There are several methods to identify plant constituents after isolation and purification, including determining the compound class using color tests, solubility, Rf value, and spectral characteristics. Complete identification requires measuring melting point, boiling point, optical rotation, and Rf value. The most informative data comes from analyzing spectral characteristics using UV, IR, NMR, and mass spectroscopy. Final confirmation is done by comparing to authentic materials.

1. Methods of Identification
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2. Identification Methods
• In identifying a plant constituent one it has been
isolated and purified it is necessary first to
determine the class of compound (chemical
nature) and then to find out which substance it is.
• The calss of compounds is usually clear from its:
• Response to colour tests (chemical test)
• Solubility
• Rf and
• Spectral characteristics

3. • Complete identification depends on:
– Melting point (for solids)
– Boiling point (for liquids)
– Optical rotation (for optically active cpds) &
– Rf value
• The important informative data on plant
substance are its spectral characteristics.

4. Spectral Characteristics of Plant
• Ultra violte (UV)
• Infrared (IR)
• Nuclear Magnetic Resonance (NMR)
• Mass Spectroscopy
• For final confirmation direct comparison
with authentic material (if available) should
be carried out.