I want to analyze my nanoparticles, which are highly dispersed in water, with the help of XPS. Please share your experience with me, if someone has knowledge of interpretation, please share it too.
I agree with the previous answer. Only a brief comment respect the option or possibility to measure a liquid sample on XPS system.
Measure liquid sample in XPS is possible .The main limitation (already mentioned ) for the liquid sample is the Ultra High Vacuum enviroment and the need to prevent or avoid significant outgassing. Since the liquid in these vacuum conditions will evaporate suddenly we need to freeze the sample to avoid the evaporation.
The liquid nitrogen is used to freeze the liquid. There are XPS systems (usually the multitechnique systems) equipped with liquid nitrogen cooled cryostage, that allow measure liquid samples. Over time this is not an uncommon option.
Right. The main problem is the vacuum. I did as Justin proposed.
The solution to use a cooling system down to solidification temperature of liguid is another possibility. But I am wondiring if the binding energies in XPS are the same at room temperature and at low temperature (LN2 for exemple)?
Just try to use Rigaku MiniCarry or UltraCarry absorption plate for liquids, and I think it will be possible to apply XPS for analysing the liquid. Rigaku offered their CarryTM system for XRF study of liquids (without extra cooling or what so ever), but I think it is the possibility to apply their system for XPS also. Because XRF analysis is also performed in vacuum. Please have a look their web-site or contact their specialist for details. They have a very good studying center in Ettlingen, Germany (Rigaku Europe).
we can analysis the nanoparticles by XPS after coating the nanoparticles over the substrate either glass or Silicon wafer or some other substrates. I too successfully used silicon wafer as substrate for the analysis. The surface electron may escape from 0 nm to several nanometers depth after X-Rays fall on the thin film of nanoparticles.
If you need to know the chemical composition of your nanoparticles surface in water, you can use cryogenic XPS with fast-frozen samples, the technique developed in our lab. You'll just need to centrifuge your suspension to make a precipitate, pour out the supernatant, and use resulting wet paste as a sample to be fast-frozen in spectrometer air-lock by liquid nitrogen. You can find detailed description of sample preparation and analysis (conventional Kratos Axis Ultra DLD spectrometer equipped with freezing facility in air-lock) in one of our papers, e.g. J. Phys. Chem. C 2007, 111, 18307-18316.