does not correspond to the reference spectra. Although there
is some resemblance of the AgNPs spectrum with that from
silver foil, the energy offset of Ag L2,3 edge of nanoparticles
and the Ag foil is not the same. There is also a more
pronounced peak denoted by dot-dash line (see fig 2) which
is not present for Ag foil, so there is additional chemical
bonding to the silver present in the AgNPs within the sea
urchin. Thus, the agglomerated AgNPs are unlikely to be
composed of a single stoichiometric compound.
Comparing the XANES spectrum across the Ag L2,3 edge
(fig. 3) from the AgNP exposed sea urchin (red) with the
spectrum of AgNPs within Lolium multiflorum plants (black)
(taken from Yin et al., 2011), it is observed that the lowest
energy peak of both spectra is similar. This peak is assigned
to oxidized Ag species complexed with S and O/N ligands (Yin
et al., 2011). Therefore, the agglomerated AgNPs in sea
urchins are likely to contain similar compounds of silver, as
observed by Yin et al. (2011).