In analytical chemistry, scientists use different techniques to identify and measure substances. Here are the common ones, grouped simply:
1. Gravimetric Techniques
- What it does: Measures the amount of a substance by weighing it after converting it to a pure, solid form.
- Example: Precipitation gravimetry (forming a solid from a solution).
2. Volumetric (Titration) Techniques
- What it does: Measures the amount of substance by reacting it with a solution of known concentration.
- Example: Acid-base titration, redox titration.
3. Spectroscopic Techniques
- What it does: Uses light or electromagnetic radiation to study substances.
- Examples:
- UV-Visible Spectroscopy (measures absorption of light)
- Infrared (IR) Spectroscopy (studies bonds in molecules)
- Atomic Absorption Spectroscopy (AAS) (detects metals)
4. Chromatographic Techniques
- What it does: Separates components of a mixture to identify or measure them.
- Examples:
- Gas Chromatography (GC)
- High-Performance Liquid Chromatography (HPLC)
- Thin-Layer Chromatography (TLC)
5. Electrochemical Techniques
- What it does: Measures electric properties (voltage, current) to study substances.
- Examples:
- Potentiometry (e.g., pH measurement)
- Voltammetry
- Conductometry
6. Mass Spectrometry (MS)
- What it does: Measures the mass of particles to identify substances and their structure.
7. Thermal Analysis
- What it does: Measures how a substance changes with temperature.
- Examples:
- Thermogravimetric Analysis (TGA)
- Differential Scanning Calorimetry (DSC)
Summary:
Analytical chemistry techniques are mainly about finding what is there (qualitative) and how much is there (quantitative). Techniques like gravimetric and titration are classical, while spectroscopy, chromatography, and mass spectrometry are modern methods.