Hydrophilic carbon nanoparticles (CNPs) were synthesized from amino acids using a pulsed arc discharge over an aqueous solution surface under pressurized argon at 4 MPa. The CNPs produced using this method were highly dispersible in water because their surfaces were modified by hydrophilic groups derived from the amino acids. The number of carbons in the straight chain of the source amino acids affected the generation of the CNPs, leading to different particle sizes, crystallinities, and nitrogen compositions. The oxygen content in the CNPs was independent of the source amino acid, but the nitrogen content was affected by the atomic ratio of nitrogen in the source amino acid. (C) 2016 Elsevier B.V. All rights reserved.