A Novel Nanoparticle Concentration Measurement Method Using Atomic Force Microscope

Methods to efficiently measure the concentration of nanoparticles in liquid suspensions are extremely important in nanoparticle-based applications. Existing nanoparticle concentration measurement methods such as nanoparticle tracking analysis (NTA), single particle-inductively coupled plasma-mass spectroscopy (SP-ICP-MS) and TEM have inherent limitations, including size requirements, special physical or chemical properties and special sample preparation. This paper presents a novel method to measure the concentration of nanoparticles by atomic force microscope. Nanoparticles distribution property after complete evaporation on silicon wafer was found and particles amount estimation theory was established, which enabled accurate and efficient measurement of nanoparticles concentration. The nanoparticle suspensions with different concentration, size and type were measured by the proposed approach, respectively. The results were compared with the estimated concentration by mass fraction, which demonstrated the effectiveness and correctness of this AFM-based measurement method.