In fig. 2 the XANES spectrum from agglomerated AgNPs
in the sea urchins (bottom) is compared with reference
spectra from AgCl, Ag foil, AgNO3, Ag2O, AgO and Ag2S (Yin et
al., 2011). The data show that the edge of the spectrum from
AgNPs in the sea urchins is clearly associated with Ag,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. but