Graduate
  1. Physical Chemistry  1.1. Thermodynamics  1.1.1. Laws of Thermodynamics  1.1.2. Enthalpy and heat capacity  1.1.3. Entropy and free energy  1.1.4. Phase Equilibrium  1.1.5. Statistical thermodynamics  1.1.6. Thermodynamic cycle  1.1.7. Fugacity and activity  1.2. Quantum Chemistry  1.2.1. Principles of quantum mechanics  1.2.2. Schrödinger Equation  1.2.3. Particle in a box  1.2.4. Operators and eigenvalues  1.2.5. Atomic orbitals  1.2.6. Molecular orbital theory  1.2.7. Perturbation theory  1.2.8. Valence bond theory  1.2.9. Hybridization and chemical bonding  1.3. Chemical kinetics  1.3.1. Rate laws and reaction mechanisms  1.3.2. Collision theory  1.3.3. Transition state theory  1.3.4. Enzyme Kinetics  1.3.5. Chain Reactions and Polymerization  1.3.6. Photochemical reactions  1.4. Statistical mechanics  1.4.1. Partitioning functions  1.4.2. Molecular distribution functions  1.4.3. Boltzmann Distribution  1.4.4. Bose–Einstein and Fermi–Dirac statistics  1.5. Spectroscopy  1.5.1. Rotational Spectroscopy  1.5.2. Vibrational Spectroscopy  1.5.3. Electronic Spectroscopy  1.5.4. Nuclear magnetic resonance spectroscopy  1.5.5. Mass Spectrometry  1.5.6. Raman Spectroscopy  1.5.7. Electron paramagnetic resonance spectroscopy  1.6. Surface and colloidal chemistry  1.6.1. Absorption isotherm  1.6.2. Surface tension and wetting  1.6.3. Colloidal Stability  1.6.4. Catalysis  1.6.5. Emulsions and micelles  1.7. Electrochemistry  1.7.1. Nernst equation  1.7.2. Electrochemical cells  1.7.3. Conductivity and mobility  1.7.4. War  1.7.5. Fuel cells  1.7.6. Electrolysis
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic reactions  2.2. Spectroscopy and structural determination  2.2.1. UV-Vis Spectroscopy  2.2.2. IR Spectroscopy  2.2.3. NMR Spectroscopy  2.2.4. Mass Spectrometry  2.2.5. X-ray crystallography  2.3. Stereoscopic  2.3.1. Chirality and optical activity  2.3.2. Structural analysis  2.3.3. Geometrical isomerism  2.3.4. Dynamic Stereochemistry  2.4. Organometallic Chemistry  2.4.1. Organolithium and organomagnesium reagents  2.4.2. Palladium-catalyzed cross-coupling reactions  2.4.3. Transition Metal Complexes  2.4.4. Metal–carbon bond  2.5. Polymer chemistry  2.5.1. Polymerization mechanism  2.5.2. Polymer Characteristics  2.5.3. Biodegradable Polymer  2.5.4. Conducting polymer  2.5.5. Supramolecular polymers  2.6. Medicinal chemistry  2.6.1. Drug design and development  2.6.2. Pharmacokinetics and pharmacodynamics  2.6.3. Structure-activity relationships  2.6.4. Molecular docking and drug screening
  3. Inorganic chemistry  3.1. Coordination chemistry  3.1.1. Crystal field theory  3.1.2. Ligand field theory  3.1.3. Spectrochemical Series  3.1.4. Chelation and stability  3.2. Organometallic Chemistry  3.2.1. Metal Carbonyls  3.2.2. Catalysis by organometallic complexes  3.2.3. Metallocenes  3.3. Bio-inorganic chemistry  3.3.1. Metalloproteins and enzymes  3.3.2. The role of metals in biological systems  3.3.3. Metal ion transport and storage  3.4. Solid state chemistry  3.4.1. Crystal Structures  3.4.2. Band theory of solids  3.4.3. Superconductors  3.4.4. Defects in the crystal  3.5. Lanthanides and Actinides  3.5.1. Electronic configuration in lanthanides and actinides  3.5.2. Coordination chemistry of the lanthanides  3.5.3. Magnetic Properties of Lanthanides
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.2. Spectroscopic Techniques  4.2.1. Atomic absorption spectroscopy  4.2.2. X-ray diffraction  4.2.3. Inductively coupled plasma spectroscopy  4.3. Electroanalytical methods  4.3.1. Potentiometry  4.3.2. Voltammetry  4.3.3. Colometry  4.4. Mass Spectrometry  4.4.1. Ionization Technique  4.4.2. Fragmentation Pattern  4.5. Chemometrics  4.5.1. Multidisciplinary analysis  4.5.2. Machine Learning in Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.1.1. Force fields and energy minimization  5.1.2. Monte Carlo simulation in molecular dynamics simulations  5.2. Quantum chemical methods  5.2.1. Hartree–Fock theory  5.2.2. Density functional theory  5.2.3. Semi-empirical methods  5.3. Computational drug design  5.3.1. Molecular Docking  5.3.2. QSAR Modeling  5.3.3. Virtual Screening
  6. Biochemistry  6.1. Enzyme Kinetics  6.1.1. Michaelis-Menten kinetics  6.1.2. Inhibition mechanism  6.2. Metabolism and Bioenergetics  6.2.1. Glycolysis  6.2.2. Citric acid cycle  6.2.3. Electron transport chain  6.3. molecular Biology  6.3.1. DNA replication and repair  6.3.2. Protein synthesis  6.3.3. Gene Regulation  6.4. Structural Biochemistry  6.4.1. Protein Folding  6.4.2. Membrane Biophysics
  7. Environmental Chemistry  7.1. Atmospheric Chemistry  7.1.1. Greenhouse gases  7.1.2. Ozone depletion  7.1.3. Air pollutants and smoke  7.2. Water Chemistry  7.2.1. pH and water hardness  7.2.2. Wastewater treatment  7.2.3. Aquatic Chemistry  7.3. Soil Chemistry  7.3.1. Heavy metal contamination  7.3.2. Soil pH and Buffering  7.3.3. Nutrient cycling  7.4. Toxicology and Chemical Safety  7.4.1. Toxicokinetics  7.4.2. Risk Assessment in Toxicology and Chemical Safety in Environmental Chemistry  7.4.3. Effects of pollutants on the environment

Graduate → Analytical chemistry → Electroanalytical methods ↓


Voltammetry


Voltammetry is an essential electroanalytical technique used to study redox processes in analytical chemistry. It involves measuring current as a function of applied potential. This technique provides information about the kinetics of electron transfer reactions as well as the concentration of the analyte. There are several types of voltammetry, each with its own unique approach and application.

Fundamentals of voltammetry

The basic concept of voltammetry is based on controlling the potential of the electrode while measuring the resulting current. The working electrode, where the reaction of interest occurs, is typically small and metals such as platinum, gold or carbon materials are used.

The usual setup of a voltammetric experiment involves three electrodes:

  • Working electrode (WE): where the main reaction occurs.
  • Reference electrode (RE): Provides a constant potential against which the potential of the working electrode is measured.
  • Counter electrode (CE): Completes the circuit in an electrolytic cell.

The measured current is directly related to the concentration of the electroactive species and provides information about the reaction kinetics at the electrode surface.

Working Electrode Reference electrode Electrolyte

Types of voltammetry

There are several types of voltammetric techniques, each suitable for specific applications. Here are some of the most common types:

Linear sweep voltammetry (LSV)

In linear sweep voltammetry, the potential is scanned linearly over time, and the resulting current is recorded. LSV is often used to study the redox properties of chemical species.

E = E0 + (scan rate) x time

As the potential is spread, a graph of potential versus current is produced, showing peak currents corresponding to the reduction or oxidation of the species in solution.

Cyclic voltammetry (CV)

Cyclic voltammetry involves the application of a triangular waveform of potential between two set values. The forward sweep reduces the species, while the reverse sweep oxidizes the reduction product. The resulting data provide a characteristic peak shape, which is diagnostic for electrochemical systems. CV is one of the most versatile and widely used techniques in voltammetry.

Reverse Sweep Forward Sweep Possibility Current

The points in the cyclic voltammogram indicate the potentials at which oxidation or reduction occurs, and the peak height is an indication of the concentration of the analyte.

Polarography

One of the earliest forms of voltammetry, polarography, involves using a falling mercury electrode (DME) as the working electrode. When the mercury falls from the capillary, it promotes fresh, regenerated electrode surfaces. This approach has been widely used in the analysis of metal ions.

Applications of voltammetry

Voltammetry has many applications in different fields. Here are some examples:

Environmental analysis: Voltammetry is used to analyze trace metals and organic pollutants in water and soil samples. For example, it can help measure lead (Pb2+) levels in water.

Biological analysis: It is used to study biomolecules such as proteins and DNA. For example, cyclic voltammetry can be used to observe the oxidation of ascorbic acid in biological samples.

Benefits and limitations

Although voltammetry provides valuable information, it is important to understand its advantages and limitations.

Benefit

  • Highly sensitive and capable of detecting low concentrations of analytes.
  • Provides both qualitative and quantitative data.
  • Versatile in terms of different types of electrochemical studies with variations like CV, LSV etc.

Boundaries

  • Interference from other electroactive species can affect the accuracy of the results.
  • Proper calibration and experimental setup are required to ensure accurate results.
  • Complex data interpretation, especially in systems with multiple electroactive species.

Conclusion

Voltammetry remains a powerful electroanalytical technique that has wide applications in research, industry, and quality control. Understanding its principles and various methods provides valuable insights into the electrochemical properties of substances, impacting fields ranging from environmental science to biochemistry. With its flexibility and high sensitivity, voltammetry remains an essential tool in the chemist's toolkit.


Graduate → 4.3.2


U
username
0%
completed in Graduate

← Prev (4.3.1)
Potentiometry
Next (4.3.3) →
Colometry

Comments 



Voltammetry

https://www.chemistryelite.com/g/4.3.2?ceal=en