Determination turbidity

Direct methods of miscibility determination (turbidity measurements, microscopy, combinatorial approaches, etc.)... 

In turbid inshore waters these may become a very appreciable fraction of the total extinction, which rarely exceeds 0.3 in nitrite determinations. Turbidity blanks should be determined on the surface and 10-m samples of each cast. Measure at progressively greater depths until the value becomes appreciably constant. This value (generally less than 0.01 at below 25 m in offshore waters) is then roughly equal to the cell-to-cell blank (Sect G.l above) and may even be slightly negative. Turbidity blanks should be measured on separate 30-ml samples of the sea water to which 1 ml of sulphanilamide reagent has been added. 

For ethyl alcohol, two volumes of dicycZohexyl are mixed with one volume of the alcohol, a thermometer is introduced, and the mixture heated until it becomes clear. The solution is then slowly cooled, with constant stirring, and the temperature is determined at which the opalescent solution suddenly becomes turbid so that the immersed portion of the mercury thread of the thermometer is no longer clearly visible. This is the C.S.T. The water content may then be evaluated by reference to the following table. 

Quantitative Analysis of All llithium Initiator Solutions. Solutions of alkyUithium compounds frequentiy show turbidity associated with the formation of lithium alkoxides by oxidation reactions or lithium hydroxide by reaction with moisture. Although these species contribute to the total basicity of the solution as determined by simple acid titration, they do not react with allyhc and henzylic chlorides or ethylene dibromide rapidly in ether solvents. This difference is the basis for the double titration method of determining the amount of active carbon-bound lithium reagent in a given sample (55,56). Thus the amount of carbon-bound lithium is calculated from the difference between the total amount of base determined by acid titration and the amount of base remaining after the solution reacts with either benzyl chloride, allyl chloride, or ethylene dibromide. 

Ka.un. This fossil resin, classified as a copal, is found in the South Pacific, primarily in New Zealand. It formerly was used in protective coatings. It is still used in the Kauri-butanol test (ASTM D1133) to determine the volume of thinner that can be added to a varnish formulation without causing turbidity. 

Although color and turbidity of acid products are important properties, there is Httie standardization in such measurements. A ftequentiy used procedure is to determine color and turbidity by comparison with standards originally developed by the American PubHc Health Association (APHA) for examination of water (151). 

Sodium thiosulfate is determined by titration with standard iodine solution (37). Sulfate and sulfite are determined together by comparison of the turbidity produced when barium chloride is added after the iodine oxidation with the turbidity produced by a known quantity of sulfate iu the same volume of solution. The absence of sulfide is iadicated when the addition of alkaline lead acetate produces no color within one minute. 

Polymerization-grade chloroprene is typically at least 99.5% pure, excluding inert solvents that may be present. It must be substantially free of peroxides, polymer [9010-98-4], and inhibitors. A low, controlled concentration of inhibitor is sometimes specified. It must also be free of impurities that are acidic or that will generate additional acidity during emulsion polymerization. Typical impurities are 1-chlorobutadiene [627-22-5] and traces of chlorobutenes (from dehydrochlorination of dichlorobutanes produced from butenes in butadiene [106-99-0]), 3,4-dichlorobutene [760-23-6], and dimers of both chloroprene and butadiene. Gas chromatography is used for analysis of volatile impurities. Dissolved polymer can be detected by turbidity after precipitation with alcohol or determined gravimetrically. Inhibitors and dimers can interfere with quantitative determination of polymer either by precipitation or evaporation if significant amounts are present. 

The aqueous micellai solutions of some surfactants exhibit the cloud point, or turbidity, phenomenon when the solution is heated or cooled above or below a certain temperature. Then the phase sepai ation into two isotropic liquid phases occurs a concentrated phase containing most of the surfactant and an aqueous phase containing a surfactant concentration close to the critical micellar concentration. The anionic surfactant solutions show this phenomenon in acid media without any temperature modifications. The aim of the present work is to explore the analytical possibilities of acid-induced cloud point extraction in the extraction and preconcentration of polycyclic ai omatic hydrocai bons (PAHs) from water solutions. The combination of extraction, preconcentration and luminescence detection of PAHs in one step under their trace determination in objects mentioned allows to exclude the use of lai ge volumes of expensive, high-purity and toxic organic solvents and replace the known time and solvent consuming procedures by more simple and convenient methods. 

In general, the multiphasic heterogenous nature of the impact grade styrene-based polymers is the root cause of their opaque-turbid nature. In determining the transparency of the blends, size and the size-distribution pattern of the dispersed phase along with the refractive index difference between the continuous and the dispersed phases are two very important criterion [133]. 

The construction of calibration curves is recommended in nephelometric and turbidimetric determinations, since the relationship between the optical properties of the suspension and the concentration of the disperse phase is, at best, semi-empirical. If the cloudiness or turbidity is to be reproducible, the utmost care must be taken in its preparation. The precipitate must be very fine, so as not to settle rapidly. The intensity of the scattered light depends upon the number and the size of the particles in suspension, and provided that the average size of particles is fairly reproducible, analytical applications are possible. 

Discussion. Phosphate ion is determined nephelometrically following the formation of strychnine molybdophosphate. This turbidity is white in colour and consists of extremely fine particles (compare ammonium molybdophosphate, which is yellow and is composed of rather large grains). The precipitate must not be agitated, as it tends to agglomerate easily it is somewhat sensitive to temperature changes. 

Turbidimetric analysis determinations by, 729 general discussion on, 726 instruments for, 727 Turbidity method for D. of silver, 347 Tyndall effect 419, 726... 

Acetone and Aldehydes. Determine the acetone and ethanol content in accordance with ASTM D1612. The sample is reacted with Nessler s reag and the turbidity that is produced is compared to a standard contg the equivalent of 0.003 weight % acet... 

Turbidimetric titration has also been applied to one-phase titration of alcohol sulfates and other anionic surfactants. The titration is carried out with hyamine 1622 in aqueous solution without the organic phase and indicator and the endpoint is taken as the point of maximum turbidity. The presence of nonionics and inorganic salts at high concentration interfere with the endpoint determination [243]. 

Turbidity measurements were determined using the dipping probe colorimeter. The light frequency was 650 nm. Deionized water transmittance was set at 90. The surfactant test solutions were stirred ( — 3500 rpm) and maintained at 75°C. Active surfactant concentration was 0.1% wt. Solution volume was 100 cm1. A 26.5% CaCU (95,699 ppm CaJ+) solution was added via syringe in 0,10 ml increments to the lower portion of the surfactant solution. 

This section deals with the experimental determination of the rate of oil solubilization in aqueous solutions of AOS and IOS [70]. The experimental method [71] consists of injecting 25 pi of n-hexadecane (containing 5 wt % Dobanol 45-3 as an emulsifier) into 50 ml water this produces a turbid macroemulsion upon vigorous stirring. At the start of the experiment, a concentrated solution of the surfactant under test is injected and the decrease in turbidity is followed with a photometer. The time elapsed to reach 90% of the initial turbidity is recorded (t ) and the pseudo rate constant of oil solubilization is calculated from... 

When the CMC determination is made by surface tension measurements, the resulting curve appears without minimum as a single surfactant. It is probable that an inversion takes place through the adsorption of the LSDA onto the surface of the Ca soap micelle, so that complete precipitation does not occur [23]. Zhang and Xiao [32] are of the opinion that the dispersion comes from the union of LSDA with the free ionic soap molecules. The particles from the soap-LSDA mixture are far larger than the corresponding soap molecules in soft water and therefore result in turbidity in hard water. 

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