Quantitative scattering of melanin solutions
Jennifer J Riesz 1, Joel B Gilmore 1 and Paul Meredith 2*
1 University of Queensland
2 The University of Queensland
* To whom correspondence should be addressed. E-mail: meredith{at}physics.uq.edu.au.
Submitted on October 11, 2005
Revised on December 12, 2005
Accepted on 15 February 2006
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Abstract |
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The optical scattering coefficient of a dilute, well solubilised eumelanin solution has been accurately measured as a function of incident wavelength, and found to contribute less than 6% of the total optical attenuation between 210 and 325nm. At longer wavelengths (325nm to 800nm) the scattering was less than the minimum sensitivity of our instrument. This indicates that UV and visible optical density spectra can be interpreted as true absorption with a high degree of confidence. The scattering coefficient vs wavelength was found to be consistent with Rayleigh Theory for a particle radius of 38±nm. Our results shed important light on the role of melanins as photoprotectants.
Key Words:
absorption, eumelanin, melanin, optical attenuation, optical density, scattering
