Turbidity techniques

Shiflett, Particle Size Investigation of Polyox WSR 301 Polymer Powders Using a Turbidity Technique", NSRDC 28-621 (1973) 45) Anon, Standard Method of Test for Fineness of Hydraulic Cement by the No 325 (45 p m) Sieve", ASTM C430-75 (1975) 46) D.J. 

Thrbidity is a spectroscopic technique determining the optical density of colloidal particles. A wavelength between 350 and 500 nm is the first choice for such studies [56], Thrbidity measurements can offer important information on the kinetics of membrane-surfactant interactions since membrane solubilization changes reflect changes to the optical density of the dispersion [57-60], It is also widely used as a technique to investigate liposome aggregation and fusion [61]. However the exact particle size of liposomes cannot be determined using turbidity techniques. 

Foam rheology has been a challenging area of research of interest for the yield behavior and stick-slip flow behavior (see the review by Kraynik [229]). Recent studies by Durian and co-workers combine simulations [230] and a dynamic light scattering technique suited to turbid systems [231], diffusing wave spectroscopy (DWS), to characterize coarsening and shear-induced rearrangements in foams. The dynamics follow stick-slip behavior similar to that found in earthquake faults and friction (see Section XU-2D). 

The most common colorimetric technique involves a reaction between ammonia and a reagent containing mercuric iodide in potassium iodide (Messier reagent) to form a reddish-brown complex. Turbidity, color, and hardness are possible interferences that can be removed by preliminary distiHation at pH 9.5. 

The caprolactam obtained must meet die specifications of permanganate number, volatile bases, hazen color, UV transmittance, solidification point, and turbidity in order to be used for repolymerization alone or in combination witii virgin CL.5 Reported CL purification methods include recrystallization, solvent extraction, and fractional distillation. One solvent extraction technique involves membrane solvent extraction. Ion exchange resins have been shown to be effective in the purification of aqueous caprolactam solutions. In one such process,... 

Flocculation values achieved from turbidity measurements using the light scattering technique showed improvement with nonylphenol ether carboxylic acid (4 mol EO) in particular. The oil solubilization rate has been found to be proportional to the surfactant micellar size [190]. 

It is generally assumed the fluorescence and Fourier transform mid-infrared (FT-IR) spectroscopies do not suffer from the above-mentioned inconveniences and may be applied to turbid samples. Front-face (fluorescence) and attenuated total reflection (FT-IR) techniques may provide information on the structure of adsorbed proteins. 

Light scattering technique was used in determining the oil solubilization rate. Debye s equation ( ) was used in the interpretation. The basic principle involves the measurement of the surfactant aggregate size during the solubilization. As the oil goes into the surfactant micelle, the increased size will be reflected by the turbidity of the solution. 

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