for Trace Heavy Metal Voltammetry”

Executive Summary

Section titled “Executive Summary”

This research validates the use of Boron-Doped Diamond (BDD) working electrodes coupled with Differential Pulse Anodic Stripping Voltammetry (DPASV) as a highly effective method for quantifying trace heavy metals (Cd(II), Cu(II), Fe(III)) in complex food matrices (craft beer).

  • Material Validation: The BDD electrode, characterized by SEM, exhibited optimal granular morphology (300-2000 nm microcrystals) and a low double layer capacitance (0.01412 ”F cm-2), crucial for high-sensitivity trace analysis.
  • Wide Potential Window: The BDD demonstrated a wide working potential window (-1.15 V to 1.60 V), confirming its stability and suitability for electroanalytical studies in aggressive, acidic media.
  • High Sensitivity: The DPASV method achieved excellent detection limits (DL) and quantification limits (QL), with Fe(III) quantified as low as 1.72 ”g L-1.
  • Precision and Accuracy: The method showed high reliability, reporting repeatability (RSD%) between 1.06% and 2.43% and reproducibility (RSD%) between 1.61% and 2.94%.
  • Matrix Robustness: BDD successfully handled the complex organic and alcoholic matrix of craft beer, demonstrating superior sensitivity compared to conventional methods like FAAS, particularly for Fe(III).
  • 6CCVD Value: 6CCVD specializes in manufacturing custom MPCVD BDD substrates with precise doping (3000-5000 ppm used here) and superior surface quality, directly supporting the replication and scaling of this high-performance analytical technique.

Technical Specifications

Section titled “Technical Specifications”

The following table summarizes the critical material properties and analytical performance metrics achieved using the BDD electrode in this study.

ParameterValueUnitContext
Electrode MaterialBoron-Doped Diamond (BDD)N/AWorking electrode
BDD Doping Level3000-5000ppmSpecified for the BDD substrate
Microcrystal Size Range300-2000nmVerified by Scanning Electron Microscope (SEM)
Boron/Carbon (B/C) Ratio0.052N/AAtomic ratio determined by EDS
Double Layer Capacitance (Cdl)0.01412”F cm-2Low value, indicating low sp2 content
Working Potential Window-1.15 to 1.60VIn 1 mol L-1 KCl electrolyte (pH=1)
Redox Quasireversibility (k°)2.44 x 10-2 ± 4.67 x 10-3cm s-1Standard rate constant (quasi-reversible)
Detection Limit (DL) - Fe(III)1.72”g L-1Lowest DL achieved by DPASV
Detection Limit (DL) - Cd(II)6.31”g L-1DL for Cadmium
Quantification Limit (QL) - Cu(II)5.87”g L-1QL for Copper
Repeatability (RSD%)1.06 to 2.43%High precision across all metals
Reproducibility (RSD%)1.61 to 2.94%High accuracy across all metals

Key Methodologies

Section titled “Key Methodologies”

The successful quantification of heavy metals relied on precise BDD preparation and optimized DPASV parameters:

  1. Electrode Setup: A three-electrode heart cell was utilized, featuring the BDD working electrode (0.3 cm area), an Ag/AgCl reference electrode, and a graphite rod counter electrode.
  2. Electrode Conditioning: The BDD surface was cleaned using Cyclic Voltammetry (CV) in 0.2 mol L-1 HNO3, followed by 30 conditioning cycles in 1 mol L-1 KCl (pH=1) to ensure a clean, active surface free of residual carbon impurities.
  3. Sample Digestion: Craft beer samples (25 mL) were degassed via ultrasound (30 °C, 20 min), followed by acid digestion using 65% m/m concentrated HNO3 and 30% m/m H2O2 at 100 °C until a yellow coloration was achieved.
  4. Analyte-Specific Electrolyte Selection: Optimal support electrolytes were determined for each metal to maximize signal sharpness and intensity:
    • Cd(II): 0.1 mol L-1 acetic acid/0.055 mol L-1 sodium acetate (pH 4.5).
    • Cu(II): KNO3 0.1 mol L-1/HNO3 0.1 mol L-1 (pH 1.20).
    • Fe(III): KNO3 0.1 mol L-1/HNO3 0.01 mol L-1 (pH 2.10).
  5. DPASV Parameter Optimization: Key voltammetry parameters were optimized for speed and signal definition, including Modulation Amplitude (MA), Modulation Time (MT), Time Interval (TI), Pre-concentration Potential, and Pre-concentration Time (e.g., 15 s for Cd(II) and 60 s for Cu(II)/Fe(III)).
  6. Quantification Method: Standard Addition Plot method was used to account for the significant matrix effect observed in the craft beer samples.

6CCVD Solutions & Capabilities

Section titled “6CCVD Solutions & Capabilities”

This research confirms that high-quality, precisely engineered Boron-Doped Diamond (BDD) is the enabling material for sensitive trace heavy metal analysis in complex food and beverage matrices. 6CCVD is uniquely positioned to supply the materials necessary to replicate, scale, and advance this critical electroanalytical work.

Research Requirement6CCVD Solution & Value Proposition
High-Purity BDD SubstratesTunable Doping for Optimal Performance: 6CCVD specializes in MPCVD BDD growth, offering precise control over boron doping levels (e.g., 3000 ppm used in this study, or higher/lower as required) to optimize conductivity and minimize double layer capacitance (Cdl) for ultra-trace detection.
Custom Electrode DimensionsPrecision Fabrication Services: The study utilized a 0.3 cm electrode area. 6CCVD provides custom laser cutting and shaping of BDD plates and wafers up to 125mm in diameter, ensuring exact geometric specifications for any electrochemical cell design.
Ultra-Low sp2 ContentSuperior Surface Quality: Our proprietary MPCVD growth and polishing techniques ensure minimal non-diamond carbon (sp2) impurities. This guarantees the wide potential window and low background current essential for high signal-to-noise ratios in DPASV.
Surface Finish (Granular Morphology)Advanced Polishing: We offer polishing services down to Ra < 5 nm for inch-size PCD/BDD, allowing researchers to select the optimal surface morphology (e.g., granular microcrystalline, as characterized by SEM in this paper) for maximizing active sites and enhancing stripping efficiency.
Integrated Sensor DevelopmentIn-House Metalization Capabilities: For researchers developing integrated sensors or microelectrode arrays based on this BDD platform, 6CCVD offers internal metalization services (Au, Pt, Pd, Ti, W, Cu) for reliable electrical contacts and robust device packaging.
Global Supply ChainReliable, Global Shipping: We ensure prompt, secure global delivery (DDU default, DDP available) of sensitive diamond materials, supporting international research and industrial quality control efforts.

Engineering Support

Section titled “Engineering Support”

6CCVD’s in-house team of PhD material scientists and electrochemists can provide expert consultation on material selection, doping optimization, and surface preparation protocols to ensure maximum performance for heavy metal detection and other voltammetric applications.

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

View Original Abstract

The presence of heavy metals in craft beers can endanger human health if the total metal content exceeds the exposure limits recommended by sanitary standards; in addition, they can cause damage to the quality of the beer. In this work, the concentration of Cd(II), Cu(II), and Fe(III) was determined in 13 brands of craft beer with the highest consumption in Quito, Ecuador, by differential pulse anodic stripping voltammetry (DPASV), using as boron-doped diamond (BDD) working electrode. The BDD electrode used has favorable morphological and electrochemical properties for the detection of metals such as Cd(II), Cu(II), and Fe(III). A granular morphology with microcrystals with an average size between 300 and 2000 nm could be verified for the BDD electrode using a scanning electron microscope. Double layer capacitance of the BDD electrode was 0.01412 ÎŒF cm−2, a relatively low value; Ipox/Ipred ratios were 0.99 for the potassium ferro-ferricyanide system in BDD, demonstrating that the redox process is quasi-reversible. The figures of merit for Cd(II), Cu(II), and Fe(III) were; DL of 6.31, 1.76, and 1.72 ÎŒg L−1; QL of 21.04, 5.87, and 5.72 ÎŒg L−1, repeatability of 1.06, 2.43, and 1.34%, reproducibility of 1.61, 2.94, and 1.83% and percentage of recovery of 98.18, 91.68, and 91.68%, respectively. It is concluded that the DPASV method on BDD has acceptable precision and accuracy for the quantification of Cd(II), Cu(II), and Fe(III), and it was verified that some beers did not comply with the permissible limits of food standards.

Tech Support

Section titled “Tech Support”

Original Source

Section titled “Original Source”

References

Section titled “References”
  1. 2018 - EvaluaciĂłn de las cervezas artesanales de producciĂłn nacional y su maridaje con la cocina ecuatoriana [Crossref]
  2. 2020 - Worldwide Contamination of Food-Crops with Mycotoxins: Validity of the Widely Cited ‘FAO Estimate’ of 25% [Crossref]
  3. 2019 - Hemocromatosis
  4. 2018 - El metabolismo del cobre. Sus consecuencias para la salud humana Metabolism of copper. Its consequences for human health

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