Two new protocols for surface characterization have been published on the NCL Assay Cascade Protocols webpage.
PCC-16 describes PEG quantitation for PEGylated colloidal gold nanoparticles using reversed phase high performance liquid chromatography (RP-HPLC) and charged aerosol detection (CAD). Two different techniques are described in the protocol, and provide a means to quantitate total, bound, and unbound PEG. More information on this protocol can be found in the recent publication: Smith, M.C., Crist, R.M., Clogston, J.D., and McNeil, S.E., Quantitative analysis of PEG-functionalized colloidal gold nanoparticles using charged aerosol detection. Anal Bioanal Chem. 2015, 407(13), 3705-3716. PMID: 25749798
PCC-17 describes surface coating quantitation on metallic nanoparticles using thermogravimetric analysis (TGA). The protocol can be adapted for a variety of functionalized metallic nanoparticles, as it has tremendous flexibility with regards to both the surface coating and nanoparticle material.
If you have any questions on either of these protocols, please let us know.