Turbidometric method

A dispersion of the sample is placed on top of a liq of greater density. The rate of sedimentation is detd by measuring the sediment vol at fixed time intervals. The results are converted to a size distribution by Stoke s Law Nitrogen Adsorption. The amt of N adsorbed on a sample is detd by carefully measuring the press change of a known vol of N exposed to a known wt of dry mat at constant temp. The info is used to detn the surface area which is converted to a particle size distribution Turbidometric Methods. The absorption of a beam of light passing thru a suspended sample in a suitable liq is measured as a function of time. 

The most commonly used methods for detn of the particle size distribution of fine AP are the Micromerograph and Turbidometric Methods. For coarser AP samples standard sieves are used (see below under Specifications)... 

Antibodies provide a very convenient and specific analytical tool for protein determinations, a role considerably enhanced by the availability of a wide range of monoclonal antibodies. Many antibodies are capable of precipitating the target protein and the resulting turbidity can be measured by either tur-bidometric or nephelometric methods. The various types of alternative immunoassay offer increased sensitivity over the turbidometric methods. 

Functionality Analysis. Solubility was determined on 1% (w/v) dispersion of protein in 0.2 M phosphate buffers at a pH of 3.0 to 8.0. After stirring for 0.5 hr, the dispersion was filtered (0.45 /xm. Millipore), and the filtrate was analyzed for protein by the BCA method (21). Emulsifying activity index (EAI), expressed as interfacial area/unit weight protein (mVg) / was assessed by the turbidometric method of Pearce and Kinsella (22). 

Drug solubility is one of the physicochemical parameters that receives lots of attention during preformulation testing. In the initial stages, solubility studies are usually kinetically determined, where the drug is placed in contact with the solvents and then the solubility is assessed using turbidometric methods almost instantaneously. 

Anhydride epoxy, pre-1970 Novolac epoxy, 1972 Flame-retarded novolac epoxy, 1975 Flame-retarded novolac epoxy, 1983 Flame-retarded novolac epoxy, 1985 From turbidometric method. ... 

Layne, E. (1957) Spectrophotometric and Turbidometric Methods for Measuring Protein, Methods Enzymol. 3, 447-454. 

EPA. 1984c. Evaluation of turbidometric methods for monitoring of asbestos fibers in water. Athens, GA U.S. Environmental Protection Agency, Office of Research and Development. EPA-600/4-84-071. NTIS PB84-2325I1. 

As might be expected, many membrane activities reflect the physical state of the membrane bilayer. An example of this is seen in Figure 4. Here the kinetics of protein mediated sugar transport through a lipid bilayer is seen to follow the melting of the bilayer. For these studies the human red blood cell hexose transport protein was removed from its native membrane and reconstituted into artificial membranes with a predetermined thermal profile. Sugar transport was monitored by a turbidometric method to obtain the parameters (maximum rate... 

A turbidometric method based on the extreme insolubility of the quinine salt of silicomolybdic acid was developed by Defasse (331). The reagent is a mixture of quinine sulfate, ammonium molybdate, HjSO, and HNO3, and owing to the large mass of precipitate formed by a small amount of silica, the turbidity permits rapid determination of silica down to 1 ppm in water as long as phosphorus is not present at concentration greater than I ppm. 

The hydrolysis of 0.06 M BAA by papain is a first-order reaction under the conditions of assay (100). Specific activity (Gi) is expressed as K (first-order rate constant calculated in decimal logarithms) per milligram of protein nitrogen per milliliter of reaction mixture. Protein nitrogen can be estimated by the turbidometric method of Btlcher (36). The nitrogen content of standard papain solutions is determined by micro-Kjeldahl analysis. 

Interactions between tumor cells and platelets can be analyzed by different methods. The ability of tumor cells to induce platelet aggregation ( tumor cells induced platelet aggregation TCIPA) is evaluated by the turbidometric assay (Menter et al., 1987 Watanabe et al., 1988 Sugimoto et al., 1991 Tang et al., 1993 Belloc et al., 1995). Besides, the ability of tumor cells to bind platelets can be evaluated by the classic adhesion assay (see below). 

Standard methods were used for chemical analyses of groundwater samples in the Geology Division Chemistry Laboratory of the Alberta Research Council. Concentrations of Ca, Mg, Na and K ions were determined by atomic absorption spectrometry. Turbidometric and volumetric titration methods were used to determine SO4" and Cl concentrations respectively. Concentrations of HCO3 and CO3 were determined by potentiometric... 

These measure growth turbidometrically, or less commonly may use a titrimetric method to measure the level of acid formed during growth. Turbidity may be measured either by means of a nephelometer, if growth has taken place in the appropriate tubes, or spectrophotometrically. The samples are compared with a control which has not been inoculated. The titrimetric method is based on the acid produced during metabolism. The response is complex as the formation of acid may be simultaneous with cell growth, lag behind cell growth, or be a mixture. The theory and mathematics are discussed by Hewitt and Vincent. ... 

Other detection methods, such as turbidometric titration (19) and Fourier transform infrared spectrometry (35), have been used for compositional detection in copolymer rubbers. 

The Diffractometer methods are used extensively to study the size of latex suspensions in the coating industry. For example, T. Kourti, A. F. MacGregor, A. E. Hamielec, Turbidometric Techniques -Capability to Provide the Full Size Distribution, Chapter 1 in the Symposium Series472, Particle Size DistrUmtion II, Assessment and Characterization, T. Provder (ed.), Published by the American Chemical Society, Washington, D. C., 1991. This book is the proceedings of a Symposium held in April, 1990. 

See for example, N. Whang, J. Wei, C. Hong and H. Zhang, The Influence of Refractive Index on Particle Size Analysis Using Turbidometric Spectrum Methods , Part. Part. Syst. Charact., 13 (1996) 238—244. 

In the method of determining chlorine in chlorobutyl and other chlorine-containing polymers [6] the sample is combusted in a 1-2 litre oxygen-filled combustion flask containing 0.01 M nitric acid. After the combustion the flask is allowed to cool and 0.01 M silver nitrate added. The combustion solution containing silver chloride is evaluated turbidometrically at 420 mm using a grating spectrophotometer. 

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