Cloudy emulsions

The product upon dilution with water will form a cloudy emulsion which requires shaking before use. 

Addition of 5 mL of concentrated hydrochloric acid to the aqueous filtrate from precipitation of the -acid produces a cloudy emulsion, which. 

Radionuclides typically are measured in a liquid scintillation (LS) counter as an aqueous solution that is pipetted into a vial, mixed with a scintillation cocktail, and counted within a radiation shield by a dual photomultiplier tube (PMT) system. As described in Section 8.3.2, the cocktail consists of a scintillating substance in an organic solvent such as benzene. The mixture may be a cloudy emulsion, but this lack of visible-light transparency does not interfere with the effective transmission of the generated 3-eV photons to the PMT. 

Emulsions and Dispersions The mixture of hquids leaving a mixer is a cloudy dispersion which must be settled, coalesced, and separated into its liquid phases in order to be withdrawn as separate liquids from a stage. For a dispersion to Freak into separate phases, both sedimentation and coalescence of the drops of the dispersed... 

Chicken broth is cloudy because it is colloidal, containing microscopic particles of chicken fat suspended in the water-based soup. Like milk, cream or emulsion paint, the cloudy aspect of the soup is a manifestation of the Tyndall effect. Adding the eggshells to the colloidal solution removes these particles of fat, thereby removing the dispersed medium. And without the dispersed medium, the colloid is lost, and the soup no longer shows its cloudy appearance. We say we have broken the colloid. 

During the refining and processing of fuel, corrosion inhibitors, antifoulants, filmers, neutralizers, and other organic compounds may carry over into a finished product. These polar organics may attract and interact with water to tightly bind it into the fuel as an emulsion. The result is usually a cloudy, hazy fuel. These emulsions are often quite difficult to break. If the water present contains caustic, organic salts, or corrosion products, the emulsion may be quite stable. 

Emulsions are mixtures of liquids which are immiscible. Earlier in this chapter you found out that when two liquids are immiscible they do not mix but form two different layers. Oil and water are like this but if you shake the mixture it becomes cloudy. 

Liquid formulations can be used as pastes or slurries, dispersions, or emulsions (in aqueous or other solvents) to physically separate the compound to be protected. Dispersions, pastes, or slurries are not commonly used but are a feasible approach when highly concentrated products are needed. For instance, many early analytical enzymes were sold as crystal slurries to preserve stability. Dispersions can be prepared from dry materials. Most of the dispersions are visually cloudy in appearance due to the particle size of the dispersed compounds and are thus undesirable in most endproducts. 

In most cases, physical instabilities are consequences of previous chemical instabilities. Physical instabilities can arise principally from changes in uniformity of suspensions or emulsions, difficulties related to dissolution of ingredients, and volume changes [6], For instance, some cases where physical stability has been affected are cloudiness, flocculence, film formation, separation of phases, precipitation, crystal formation, droplets of fog forming on the inside of container, and swelling of the container [8],... 

In France, it is the custom before a meal to partake of an aperitif, usually an aniseed-flavoured spirit called pastis. Pastis (e.g. Ricard , Pernod ) when it comes out of the bottle is a clear, light brown coloured solution of volatile oils from the seeds of the anise plant (Pimpinella anisum), which impart the characteristic aniseed flavour to the drink, dissolved in approximately 40% v/v ethanol. When a pastis is drunk, it is mixed with water and ice, whereupon the liquid becomes cloudy. This happens because the anise oils are hydrophobic, non-polar liquids and not very water-soluble. They are only held in solution by the high alcohol content of the drink. When the alcohol is diluted with water, the oils come out of solution and form an emulsion of oil droplets in the aqueous phase. This is what gives the drink its cloudy appearance. Oral solutions of anise oils have been used pharmaceutically for their carminative action and as an aid to digestion for many years, although it seems to this author preferable to consume anise oils in the form of a pastis, rather than in the form of a bottle of medicine. 

The soft drink circle should be read from inner to outer circle. First of all, the world of soft drinks can be categorised into clear and cloudy products, as further described in 5.2.1.1 and 5.2.1.2. In these chapters, more information can be found on important raw materials, like juices, extracts and emulsions. Within these main categories of soft drinks, it is also important to differentiate between juice specialities, flavours, source of extracts and the principal bases of emulsions. 

Low juice content is defined by a content of 1 to 20% by weight of juice in the final drink. These products are mainly based on citrus juices. As mentioned before, citms juices provide good turbidity and stability even with low juice content. In combination with special raw materials made from citrus, like cloudy concentrates or peel oils, very stable low-juice drinks can be obtained. Turbidity comes from a complex mixture of dispersions of fruit cells and oil-in-water emulsions, stabilised by fruit pulp particles and hydrocolloid stabilisers, such as locust bean gum [9]. 

Many successful formulations are based on emulsion techniques. In these formulations, oil and water are mixed in such a way that small, uniformly shaped oil droplets are dispersed in the water phase (oil in water) or water droplets are dispersed in a continuous oil phase (water in oil). An emulsion appears as a cloudy suspension. When an oil-in-water emulsion has oil droplets so small as to produce a clear solution, then formulation is called a microemulsion. The oil phase of the emulsion can provide lipophilic proteins with some protection from enzymatic digestion while the product is in the intestinal tract. Water-in-oil microemulsion formulations have been developed for oral insulin delivery.50... 

The ability of an oil to remain liquid during refrigerator storage is determined by the cold test analysis crystallization resistance is measured as the time in hours before the oil appears cloudy at 32°F (CPC). Standardized AOCS Method Cc 11-53 requires that dry filtered oil be placed in a sealed 4-ounce bottle and submerged in an ice bath. A go-no-go examination for clarity after 5 hours is stipulated by the Official AOCS Method however, most laboratories practice the alternative procedure which continues the clarity examination until a cloud appears. The cold test procedure was developed to evaluate cottonseed oil for the production of mayonnaise and salad dressings. Oil that solidifies at refrigerator temperatures will cause an emulsion-break with a resultant separation of the oil and water phases. Currently, the cold test is also utilized to ensure that bottled oils for retail sale will not develop an unattractive appearance on the grocery shelf. 

Extra virgin olive oil is produced in a form of an emulsion or dispersion, which can persist for several months before full deposition of a residue. Today, there is a growing interest in cloudy (veiled) extra virgin olive oil, which some consumers consider as more green and not over-processed. However, this is not correct because the additional processing is only precipitation and filtering. 

As a preliminary to this experiment it is necessary to become familiar with a test for iodine. Grind in your mortar with 5 c.c. of water a lump of starch the size of a small pea, put the paste into a large test tube half full of water and boil until the liquid no longer looks cloudy. Dilute 5 c.c. of iodine solution with 10 c.c. of water and add a few drops of this diluted iodine to 5 c.c. of the starch emulsion. (1) What color appeared This is a test for iodine. (2) State the test for iodine. Add a few drops of sodium iodide solution to 5 c.c. of starch emulsion. (3) What occurred (4) Can starch be used as a test for combined iodine as well as for iodine alone ... 

The main difference between emulsions and microemulsions lies in the size and shape of the droplets of dispersed phase, which causes the differences in the thermodynamic stability of the two systems. Emulsions allow the drug to be administered as a dispersed oil solution and thus are kinetically stable but thermodynamically unstable. After storage or aging, droplets will coalesce and the two phases separate. Unlike emulsions, microemulsions are thermodynamically stable and phases do not separate on storage. Another important difference between the two systems is their appearance emulsions have a cloudy appearance, while microemulsions are transparent because of the lower dispersed phase size than macroemulsions. 

An emulsion is a mixture of two or more immiscible liquids, whose interface is stabilized by an emulsifier. Essentially, emulsion contains oil and water. Emulsions are inherently thermodynamically unstable system, often recognizable by their cloudy or white appearance since the substances do not mix homogenously. The mixed substances often separate due to reduction in the interfacial energy after a period of time. The possible mechanism of destabilization can be creaming, flocculation, or coalescence. The emulsions possess kinetic stability, which is lost after a period of time. The kinetic stability is associated with the presence of interfacial film around the dispersed droplets at the oil/water interface by the emulsifier. The interfacial film increases the interfacial viscosity, which retards the coalescence of the droplets. ... 

---