Identity is a separate question from potency. A 95% curcuminoid extract can be the right plant, the wrong plant part, or a mixture designed to hit the marker. TLC and macroscopic or organoleptic checks are the first line of defense against a material that is chemically plausible but botanically wrong.
How the method works
A sample is spotted on a silica plate and developed in a solvent system. Compounds migrate different distances according to their polarity, producing a pattern of spots. Under UV light or after a derivatization spray, the pattern can be compared with a reference standard or a authenticated reference material.
TLC is inexpensive and visual, which makes it useful for screening and for documenting a fingerprint. It is not a precise quantification method, and it depends heavily on the reference material and the analyst's interpretation.
What it can prove
- That the sample's chromatographic pattern is consistent with a reference material.
- That a gross substitution or adulteration may be present if the pattern differs.
- A documented identity check for the batch file.
Where it stops
- Qualitative or semi-quantitative, not a potency assay.
- Cannot prove the plant part on its own.
- Cannot detect every possible adulterant.
What identity testing should include
A useful identity package combines the botanical name, plant part, a macroscopic description, and a chromatographic fingerprint. For powdered extracts, a microscopy or DNA-based check may be more appropriate. For high-value botanicals, an authenticity test — isotope, DNA, or marker-profile analysis — can be added.
The identity result should be lot-specific. A generic 'identity: complies' statement without a reference or a method is not enough to support a supplier qualification file.
Reading the result on a COA
- Check the reference material and solvent system.
- Ask for the plate image or a description of the fingerprint.
- Combine with a marker assay and, where needed, an authenticity test.
What to ask a supplier
What reference material was used for the identity comparison?
Can you provide the TLC image or fingerprint description?
Do you recommend an authenticity test for this botanical?
Related terms
References and further reading
External links are provided for orientation. Methods, limits, and acceptance criteria differ by market and product; confirm the applicable requirements with your regulatory advisor.
Cite this page
Rainwood Botanical. "Thin-layer chromatography and identity testing for botanical extracts." October 2026. https://ingredients.rainwoodbio.com/resources/methods/tlc-identity/