Laser light scattering methods

On the other hand, a liquid/liquid interface is fluctuating thermally in the time scale of tens of picoseconds, and this induces thermal capillary waves as discussed above. Thermal capillary waves at a flat liquid/liquid interface have been studied by laser light-scattering methods, and the wavelength of the capillary wave (2) has been reported to be A 102 /im [29-31], A large... 

A laser light scattering method was used to characterize the particle size distribution of agglomerates and primary particles of Drug A using 0 and 30 s sonication times, respectively. As shown in Fig. 6.4, agglomerates are detectable when tested... 

Gamblin TC, King ME, Dawson H, Vitek MP, Kuret J, Berry RW, et al. (2000) In vitro polymerization of tan protein monitored by laser light scattering method and application to the study of FTDP-17 mutants. Biochemistry 39 6136-6144 Goedert M (1993) Tau protein and the neurofibrillary pathology of Alzheimer s disease. Trends Neurosci 16 460-465... 

Mantovani F, Grassi M, Colombo I, Lapasin R. A combination of vapor sorption and dynamic laser light scattering methods for the determination of the Flory parameter chi and the crosslink density of a powdered polymeric gel. Fluid Phase Equilib 2000 167(1) 63— 81. 

More recently, the electrophoretic laser light-scattering method was used to... 

Siddiqu and Wu [31] used a dynamic laser light scattering method to characterise an unfractionated PI in chloroform at 25 °C. The relatively small angular and concentration dependencies and translational diffusion coefficients measured by this technique enabled the PI to be characterised from only one measurement at a finite concentration and small scattering angle. Thus, this method could be used to characterise the molecular weight distribution of PI from the measured line-width distribution. 

The diffusion coefficient is related to the rate at which molecules migrate down a concentration gradient (it is treated in detail in Section 8.5) and can be measured by observing the rate at which a concentration boundary moves or the rate at which a more concentrated solution diffuses into a less concentrated one. The diffusion coefficient can also be measured by using laser light-scattering methods (Section 11.3). It follows that we can find the molar mass by combining measurements of sedimentation and diffusion rates (to obtain S and D, respectively). 

Jon DI, Rosano HL, Cummins HZ (1986) Toluene/water/1-propanol interfacial tension measurements by means of pendant drop, spinning drop, and laser light-scattering methods. J Colloid Interface Sci 114 330-341... 

PERSPECTIVES OF APPLICATION MULTI-ANGLE LASER LIGHT SCATTERING METHOD FOR QUALITY CONTROL OF MEDICINES... 

Under the same reaction conditions for the same systems the effect of compatibilizers on the time of onset of phase separation was studied using a laser light scattering method. The time of the onset of phase separation was determined from the inflection of the curve of the time dependence of the tight scattering intensity at the reaction temperature. Consider some experimental results. 

Normally (T is used without considering the solvent quality. However, a master low curve can only be established using such a method. In Table 5 a comparison of the model prediction with the experimental findings, obtained by laser light scattering measurements, is given. 

Different methods are available for the determination of the particle-size distribution of powdered solids [30]. These are optical microscopy (usually combined with image analysis), sieve analysis, laser light scattering of suspended particles, and electrical zone sensing. 

The vesicle size is an important parameter not only for in-process control but particularly in quality assurance, because the physical stability of the vesicle dispersion depends on particle size and particle size distribution. An appropriate and particularly quick method is laser light scattering or diffraction. Laser light diffraction can be applied to particles > 1 pm and refers to the proportionality between the intensity of diffraction and the square of the particle diameter according to the diffraction theory of Fraunhofer. 

Unfortunately, these indices are difficult to determine. Furthermore, most vesicle dispersions contain a dispersed mesophase with particle sizes below 200 nm up to 1 pm. Therefore photon correlation spectroscopy (PCS), on the basis of laser light scattering, provides an appropriate method of investigation [18]. 

Frake et al. compared various chemometric approaches to the determination of the median particle size in lactose monohydrate with calibration models constrncted by MLR, PLS, PCR or ANNs. Overall, the ensuing models allowed mean particle sizes over the range 20-110/tm to be determined with an error less than 5 pm, which is comparable to that of the laser light diffraction method nsed as reference. Predictive ability was similar for models based on absorbance and second-derivative spectra this confirms that spectral treatments do not suppress the scattering component arising from differences in particle size. 

Selected entries from Methods in Enzymology [vol, page(s)] Anisotropy effects, 261, 427-430 determination by dynamic laser light scattering (quasi-elastic light scattering), 261, 432-433 determination for nucleic acids by NMR [accuracy, 261, 432-433 algorithms, 261, 11-13, 425, 430 carbon-13 relaxation, 261, 11-12, 422-426, 431, 434-435 cross-relaxation rates, 261,419-422, 435 error sources, 261, 430-432 phosphorus-31 relaxation, 261, 426-427, 431 proton relaxation, 261,51,418-422 relaxation matrix calculations, 261,12] deuterium solvent viscosity effects, 261,433 effect... 

Figure 8. Molecular weight distribution of branched PVAc (B...) as determined by laser light scattering (LLS) and size exclusion chromatography (SEC)/viscometry. A comparison of results by the two methods is listed in Table 2.

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