Photon correlation spectroscopy colloid size measurements

Filella, M., Zhang, J., Newman, M.E. and Buffie, J. (1997) Analytical applications of photon correlation spectroscopy for size distribution measurements of natural colloidal suspensions capabilities and limitations. Colloids Surf. A Physicochem. Eng. Aspects, 120, 27 16. 

Ledin, A. et al., Measurement in situ of concentration and size distribution of colloidal matter in deep groundwater by photon correlation spectroscopy, Water Res., 28, 1539, 1994. 

In this model, the buoyant mass is then the sum of the buoyant mass of the three components, assuming that these are independent of the mass of solvent occupied in the solvation shell. Thus, the mass of the adsorbed shell can be calculated if information about the mass and density of the core particle and the density of the macromolecule and solvent are known. Photon correlation spectroscopy, electron microscopy, flow FFF, or other sizing techniques can readily provide some independent information on the physical or hydrodynamic particle size, and pycnometry can be used to measure the densities of the colloidal suspension, polymer solution, and pure liquid. 

Colloid growth under different conditions was monitored using photon correlation spectroscopy, which measures the size of submicron particles. The size of colloid particles during the growdi process was measured with 90 Plus Particle Sizer (Brookhaven Instrument Co., Holtsville, NY). The reactions were conducted inside the cuvettes supplied with the instrument The experiments were run imder conditions listed in Table n. Measurements were made automatically by the instruments at pre-set times. KCl was added to the reaction solution to provide the same ionic strength for all runs. 

FIGURE 1.139 Particle size distributions in MCA (at tMCA=( ) 10 min and (b) 5 h) aqueous suspension of initial nanosilica A-300 at concentration of 5 wt% with respect to the particle number measured by the photon correlation spectroscopy method. (Adv. Colloid Interface ScL, 91, Gun ko, V.M., Zarko, V.I., Lehoda, R., and Chibowski, E., Aqueous suspensions of fumed oxides particle size distribution and zeta potential, 1—112, 2001e. Copyright 2001, with permission from Elsevier.)... 

Photon correlation spectroscopy — also dynamic light scattering (DLS) or quasi-elastic light scattering (QELS) — is a robust and rapid method for size determinations in the colloidal range (from about 5nm to 1 m ). In PCS, intensity fluctuations of the scattered light due to particle motion are measured in dependence on time. By the diffusion coefficient of the particles in the measurement fluid, the particle diameter can be calculated according the Stokes-Einstein Eq. (9.1) under the assumption of a spherical particle shape ... 

Particle sizing in colloidal dispersions is performed nowadays on a routine basis with Photon Correlation Spectroscopy (PCS) i. The increasing success of PCS is mainly based on the fact that it provides absolute estimates of particle sizes in a very short measuring time without severe sample preparation procedures and that easy to use commercial equipment is available. It is well known that PCS yields reliable results for monodisperse samples with particle sizes in the submicron range In the last decade many efforts have been spent for determinations of particle size distributions by PCS. It appeared that the interpretation of PCS measurements is considerably more difficult for polydisperse samples due to the ill-conditioned nature of the data inversion. The ill-conditioning is reflected in the fact that the resulting size distributions depend very sensitively on the data and on the inversion method These ambiguities in the answers for the particle size... 

The flowability of SD and SFD powders containing nanoparticles was assessed by measuring the bulk and tap density of the powder. Dissolving the powder in deionized water to form a colloidal dispersion and comparing the nanoparticle size before and after SFD and SD processing measured the reconstitution-rate of spray-dried and spray-freeze-dried nanoparticle formulations as described in Ali and Lamprecht [16]. The nanoparticle size was determined by photon correlation spectroscopy (Brookhaven Instruments Corporation, Holtsville, NY, USA) [16]. 

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