Organic solvents, nonionic surfactant

Features Compat. with inorganic detergent builders, organic chelates, nonionic surfactants, and polar solvents... 

Features Compat. with inorg. detergent builders, organic chelates, nonionic surfactants and polar solvents fomns ion pairs with anionic soaps and surfactants Properties APHA < 75 wh. waxy flake mild, soapy odor freely disp. in water, lower alcohols, ketones, and glycols m.p. 140 F flash pt. (Setaflash) 150 F pH (0.5% aq.) 5.0-7.0 85% act. 

Emulsifiers. Removing the remover is just as important as removing the finish. For water rinse removers, a detergent that is compatible with the remover formula must be selected. Many organic solvents used in removers are not water soluble, so emulsifiers are often added (see Emulsions). Anionic types such as alkyl aryl sulfonates or tolyl fatty acid salts are used. In other appHcations, nonionic surfactants are preferred and hydrophilic—lipophilic balance is an important consideration. 

Other examples of concentrated laundry liquids have been described in the literature [53]. These might be called nonaqueous or low-water formulations. They may contain nonionic and anionic surfactants, inorganic builders, enzyme and bleach additives, and an organic solvent such as a low mole AE [54]. Surfactant levels may range from 30% up to 80%. In some cases, the builder salts are dispersed as solid particles in the non-aqueous phase [55]. 

The solvent sublation procedure of Wickbold [18] is another method that has been used for the analysis of LAS present in seawater [19,20], The solvent sublation technique (gaseous stripping into organic solvent, often ethyl acetate) has also been used to isolate and concentrate nonionic surfactants, e.g. AEs and APEO in aqueous samples [21,22], The co-extracted interferences can be eliminated by cation/anion ion-exchange and alumina chromatography [23,24]. 

The assay solvent must be selected to maximize the differences between the amount of probe bound to the MIP and to the NIP (or the CP), considered to be entirely non-specific. When the assay is optimized in aqueous solutions, a small amount of nonionic surfactant such as Triton X-100 (0.5%, w/v) or miscible organic solvents, such as ethanol, may be added to increase polymer wettability. The additive may also help to reduce hydrophobic interactions, especially for MIPs based on ethylenglycoldimethacrylate (EGDMA) or divinylbenzene (DVB) [5], Competitive assays are usually carried out only with the MIP, although it is advisable to check that no competition is observed when the NIP/CP is used instead. 

Certain comb-type silicone surfactants have been shown to stabilize emulsions in the presence of salts, alcohol and organic solvents that normally cause failure of emulsions stabilized using conventional hydrocarbon surfactants and a study by Wang et al. [66,67] investigated the cause of this stability. Interaction forces due to silicone surfactants at an interface were measured using AFM. Steric repulsion provided by the SPE molecules persisted up to an 80% or higher ethanol level, much higher than for conventional hydrocarbon surfactants. Nonionic hydrocarbon surfactants lose their surface activity and ability to form micelles in... 

The advantages cited for the described nonionic micellar cloud point extraction schemes include the following (1) ability to concentrate a variety of analytes (with concentration factors of 10-75), (2) safety and cost benefits (i.e. the use of small amounts of nonionic surfactant as an extraction solvent obviates the need to handle the usually large volumes of organic solvent required in traditional liquid-liquid extractions so that the volatility, flammability, and cost are reduced), (3) easy disposal of the nonionic surfactant extraction solvent (i.e. the nonionic surfactant solution is reportedly easily burned in the presence of waste... 

The entire sample must be soluble to be separated. If it is not, sample preparation can be performed to remove insoluble endogenous sample components. If the solute is not soluble, the appropriate additives must be used to solubilize it. So long as wavelengths less than 220 nm are not required, 6 M urea is an excellent solvent. Both ionic and nonionic surfactants are also useful in this regard. Acetate buffers provide better solubility compared to phosphate buffers. These approaches maintain a totally aqueous system, which is most robust. Organic solvents are often used in CE, but migration time precision is usually worse compared to aqueous systems. 

Nanocapsule/nanosphere size ranges between 200 and 350 nm were observed to be affected by both the oil-ethanol ratio and the oil-monomer ratio [63, 64], It is also influenced by the particular oil, water-miscible organic solvent, and nonionic surfactant in the aqueous phase. The pH of the aqueous phase and the temperature also affect the size distribution. 

Talsma, H., Van Steenbergen, M. J., Borchert, J. C. H., Crommelin, D. J. A. (1994), A novel technique for the one-step preparation of liposomes and nonionic surfactant vesicles without the use of organic solvents. Liposome formation in a continuous gas stream The bubble method,/. Pharm. Sci., 83, 276-280. 

Common surfactants that have been used in MEKC, are listed in Table 3.1 with the respective critical micelle concentrations the most popular are SDS, bile salts, and hydrophobic chain quaternary ammonium salts. Selectivity can also be modulated by the addition to the aqueous buffer of organic solvents (methanol, isopropanol, acetonitrile, tetrahydrofuran, up to a concentration of 50%). These agents will reduce the hydrophobic interactions between analytes and micelles in a way similar to reversed-phase chromatography. Organic modifiers also reduce the cohesion of the hydrophobic core of the micelles, increasing the mass transfer kinetics and, consequently, efficiency. Nonionic... 

Micelles and cyclodextrins are the most common reagents used for this technique. Micellar electrokinetic capillary chromatography (MECC or MEKC) is generally used for the separation of small molecules [6], Sodium dodecyl sulfate at concentrations from 20 to 150 mM in conjunction with 20 mM borate buffer (pH 9.3) or phosphate buffer (pH 7.0) represent the most common operating conditions. The mechanism of separation is related to reversed-phase liquid chromatography, at least for neutral solutes. Organic solvents such as 5-20% methanol or acetonitrile are useful to modify selectivity when there is too much retention in the system. Alternative surfactants such as bile salts (sodium cholate), cationic surfactants (cetyltrimethy-lammonium bromide), nonionic surfactants (poly-oxyethylene-23-lauryl ether), and alkyl glucosides can be used as well. 

Eqs. 2-5 give accurate predictions of the retention with several types of surfactant (anionic, cationic, and nonionic) and organic solvent (alcohols and acetonitrile), and solutes of different polarity and charge, with errors usually below 3-5%. 

The resultant hydrolyzed, polar species can have a better interaction with the polar head group of the surfactant, resulting in the formation of ordered structures. Soler-illia et al. reported a modulation of hybrid interface approach, which relies on the addition of controlled quantities of water to the solution of the inorganic precursor and a nonionic surfactant in an organic solvent to obtain ordered mesostructures. 

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