Generation of Multiply Charged Amino Acid Nanoparticles by Electrospray

Abstract

Electrospray is capable of generating functional substances as multiply charged nanoparticles and ions. It is widely used for the liquid sample introduction to mass spectrometers and air purification. In this study, particle size distribution and charge number distribution of nanoparticles of amino acids generated by electrostatic spraying were measured. The break-up process of multivalent charged droplets was estimated. The droplets immediately after spraying were break-up by the Rayleigh fission due to evaporation of the solvent. They were divided into the droplets with the particle size of about 140±80 nm and the daughter droplets of about 40±15 nm. Some of the droplets exists in an ion emission region of 10 nm or less, and single molecule ions of amino acids would be released from these microdroplets.