Temperature-programmed electrospray-differential mobility analysis for characterization of ligated nanoparticles in
De-Hao Tsai1, Frank W DelRio, John M Pettibone
1Materials Measurement Science Division, National Institute of Standards and Technology , Gaithersburg, Maryland 20899, United States.
Langmuir : the ACS Journal of Surfaces and Colloids
|August 14, 2013
Summary
Thermal treatment effectively reduces interference from salt nanoparticles (S-NPs) in electrospray-differential mobility analysis (ES-DMA), enabling accurate particle size distribution measurements for stabilized nanoparticles.
Area of Science:
- Nanomaterial characterization
- Analytical chemistry
- Surface science
Background:
- Characterizing nanoscale particles (NPs) in complex media is challenging due to interferences.
- Electrospray-differential mobility analysis (ES-DMA) is a powerful technique for particle size distribution (PSD) analysis.
- Adsorbed ligands and residual salts can complicate ES-DMA measurements.
Purpose of the Study:
- To develop and validate a temperature-programmed ES-DMA method for accurate PSD determination of NPs with adsorbed ligands.
- To investigate the effect of thermal treatment on salt nanoparticle (S-NP) interference.
- To assess the stability of TiO2-NPs and ligand effects on S-NP behavior.
Main Methods:
- Utilized an electrospray-differential mobility analyzer (ES-DMA) with a temperature-programmed aerosol flow.
- Employed transmission electron microscopy (TEM) for visual characterization and inductively coupled plasma mass spectrometry for elemental analysis.
- Investigated titanium dioxide NPs (TiO2-NPs) stabilized with citric acid (CA) and bovine serum albumin (BSA).
Main Results:
- Thermal treatment effectively reduced interference from electrospray-dried salt residual nanoparticles (S-NPs).
- Accurate PSD measurements were achieved above 200 °C for CA-stabilized TiO2-NPs and above 400 °C for BSA-stabilized TiO2-NPs.
- TEM confirmed S-NP shrinkage and TiO2-NP structural stability below 700 °C, with shape factor changes above 500 °C.
Conclusions:
- Temperature-programmed ES-DMA coupled with thermal treatment is effective for characterizing NPs in complex matrices.
- Ligand size influences the activation energy for S-NP volumetric shrinkage.
- The method enhances the reliability of NP characterization in the presence of adsorbed ligands and agglomerates.
