Light-scattering methods

The basic single-angle interval light-scattering method caimot accurately measure individual red blood cell or platelet volumes, but it can provide MCV and MPV. Red cells are bi-concave disks, and platelets ate rod to disk shaped Scattering intensities depend on the orientation in the flow cell. 

In principle, the two-angle interval method can produce all CBC parameters within a single measurement channel, uniquely providing ceU-by-ceU hemoglobin concentration. The mean of the concentrations provides an alternative (and direct) measurement of MCHC. The method also provides an alternative HGB measurement, because HGB may be set equal to (RBC x MCV x MCHC)/1000. This method, like the basic light-scattering method, uses the same flow cell to measure platelets and ted cells with the result that the method is capable of providing the CBC parameters RBC, HGB, HCT, MCV, MCHC, MCH, and PLT. The method can also count a sample s white blood cells if the sample s red blood cells have been lysed. 

Often in hyperbranched polymers obtained via SCVP, it is not possible to determine the DB directly via NMR analysis. Therefore, other methods, for example, viscosity measurements and light-scattering methods have to be used to confirm the compact structure of a hyperbranched polymer. Such characterizations of hyperbranched (meth)acrylates will be discussed in the next section. 

Absolute calibration is of critical importance for the determination of molecular weights by the light-scattering method. The scattered intensity is so low compared with the incident beam at a distance of a few cm. being of the order of 10 lo) that a reliable direct comparison of the two beams using the same photocell is impractical. Several methods have been used, with results which are not always comparable, however. 

In conclusion, the light-scattering method offers the advantage that... 

Xiang, T.-X. Anderson, B. D., Development of a combined NMR paramagnetic ion-induced line-broadening dynamic light scattering method for permeability measurements across lipid bilayer membranes, J. Pharm. Sci. 84, 1308-1315 (1995). 

Milon, A., T. Lazrak, A. M. Albrecht et al. 1986. Osmotic swelling of unilamellar vesicles by the stopped-flow light scattering method. Influence of vesicle size, solute, temperature, cholesterol and three a, Q)-dihydroxycarotenoids. Biochim. Biophys. Acta 859 1-9. 

Mn and Mw/Mn were determined by GPC using standard poly (MM A) whose Mw was measured by light scattering method. Solvent, toluene [M]0/solvent = 5 (vol/vol)... 

Polymerization was carried out with 10 mol% CSA in 1,2-dichloroethane at reflux. Determined by the light-scattering method. 

Determined by GPC Determined by light scattering method dppf=l,l -Diphenylphosphinoferrocene. 

Which will yield the higher apparent molecular weight values in the light-scattering method (a) a dust-free system or (b) one in which dust particles are present ... 

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