PHD
  1. Inorganic chemistry  1.1. Coordination chemistry  1.1.1. Ligand field theory  1.1.2. Crystal field theory  1.1.3. Molecular Orbital Theory for Coordination Compounds  1.1.4. Stability of Coordination Compounds  1.1.5. Electronic spectra of coordination compounds  1.1.6. Isomerism in Coordination Compounds  1.1.7. Kinetics and mechanism of coordination reactions  1.2. Organometallic Chemistry  1.2.1. Metal Carbonyls  1.2.2. Metal alkyl and aryl  1.2.3. Fischer and Schrock carbonaceans  1.2.4. Oxidative Addition and Reductive Elimination  1.2.5. Metal Hydrides  1.2.6. Catalysis by organometallic compounds  1.2.7. Metallocenes and Sandwich Complexes  1.2.8. CH activation  1.3. Solid state chemistry  1.3.1. Crystal structures and lattices  1.3.2. Band theory and electrical properties  1.3.3. Defects in the crystal  1.3.4. Synthesis of solid state materials  1.3.5. Magnetic and optical properties of solids  1.3.6. Superconductivity  1.3.7. Solid state ionics  1.4. Bio-inorganic chemistry  1.4.1. Metalloproteins and enzymes  1.4.2. Metal ion transport and storage  1.4.3. The role of metals in medicine  1.4.4. Bioinspired catalysis  1.4.5. Metal–DNA interactions  1.4.6. Metal Complexes in Medical Science  1.5. Lanthanides and Actinides  1.5.1. Electronic configuration and oxidation states in lanthanides and actinides  1.5.2. Spectral and Magnetic Properties in Lanthanides and Actinides  1.5.3. Separation and Extraction of Lanthanides and Actinides  1.5.4. Coordination chemistry of f-block elements  1.6. Main Group Chemistry  1.6.1. Chemistry of boron compounds  1.6.2. Chemistry of Silicon and Germanium Compounds  1.6.3. Chemistry of Phosphorus and Sulfur Compounds  1.6.4. Organosilicon chemistry  1.6.5. Noble Gas Chemistry
  2. Organic chemistry  2.1. Reaction mechanism  2.1.1. Nucleophilic substitution reactions  2.1.2. Electrophilic addition and substitution reactions  2.1.3. Elimination reactions  2.1.4. Rearrangement reactions  2.1.5. Radical reactions  2.1.6. Pericyclic Reactions  2.1.7. Photochemical reactions  2.2. Stereoscopic  2.2.1. Chirality and optical activity  2.2.2. Structural analysis  2.2.3. Stereoelectronic effects  2.2.4. Asymmetric synthesis  2.2.5. Dynamic Stereochemistry  2.3. Organometallic Chemistry in Organic Synthesis  2.3.1. Organolithium and organomagnesium reagents  2.3.2. Transition metal catalyzed coupling reactions  2.3.3. Palladium-catalyzed reactions  2.3.4. Olefin Metathesis  2.3.5. Gold and silver catalysis  2.4. Natural products chemistry  2.4.1. Alkaloids and terpenoids  2.4.2. Steroids and Flavonoids  2.4.3. Total synthesis of natural products  2.4.4. Biosynthesis of natural products  2.5. Supramolecular Chemistry  2.5.1. Host-Guest Chemistry  2.5.2. Self-assembly and molecular recognition  2.5.3. Supramolecular Catalysis  2.5.4. Molecular Machines
  3. Physical Chemistry  3.1. Thermodynamics  3.1.1. Laws of Thermodynamics  3.1.2. Chemical Potential and Equilibrium  3.1.3. Statistical thermodynamics  3.1.4. Non-equilibrium thermodynamics  3.2. Quantum Chemistry  3.2.1. Schrödinger equation and its applications  3.2.2. Molecular orbital theory  3.2.3. Density functional theory  3.2.4. Post-Hartree–Fock methods  3.3. Chemical kinetics  3.3.1. Reaction rate theory  3.3.2. Mechanism and rate laws  3.3.3. Catalysis and enzyme kinetics  3.3.4. Reaction dynamics  3.4. Spectroscopy and molecular structure  3.4.1. Infrared Spectroscopy  3.4.2. UV-visible spectroscopy  3.4.3. Nuclear Magnetic Resonance Spectroscopy  3.4.4. Mass Spectrometry  3.4.5. Raman Spectroscopy  3.5. Surface and Colloid Chemistry  3.5.1. Absorption and Catalysis  3.5.2. Surfactants and micelles  3.5.3. Colloidal Stability  3.5.4. Nanomaterials and Interfaces
  4. Analytical chemistry  4.1. Chromatography  4.1.1. Gas Chromatography  4.1.2. High Performance Liquid Chromatography  4.1.3. Thin Layer Chromatography  4.1.4. Ion Chromatography  4.2. Electroanalytical techniques  4.2.1. Voltammetry and Polarography  4.2.2. Conductometry and potentiometry  4.2.3. Colometry  4.3. Spectroscopic Methods  4.3.1. Atomic absorption spectroscopy  4.3.2. Fluorescence Spectroscopy  4.3.3. X-ray diffraction  4.3.4. Electron paramagnetic resonance spectroscopy  4.4. Chemometrics  4.4.1. Data processing and statistical methods  4.4.2. Multidisciplinary analysis  4.4.3. Machine Learning in Analytical Chemistry
  5. Theoretical and Computational Chemistry  5.1. Molecular dynamics simulation  5.2. Quantum chemistry methods  5.3. Computational drug design  5.4. Machine Learning in Chemistry  5.5. Ab initio molecular dynamics
  6. Biophysics and Medicinal Chemistry  6.1. Drug discovery and design  6.2. Enzyme kinetics and inhibition  6.3. Chemical biology approach  6.4. Protein-ligand interactions  6.5. Bioorthogonal chemistry
  7. Materials chemistry  7.1. Polymer chemistry  7.1.1. Polymerization mechanism  7.1.2. Functional Polymers  7.1.3. Biodegradable Polymer  7.1.4. Conducting and semiconducting polymers  7.2. Nano Chemistry  7.2.1. Nanoparticles and nanostructures  7.2.2. Carbon-based nanomaterials  7.2.3. Quantum dots  7.3. Energy and Environmental Chemistry  7.3.1. Battery and Fuel Cell Chemistry  7.3.2. Green chemistry and sustainable materials  7.3.3. Photocatalysis

PHD → Analytical chemistry ↓


Electroanalytical techniques


Electroanalytical techniques are a set of methods used in chemistry to study the movement of electrons during chemical reactions. These methods help us understand chemical processes by measuring the electrical properties of a system. In the field of chemistry, especially analytical chemistry, these techniques provide valuable information about the structure, concentration, and properties of various substances.

Electrochemical techniques are usually classified into several categories based on the electrical quantity measured, such as current, potential, impedance or charge. The main electroanalytical techniques include potentiometry, voltammetry and amperometry, etc. In this explanation, we will go through each of these techniques in detail, exploring their principles, applications and advantages.

1. Potentiometry

Potentiometry is an electroanalytical method in which the potential difference between two electrodes is measured while ensuring that no significant current flows through the electrochemical cell. The most common example of potentiometry is the working of a pH meter, which measures the acidity or alkalinity of a solution.

In potentiometry, a reference electrode and an indicator (or working) electrode are used. The reference electrode has a constant and known potential, while the potential of the indicator electrode varies depending on the specific analyte in the solution.

E = E_ref + (RT/nF) * ln(Q)

In the above equation:

  • E is the measured potential difference.
  • E_ref is the potential of the reference electrode.
  • R is the universal gas constant.
  • T is the temperature in Kelvin.
  • n is the number of moles of transferred electrons.
  • F is the Faraday constant.
  • Q is the reaction quotient.

Potentiometry is widely used in a variety of applications due to its simplicity and cost-effectiveness. It is helpful in environmental monitoring, clinical diagnosis, and industrial quality control. For example, ion-selective electrodes can be used to directly measure specific ions such as sodium or potassium in complex matrices.

2. Voltammetry

Voltammetry is a technique in which current is measured as a function of the applied potential. The general idea is to apply a varying potential to an electrochemical cell and observe the resulting current flow behavior. This method yields information about redox reactions and can identify and quantify various substances.

A variety of voltammetry techniques, such as cyclic voltammetry, linear sweep voltammetry, and differential pulse voltammetry, are used depending on the information required. In cyclic voltammetry, the potential is swept between two values in a repeating cycle, allowing electrochemical processes to be studied over multiple cycles.

Peak current Voltage Sweep

Voltammetric techniques are important in studying reaction mechanisms and characterizing new materials. They are also important in electrodeposition and sensor development. For example, cyclic voltammetry helps to investigate the redox behavior of organic molecules and metals.

3. Amperometry

Amperometry is a method in which current is measured at a fixed potential over time. It is often used to measure the concentration of an electroactive species in a solution. According to Faraday's laws the current flowing through an electrochemical cell is directly related to the concentration of the analyte.

A typical application of amperometry is in glucose monitoring devices, where the current produced by the enzymatic reaction is proportional to the glucose concentration.

Fixed Capacity current

Amperometry's fast response time and high sensitivity make it ideal for real-time monitoring of analytes in clinical, environmental, and industrial settings. It is particularly useful in the development of biosensors where enzymes catalyze reactions, creating a measurable current.

4. Conductometry

Conductometry measures the electrical conductivity of a solution. This technique is based on the principle that the conductivity of a solution is proportional to the concentration of ions present in it. Conductometry is often used to monitor the progress of chemical reactions and analyze the purity of substances.

This is particularly useful in titrations where a sudden change in conductivity can determine the end point. For example, in an acid-base titration, a sudden change in conductivity indicates the neutralization point.

Conductivity (κ) = 1 / Resistivity (ρ) = G * (l/A)

In the above equation:

  • G is the conductivity.
  • l is the length of the sample.
  • A is the area of the cross section.

Conductometry is widely used in water quality analysis and environmental studies to determine the concentrations of ionic species.

5. Colometry

Coulometry involves measuring the electrical charge passing through a solution to determine the amount of an analyte. It is a highly accurate quantitative analysis technique, often used for trace analysis.

The basic principle of coulometry is based on Faraday's law of electrolysis, which states that the amount of chemical change is proportional to the amount of electricity passing through the substance.

Q = n * F * mole

Where:

  • Q is the total electric charge.
  • n is the number of moles of electrons.
  • F is the Faraday constant.

Colometric methods are used mainly to determine moisture content and purity in pharmaceuticals, the food industry, and environmental analysis.

Conclusion

Electroanalytical techniques provide invaluable data about the electrochemical nature of complex systems. Using various methods such as potentiometry, voltammetry, amperometry, conductometry, and coulometry, chemists can gain a deeper understanding of the chemical and physical properties of a substance.

Each technique has its own specific strengths and is applied in specialized areas ranging from environmental monitoring to the development of sensitive biosensors. The ability to make precise measurements and analyze electrochemical reactions is vital in advancing scientific knowledge and developing new techniques. As research continues, electroanalytical techniques will undoubtedly evolve, providing even greater precision and insight into the electrifying world of chemistry.


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Electroanalytical techniques

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