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


Electroanalytical methods are a set of techniques used in analytical chemistry to study materials by measuring electrical properties such as voltage, current, and charge. These methods are essential for understanding the chemical structure and properties of various substances, and have wide applications in various fields such as environmental monitoring, pharmaceuticals, and materials science.

Basic concepts

Before diving into the various electroanalytical methods, it is necessary to understand some basic concepts. Electroanalytical chemistry generally revolves around the study of ions in solution and their interactions with electrodes. It involves two primary components:

  • Electrodes: These are the conducting surfaces that facilitate the flow of electrons. Typically, these are made of materials such as platinum, gold, or carbon.
  • Electrolyte: A solvent containing ions that helps conduct electricity between electrodes.

Redox reactions

A fundamental principle in electroanalytical chemistry is the redox reaction, which consists of oxidation and reduction. Oxidation refers to the loss of electrons, while reduction is the gain of electrons. The overall reaction can be represented as:

Oxidant + ne⁻ → Reducer

In an electrochemical cell, one electrode undergoes oxidation and the other undergoes reduction.

Types of electroanalytical methods

There are many electroanalytical techniques, each with its own unique approach and application. Let's take a look at some of the most commonly used techniques:

Potentiometry

Potentiometry measures the potential difference between two electrodes without passing significant current. The most recognized application is the pH meter, which measures the acidity or alkalinity of a solution.

A typical arrangement includes a reference electrode, such as a silver/silver chloride electrode, which maintains a constant potential, and an indicator electrode, such as a glass pH electrode, which is sensitive to the ion of interest.

Example: To measure the pH of a solution:

E_cell = E_reference - E_indicator

The relationship between pH and E_cell is given by the Nernst equation:

E = E₀ - (RT/nF) * ln([H⁺])

Amperometry

Amperometry involves measuring the current flowing through an electrochemical cell at a constant potential. The current is directly related to the concentration of the analyte. This method is widely used in biosensors such as glucose sensors.

Example: In a glucose sensor, the enzyme glucose oxidase catalyzes a reaction with glucose, producing a current proportional to the glucose concentration.

Voltammetry

Voltammetry is a class of methods that apply a varying potential to an electrochemical cell and measure the current response. Various forms of voltammetry exist, such as cyclic and differential pulse voltammetry.

Cyclic voltammetry: This technique involves sweeping the potential in a cyclic manner and is particularly useful for studying redox properties.

E vs t: Varying potential I vs E: Measure current

The current-potential graph is known as cyclic voltammogram.

Coulometry

Coulometry is based on measuring the amount of electricity (in coulombs) required to completely convert a reactant in an electrochemical reaction. It is a highly accurate method used to determine the amount of a substance.

The basic theory includes the following relationships:

Q = nF

where Q is the total charge, n is the number of moles of electrons, and F is the Faraday constant.

Applications in real life

Electroanalytical methods play an important role in many areas:

  • Environmental monitoring: They are used to detect pollutants such as heavy metals in water and soil.
  • Clinical diagnosis: Blood glucose monitoring and other biosensors rely on these methods.
  • Pharmaceuticals: Electroanalytical techniques are often used in the quality control of drugs.

Benefits and limitations

Understanding the advantages and disadvantages of electroanalytical methods helps in choosing the right technique:

  • Benefit:
    • Highly sensitive and selective.
    • Capable of analyzing small sample quantities.
    • Applicable to a wide range of substances.
  • Limitations:
    • Requires careful calibration and maintenance.
    • Excessive use may cause electrode fouling.
    • Possible interference from other substances.

Future perspectives

As technology advances, electroanalytical methods are expected to become more sophisticated with advances in electrode materials, miniaturization, and automation. There is also growing interest in integrating these techniques with digital platforms, enhancing data acquisition and analysis.

Conclusion

Electroanalytical methods are indispensable tools in modern chemistry. They provide unique insights into the chemical structure and dynamics of substances. From potentiometry to coulometry, each technique offers distinct advantages and challenges that require careful consideration for effective application. Given their far-reaching implications and increasing progress, these methods will undoubtedly remain at the forefront of analytical chemistry in the years to come.


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Electroanalytical methods

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