Spectroscopy helps in qualitative analysis by identifying the elements, ions, or compounds present in a sample based on how they interact with electromagnetic radiation (light).
Here’s how it works :
- Each substance has a unique spectrum — When light interacts with matter, atoms or molecules absorb or emit light at specific wavelengths. This pattern acts like a “fingerprint” for that substance.
- Detection of elements or compounds — By studying the wavelengths or colors of light absorbed or emitted, scientists can determine which elements or compounds are present.
- Types of spectroscopy used:
- Atomic absorption spectroscopy (AAS): Identifies metal ions by their light absorption.
- Emission spectroscopy: Detects elements based on the light they emit when excited.
- Infrared (IR) spectroscopy: Identifies organic compounds by their molecular vibrations.
- Ultraviolet-visible (UV-Vis) spectroscopy: Reveals information about conjugated systems and ions.
- No need for large samples: Only a small amount of material is needed for identification.
In short: Spectroscopy helps in qualitative analysis by providing a quick, accurate, and non-destructive way to identify the chemical composition of unknown substances based on their unique light spectra.