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Updated: Oct 23, 2025
A Filter-based Surface Enhanced Raman Spectroscopic Assay for Rapid Detection of Chemical Contaminants
Published on: February 19, 2016
Carminic Acid Based Red Dye from Scale Insects Detected in Red Ruby-Crowned Kinglet Feathers by Surface-Enhanced
Xuanyi Wu1,2, Santiago Sanchez-Cortes3, Ioanna Kakoulli1,2
1Department of Materials Science and Engineering, University of California, Los Angeles (UCLA), 410 Westwood Plaza, Los Angeles, CA, USA.
Abstract:
In most birds, red feather color is linked to diet and attributed to carotenoids contained in plants and fruits. In the red crown feathers of the Ruby-crowned Kinglet (Regulus calendula), a new biopigment was identified based on carminic acid, the main coloring compound of cochineal (Dactylopius coccus) and other scale insects. This has revealed a potential new class of carminic acid-based biopigments, not previously identified in feathers. In this research, red crown feathers of a Ruby-crowned Kinglet were analyzed by surface-enhanced Raman scattering (SERS) employing synthesized silver star-shaped colloids as the nanoplasmonic platform. Results indicated peaks at 450, 670, 1290-1312, 1355, 1410, 1570, 1620 cm-1 in the feather SERS spectra characteristic of carminic acid. SERS has proven to be an extremely sensitive, non-destructive technique for the identification of different feather biopigments, even at trace quantities and in the presence of other predominant coloring substances.
