Asymmetrical flow field-flow fractionation with multi-angle light scattering detection for the analysis of structured nanoparticles

Andrea Zattoni, Diana Cristina Rambaldi, Pierluigi Reschiglian, Manuela Melucci, Silke Krol, Ana Maria Coto Garcia, Alfredo Sanz-Medel, Dierk Roessner, Christoph Johann

Research output: Contribution to journalArticlepeer-review


Synthesis and applications of new functional nanoparticles are topics of increasing interest in many fields of nanotechnology. Chemical modifications of inorganic nanoparticles are often necessary to improve their features as spectroscopic tracers or chemical sensors, and to increase water solubility and biocompatibility for applications in nano-biotechnology. Analysis and characterization of structured nanoparticles are then key steps for their synthesis optimization and final quality control. Many properties of structured nanoparticles are size-dependent. Particle size distribution analysis then provides fundamental analytical information. Asymmetrical flow field-flow fractionation (AF4) with multi-angle light scattering (MALS) detection is able to size-separate and to characterize nanosized analytes in dispersion. In this work we focus on the central role of AF4-MALS to analyze and characterize different types of structured nanoparticles that are finding increasing applications in nano-biotechnology and nanomedicine: polymer-coated gold nanoparticles, fluorescent silica nanoparticles, and quantum dots. AF4 not only size-fractionated these nanoparticles and measured their hydrodynamic radius (rh) distribution but it also separated them from the unbound, relatively low-Mr components of the nanoparticle structures which were still present in the sample solution. On-line MALS detection on real-time gave the gyration radius (rg) distribution of the fractionated nanoparticles. Additional information on nanoparticle morphology was then obtained from the rh/rg index. Stability of the nanoparticle dispersions was finally investigated. Aggregation of the fluorescent silica nanoparticles was found to depend on the concentration at which they were dispersed. Partial release of the polymeric coating from water-soluble QDs was found when shear stress was induced by increasing flowrates during fractionation.

Original languageEnglish
Pages (from-to)9106-9112
Number of pages7
JournalJournal of Chromatography A
Issue number52
Publication statusPublished - Dec 25 2009


  • Asymmetrical flow field-flow fractionation
  • Gold nanoparticles
  • Multi-angle light scattering
  • Particle size distribution analysis
  • Quantum dots
  • Silica nanoparticles

ASJC Scopus subject areas

  • Analytical Chemistry
  • Organic Chemistry
  • Biochemistry


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