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Sizing by Weighing: Characterizing Sizes of Ultrasmall-Sized Iron Oxide Nanocrystals Using MALDI-TOF Mass Spectrometry
journal contribution
posted on 2013-02-20, 00:00 authored by Byung
Hyo Kim, Kwangsoo Shin, Soon Gu Kwon, Youngjin Jang, Hyun-Seok Lee, Hyunjae Lee, Samuel Woojoo Jun, Jisoo Lee, Sang Yun Han, Yong-Hyeon Yim, Dae-Hyeong Kim, Taeghwan HyeonWe present a rapid and reliable method for determining
the sizes
and size distributions of <5 nm-sized iron oxide nanocrystals (NCs)
using matrix-assisted laser desorption/ionization time of flight (MALDI-TOF)
mass spectrometry (MS). MS data were readily converted to size information
using a simple equation. The size distribution obtained from the mass
spectrum is well-matched with the data from transmission electron
microscopy, which requires long and tedious analysis work. The size
distribution obtained from the mass spectrum is highly resolved and
can detect size differences of only a few angstroms. We used this
MS-based technique to investigate the formation of iron oxide NCs,
which is not easy to monitor with other methods. From ex situ measurements,
we observed the transition from molecular precursors to clusters and
then finally to NCs.