I am unable to make sense of these results , can anyone please guide me.
I incubated Cu and Ag NPs (with others) with different pH solutions and got these shifts in the uv-vis spectra. Does this shift indicate any change in shape or size of NPs or have it yielded aggregated clumps?
The over all antibacterial efficacy varied across the pretreated levels.
It looks more like aggregation of the nanoparticles that depends on charge thus - on pH
Hello! It is probably due to aggragation process. Varying the pH and depending on the stabilzer you used, you can get different UV curves and shifts like yours.
Hello. It is better if you plot these in % absorbance. Secondly, while working with UV-Vis, try to reduce absorbance to below 1. This can be done by diluting your samples which can give you absorbance in the range of 0-1. The results can then be better interpreted .
Secondly the UV-Vis peak gives you two information depending upon the composition of your nanoparticle:
1- The core (in your case Ag or Cu)
2- The Coat (depending upon the synthesis methodology you adopted)
The typical peak for Ag is near 400-450 but I do not see anything in Cu (or CuO2? ) nanoparticles. In all of your samples, there is presence of some "fingerprint" UV-Vis peaks, which leads me to think it is probably because of the "coating" and pH is changing "coating" of your nanoparticles hence you may get varying size of nanoparticles (or possibly agglomeration). Hope that helps
