X-RAY CHARACTERIZATION OF MELANINS .1.
X-RAY CHARACTERIZATION OF MELANINS .1.
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DOI：
10.1111/j.1600-0749.1994.tb00060.x
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发表时间：
1994-08-01
期刊：
影响因子：
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通讯作者：
ZSCHACK, P
中科院分区：
文献类型：
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作者：
CHENG, J;MOSS, SC;ZSCHACK, P
The intrinsic local structure characterization of natural sepia melanin and L-dopa and tyrosine synthetic melanin powder has been carried out by X-ray diffraction using synchrotron radiation. The derived structure factor, S(q), shows six significant diffuse peaks within the q-range from 0.3 Angstrom(-1) to 16 Angstrom(-1) in the reciprocal space (q = (4 pi sin theta)/lambda, 2 theta is the scattering angle). The Fourier transform of S(q), which yields the radial distribution function (RDF), gives us information in real space of a 1.42 Angstrom distance averaged over the C-C, C-O and C-N bond lengths as well as peaks at 2.40-2.41 Angstrom, 3.67-3.71 Angstrom and 4.67-4.70 Angstrom discrete neighbor distances. There is a great similarity in the scattering intensity profiles of the natural and synthetic melanins indicating that the synthetically prepared material may be essentially similar to ''real'' melanin in its local atomic arrangements. An evidence of a prepeak at q similar or equal to 0.45 Angstrom(-1) has been confirmed which indicates a preferred length scale of similar to 13-20 Angstrom that corresponds to the initial particle size in colloidal melanin solutions.
