Particle size characterization by quadruple-detector hydrodynamic chromatography

Abstract

Particle size and shape and their distribution directly influence a variety of end-use material properties related to packing, mixing, and transport of powders, solutions, and suspensions. Many of the techniques currently employed for particle size characterization have found limited applicability for broadly polydisperse and/or nonspherical particles. Here, we introduce a quadruple-detector hydrodynamic chromatography (HDC) method utilizing static multiangle light scattering (MALS), quasi-elastic light scattering (QELS), differential viscometry (VISC), and differential refractometry (DRI), and apply the technique to characterizing a series of solid and hollow polystyrene latexes with diameters in the approximate range of 40-400 nm. Using HDC/MALS/QELS/VISC/DRI, we were able to determine a multiplicity of size parameters and their polydispersity and to monitor the size of the particles across the elution profile of each sample. Using self-similarity scaling relationships between the molar mass and the various particle radii, we were also able to ascertain the shape of the latexes and the shape constancy as a function of particle size. The particle shape for each latex was confirmed by the dimensionless ratio rho identical with R (G,z )/R (H,z ) which, in addition, provided information on the structure (compactness) of the latexes as a function of particle size. Solid and hollow polystyrene latex samples were also differentiable using these methods. Extension of this method to nonspherical, fractal objects should be possible.

Impact of dose and surface features on plasmatic and liver concentrations of biodegradable polymeric nanocapsules

“…The methodology applied in this study for NC and NE preparation, AFM analyses and previous studies indicate that the NC are spherical. For spherical particles R g /R h of 0.775 is characteristic of spheres with uniform density, such as polystyrene latexes (Brewer and Striegel, 2009), values close to 1.0 are obtained with vesicles or hollow spheres (Stauch et al, 2002;Vezočnik et al, 2015), values above 1 are obtained with elongated or porous structures and values as low as 0.3 are characteristic of microgels (Kunz et al, 1983). These values are in agreement with literature values for similar types of NC (Roy et al, 2015) and liposomes (Vezočnik et al, 2015).…”

Size fractionation and size characterization of nanoemulsions of lipid droplets and large unilamellar lipid vesicles by asymmetric-flow field-flow fractionation/multi-angle light scattering and dynamic light scattering

“…The shape factor defined as a ratio between the R rms and the R h ( = R rms /R h ) depends on the average segment density in the particle and thus gives valuable information on the internal structure [43,53]. The shape factors for the LD suspensions with SM/Chol/TOG molar ratio of 1/1/4.7 and 4/1/11.7 were determined to be 0.89 and 0.81, respectively (Table 3).…”

Ravuconazole self-emulsifying delivery system: in vitro activity against <em>Trypanosoma cruzi</em> amastigotes and in vivo toxicity

“…The shape factor, which is calculated as the ratio of the gyration radius (by MALLS) by the hydrodynamic radius (by DLS), Rg/Rh, gives an insight into the mass distribution within the volume of each structure and the shape of the structure formed. Spherical structures with a uniform distribution of mass have Rg/Rh close to 0.775, 42 whereas values closer to 1.0 are typically obtained with spherical structures that have a nonuniform distribution of mass. 43 Approximate values of 0.88 for blank SEDDS and 0.72 for RAV-SEDDS at retention time (t R ) 16.25 min were obtained.…”