this question is messing with my mind I have read alot of literature related to formation synthesis of nanoparticles either with chemical or green methods. I both synthesis methods i see that U-vis sopectroscopy seems to be only Qualitative techniques that confirms the formation of nanoparticles of specific metal with a characteristic peak lamda max. while all other techniques like xrd, sem,Dls,tem,xrd,zeta-sizer tell about crystallinity,shap,size,surface morphology etc. they dont tell that they are the nanoparticles of that material etc.. even IR dont confirm exactly about metallic formation...! which is the technique other than Uv-vis spectro that tells qualitatively about nanoparticles??
UV is not always informative, Au, Ag and Cu NPs give Localized SPR in visible region, but SPR for other metal NPs is not always informative neither it fall in visible region. It depends on situation, all the techniques are linked with each other to built a complete picture. XRF, TEM and EDX give good maping of NPs.
EDS attached to the SEM is a suitable technique that confirm formation of metal nanoparticles either qualitatively and quantitatively. EDS mapping provides images of elemental distributions.
Electron microscopy (number distribution) and DLS (intensity distribution) are probably the best combination of techniques for sizing in the sub-100 nm region. SAXS also can be used. ESCA/XPS (or Auger) will confirm the oxidation state of the species on the surface. Be aware that, in air, all surface (5 - 10 atomic layers) species will be fully oxidized (plus a high proportion of carbon) and that for systems containing more than one component, there will be chemisorption induced segregation of one component in preference to another so that the surface and bulk compositions will always be different. One example is 'colloidal silver' which is actually silver oxide on the surface (and it's the Ag+ that's active as a bactericide. See:
Nov 11th, 2008. Dispersion and nanotechnology http://tinyurl.com/hpywsge
and: September 2nd, 2015 Silver colloids and invisible ink
https://www.brainshark.com/malvern/vu?pi=560497681&b=1&tx=120486&c1=22
UV is not always informative, Au, Ag and Cu NPs give Localized SPR in visible region, but SPR for other metal NPs is not always informative neither it fall in visible region. It depends on situation, all the techniques are linked with each other to built a complete picture. XRF, TEM and EDX give good maping of NPs.
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