What should be the conductivity and pH value for the sample and how to adjust them?
The conductivity for aqueous solutions should be around 0.2 S/m. The pH value is unimportant for electrospray operation itself, but it may be very important in getting results. This is determined by specific characteristics of the sample. For example, for proteins, the pH should be above the isoelectric point (pI) of the protein, generally, to prevent the adherence of the protein to the silica capillary tube wall. But for zirconium oxide nanoparticles, use of a basic pH will result in gel formation and capillary blockage, even at very low concentrations. For sucrose which sometimes is used to generate nanometer-sized aggregates, the pH does not seem to be important. You need to know the chemistry of your sample.
