Application of Spectroscopy play a crucial role in identifying the structure, functional groups, and composition of bioactive compounds in crude extracts.
Common techniques include:
1) UV-Vis Spectroscopy
Principle
Measures absorption of ultraviolet or visible light, typically in conjugated systems (e.g., aromatic rings, unsaturated bonds).
Application
Rapid screening for characteristic chromophores (e.g., flavonoids, alkaloids).
Preliminary quantification of known markers.
2) Infrared (IR) Spectroscopy
Principle
Detects molecular vibrations, revealing functional groups (e.g., –OH, –NH, –C=O).
Application
Confirmation of functional groups in isolated fractions.
Fingerprint region (600–1500 cm⁻¹) aids compound identification.
3) Nuclear Magnetic Resonance (NMR) Spectroscopy
Principle:
Uses magnetic fields to analyze hydrogen (¹H NMR), carbon (¹³C NMR), and other nuclei environments.
Application:
Structural elucidation of purified natural products.
Determination of stereochemistry and molecular connectivity.
4) Mass Spectrometry (MS) (Application of Spectroscopy)
Principle
Ionizes molecules and separates ions based on mass-to-charge ratio (m/z).
Application
Molecular weight determination.
Identification of characteristic fragmentation patterns.
Used with chromatographic techniques (GC-MS, LC-MS) for rapid profiling of complex mixtures.
These techniques complement each other, providing a comprehensive understanding of compound identity and purity.