Size Characterization of Ultrasmall Silver Nanoparticles Using MALDI-TOF Mass Spectrometry

Abstract

We present a rapid and reliable method to determine the sizes and size distributions of silver nanoparticles smaller than 5 nm using matrix-assisted laser desorption & ionization-time-of-flight (MALDI-TOF) mass spectrometry (MS). The MS data could be converted to size information using a simple equation derived by Cardanos formula. Calculated coefficients of size-to-mass equation were different, but the differences among the data set were negligible. Furthermore, size-to-mass equation for anisotropic particles were derived by similar process done for spherical particles. This suggests MALDI-TOF MS could be used not only for characterizing size properties, but also for characterizing shapes and sizes with high accuracy. This shows MALDI-TOF MS as useful technique in nanotechnology.