Hi Pasquale, you need to use X Ray Energy Dispersive Spectrometer to find inorganics. EDS will provide you a chemical elementary quantitative microanalysis, depending of kind of EDS, you can detect after chenical element B. This device may be is instaled in your Scanning Electron Microscope.

Since you are not getting expert opinions you may want to give us some specifics of your task.

Just a reminder: ESEM cannot replace bulk chemical analysis when trace elements/contaminants are of interest.

Thank to both for availability in answer me. I'm not an expert of ESEM but actually we have a really dramatic safety issue related to vaccines because of a chemist who address the presence of metallic nanoparticles in some vaccine vial (but he didn't published any data). He talk about 60-80 nm particles of various metals. So I asked here expert opinion in order to obtain subsequent information: are liquid vaccine evaluable with ESEM? Which are the technical requirements of a correct analysis? Is ESEM the best option to reveal contaminants nanoparticles in liquid vaccines? Thank you in advance if you answer me. I'm also trying to collect some material of this research...

If you put a liquid in an ESEM you'll see only surface of this liquid, it is not transparent for electrons, which is mostly useless for you. You can try to put a drop of vaccine on some smooth substrate which does not contain elements heavier than O (such as polyethylene - HDPE, LDPE, etc.) and air dry it. Coat with carbon. Observe in a standard SEM mode. Backscattered detector and EDS should help you. Do not know if SEM is the best method for you. 

Thank you, Vladimir..so, an ESEM analysis of liquid vaccine in order to evaluate metallic contaminants is not the best option (as I suppose). We don't know the applied methodology by the above mentioned chemist who address the presence of metallic nanoparticles in some vaccine vial since he didn't published any data. Is it possible that, beyond a fake research, he  substantially observed environmental contaminants of the samples?

I do not think we can successfully discuss some unknown results obtained with unknown protocol.

Dear Vladimir, the chemist published his data in an open access journal. May I ask you to take a look to the article, please? Just to have an expert opinion on methodology. Thank you in advance.

Methodology is OK. There were no liquid phase, so things were as usual.

By the way, in any specimen you can find some contamination. I never worked with vaccines, but, say, in cell cultures I've seen all kinds of particles, from stainless steel to antimony. Problem is  not a finding a particle, but in quantifying results. Stray particles could be found anywhere. 

Really thank you, Vladimir for these precious information. I'm aware that the lack of controls (other medicinal products in liquid solution or in pre-filled syringe) cannot exclude contamination by the vials and that ESEM don't permit quantitative analysis. But I have almost another unresolved doubt: is it possible that this methodology promotes the nanoparticles formation, i.e. facilitate ion precipitation and impurities aggregation?

Moreover, SiAl and SiAl+Fe or Mg are present in every sample. May this be due to a possible contamination?