Quantitative scattering of melanin solutions.
The optical scattering coefficient of a dilute, well-solubilized eumelanin solution has been accurately measured as a function of incident wavelength, and found to contribute <6% of the total optical attenuation between 210 and 325 nm. At longer wavelengths (325-800 nm), the scattering was less than the minimum sensitivity of our instrument. This indicates that ultraviolet and visible optical density spectra can be interpreted as true absorption with a high degree of confidence. The scattering coefficient versus wavelength was found to be consistent with Rayleigh theory for a particle radius of 38 +/- 1 nm. Our results shed important light on the role of melanins as photoprotectants.
Riesz
Jennifer
J
Soft Condensed Matter Physics Group, Condensed Matter Theory Group, Physics Department, University of Queensland, St. Lucia, Brisbane, Australia, QLD 4072. riesz@physics.uq.edu.au
Gilmore
Joel
J
Meredith
Paul
P
D008027:Light; D008543:Melanins / Q000737:chemistry*; D008962:Models, Theoretical; D012542:Scattering, Radiation; D012996:Solutions / Q000737:chemistry; D013057:Spectrum Analysis
D008543:Melanins; D012996:Solutions; C041877:eumelanin