1. Organoleptic Evaluation

Principle: Assessment of sensory properties, including aroma and flavor, through smell and taste.

Application: Initial qualitative evaluation of essential oil characteristics.

2. Physical Characteristics

Color and Appearance:

Principle: Visual inspection for color variations and overall appearance.

Application: Helps identify impurities or alterations in the essential oil.

Specific Gravity:

Principle: Determination of the essential oil’s density compared to water’s density.

Application: Useful for assessing purity and detecting adulteration.

3. Refractive Index

Principle: Measurement of the bending of light as it passes through the essential oil.

Application: Helps identify and differentiate essential oils based on their refractive properties.

4. Solubility Tests

Principle: Dissolving the essential oil in different solvents to assess its solubility characteristics.

Application: Provides information on the oil’s composition and potential adulteration.

5. Chemical Tests

Saponification Value:

Principle: Determination of the amount of potassium hydroxide required to saponify a specific quantity of essential oil.

Application: Indicates the presence of esters in the oil.

Ester Value:

Principle: Measurement of the amount of esters present in the essential oil.

Application: Useful for identifying and quantifying esters, common components in many essential oils.

6. Gas Chromatography (GC)

Principle: Separation of individual components of the essential oil based on their volatility.

Application: Precise quantitative and qualitative analysis of the oil’s chemical composition.

7. Mass Spectrometry (MS)

Principle: Identification of compounds in the essential oil based on their mass-to-charge ratio.

Application: Provides detailed information on individual components, aiding in identifying specific compounds.

8. Fourier Transform Infrared Spectroscopy (FTIR)

Principle: Measurement of the absorption of infrared radiation by functional groups in the essential oil.

Application: Identification of specific functional groups, aiding in the characterization of the oil.

9. Thin-Layer Chromatography (TLC)

Principle: Separation of components on a thin layer of adsorbent material.

Application: Qualitative analysis and comparison of essential oil components.

10. NMR Spectroscopy

Principle: Measurement of nuclear magnetic resonance signals to determine the structure of compounds in the essential oil.

Application: Structural elucidation of complex compounds.

11. Sensory Evaluation

Principle: Evaluation by trained sensory panels to assess the overall aroma and flavor profile.

Application: Important for quality control and ensuring the essential oil meets industry standards.

12. Regulatory Compliance

Principle: Comparison of test results with established standards and regulations. Application: Ensures that the essential oil meets legal and safety requirements.