Ionic surfactants anionic

Reversed or inverted micelles Double-chain surfactants with small head group areas Non-ionic surfactants Anionic surfactants in high salt concentrations, e.g. cardiolipin + Ca " ... 

Physical and ionic adsorption may be either monolayer or multilayer (12). Capillary stmctures in which the diameters of the capillaries are small, ie, one to two molecular diameters, exhibit a marked hysteresis effect on desorption. Sorbed surfactant solutes do not necessarily cover ah. of a sohd iaterface and their presence does not preclude adsorption of solvent molecules. The strength of surfactant sorption generally foUows the order cationic > anionic > nonionic. Surfaces to which this rule apphes include metals, glass, plastics, textiles (13), paper, and many minerals. The pH is an important modifying factor in the adsorption of all ionic surfactants but especially for amphoteric surfactants which are least soluble at their isoelectric point. The speed and degree of adsorption are increased by the presence of dissolved inorganic salts in surfactant solutions (14). 

The system of anionic surfactants is another example of organic compounds mixtures. The procedure of their determination is proposed using coordinate pH in two-dimensional spectra of ionic associates anionic surfactants with rhodamine 6G. This procedure was tested on the analysis of surfactant waters and domestic detergents. 

MacMillan and Wright [133] identified and measured saturated and unsaturated 1,3- and saturated 1,4-sultones in anionic surfactants by a series of separation maneuvers. Ion exchange treatment separates sultones from the bulk of the ionic surfactant. TLC concentrates the sultones systems for HPLC analysis. They found that pentane-ether is preferable to the usual hexane-ether system and that the addition of a little methanol sharpens the separations. Finally, HPLC using a micro-Porasil column with 90 1 isooctane/ethanol provides quali-... 

As alternatives to amphiphilic betaines, a wide range of cationic, anionic, and non-ionic surfactants including environmentally benign sugar soaps have been successfully used as colloidal stabilizers [201]. Electrochemical reduction of the metal salts provides a very clean access to water soluble nanometal colloids [192]. 

Surfactants employed for w/o-ME formation, listed in Table 1, are more lipophilic than those employed in aqueous systems, e.g., for micelles or oil-in-water emulsions, having a hydrophilic-lipophilic balance (HLB) value of around 8-11 [4-40]. The most commonly employed surfactant for w/o-ME formation is Aerosol-OT, or AOT [sodium bis(2-ethylhexyl) sulfosuccinate], containing an anionic sulfonate headgroup and two hydrocarbon tails. Common cationic surfactants, such as cetyl trimethyl ammonium bromide (CTAB) and trioctylmethyl ammonium bromide (TOMAC), have also fulfilled this purpose however, cosurfactants (e.g., fatty alcohols, such as 1-butanol or 1-octanol) must be added for a monophasic w/o-ME (Winsor IV) system to occur. Nonionic and mixed ionic-nonionic surfactant systems have received a great deal of attention recently because they are more biocompatible and they promote less inactivation of biomolecules compared to ionic surfactants. Surfactants with two or more hydrophobic tail groups of different lengths frequently form w/o-MEs more readily than one-tailed surfactants without the requirement of cosurfactant, perhaps because of their wedge-shaped molecular structure [17,41]. 

For analysis of surfactants, i.e. detection, identification and quantification, LC-TSP-MS and MS/MS are also qualified methods for substance-specific information [600-602]. A mixture of non-ionic surfactants, comprising nonylphenol ethoxylates [C9Hi9-(CeH4)-0-(CH2-CH2-0)m-H], anionic surfactants and PEG, was... 

Sonochemical reduction processes of Pt(IV) ions in the presence of anionic, cationic or non-ionic surfactants was investigated by Mizukoshi et al. [38]. During the processes, the color of the aqueous solution containing H2PtCl6 and surfactants... 

Some of the reports are as follows. Mizukoshi et al. [31] reported ultrasound assisted reduction processes of Pt(IV) ions in the presence of anionic, cationic and non-ionic surfactant. They found that radicals formed from the reaction of the surfactants with primary radicals sonolysis of water and direct thermal decomposition of surfactants during collapsing of cavities contribute to reduction of metal ions. Fujimoto et al. [32] reported metal and alloy nanoparticles of Au, Pd and ft, and Mn02 prepared by reduction method in presence of surfactant and sonication environment. They found that surfactant shows stabilization of metal particles and has impact on narrow particle size distribution during sonication process. Abbas et al. [33] carried out the effects of different operational parameters in sodium chloride sonocrystallisation, namely temperature, ultrasonic power and concentration sodium. They found that the sonocrystallization is effective method for preparation of small NaCl crystals for pharmaceutical aerosol preparation. The crystal growth then occurs in supersaturated solution. Mersmann et al. (2001) [21] and Guo et al. [34] reported that the relative supersaturation in reactive crystallization is decisive for the crystal size and depends on the following factors. 

Jandera, P., Urbanek, J. (1995). Comparison of chromatographic behavior of oligoethylene glycol nonylphenyl ether non-ionic and anionic surfactants in reversed-phase high-performance liquid chromatography. J. Chromatogr. A 689(2), 255-267. 

Many other products can be used as softeners but are less important commercially because of greater cost and/or inferior properties. Examples are anionic surfactants such as long-chain (C16-C22) alkyl sulphates, sulphonates, sulphosuccinates and soaps. These have rather low substantivity and are easily washed out. Nonionic types of limited substantivity and durability, usually applied by padding, include polyethoxylated derivatives of long-chain alcohols, acids, glycerides, oils and waxes. They are useful where ionic surfactants would pose compatibility problems and they exhibit useful antistatic properties, but they are more frequently used as lubricants in combination with other softeners, particularly the cationics. 

Courtot-Coupez and Le Bihan [209,210] determined the optimum pH (7.4) for extraction of non-ionic surfactants with the above complex-benzene system. Cobalt in the extract is estimated by AAS after evaporation to dryness and dissolution of the residue in methyl isobutyl ketone. The method is applicable to surfactant concentrations in the range 0.02-0.5 mg/1 and is not seriously affected by the presence of anionic surfactants. 

Crisp et al. [212] has described a method for the determination of non-ionic detergent concentrations between 0.05 and 2 mg/1 in fresh, estuarine, and seawater based on solvent extraction of the detergent-potassium tetrathiocyana-tozincate (II) complex followed by determination of extracted zinc by atomic AAS. A method is described for the determination of non-ionic surfactants in the concentration range 0.05-2 mg/1. Surfactant molecules are extracted into 1,2-dichlorobenzene as a neutral adduct with potassium tetrathiocyanatozin-cate (II), and the determination is completed by AAS. With a 150 ml water sample the limit of detection is 0.03 mg/1 (as Triton X-100). The method is relatively free from interference by anionic surfactants the presence of up to 5 mg/1 of anionic surfactant introduces an error of no more than 0.07 mg/1 (as Triton X-100) in the apparent non-ionic surfactant concentration. The performance of this method in the presence of anionic surfactants is of special importance, since most natural samples which contain non-ionic surfactants also contain anionic surfactants. Soaps, such as sodium stearate, do not interfere with the recovery of Triton X-100 (1 mg/1) when present at the same concentration (i.e., mg/1). Cationic surfactants, however, form extractable nonassociation compounds with the tetrathiocyanatozincate ion and interfere with the method. 

The surface active agents (surfactants) may be cationic, anionic or non-ionic. Surfactants commonly used are cetyltrimethyl ammonium bromide (CTABr), sodium lauryl sulphate (NaLS) and triton-X, etc. The surfactants help to lower the surface tension at the monomer-water interface and also facilitate emulsification of the monomer in water. Because of their low solubility surfactants get fully dissolved or molecularly dispersed only at low concentrations and at higher concentrations micelles are formed. The highest concentration where in all the molecules are in dispersed state is known as critical micelle concentration (CMC). The CMC values of some surfactants are listed in table below. 

In sludge anionic and non-ionic surfactants carboxylic acids hhydroxybutyrate hydroxy valerate chloroaliphatic compounds chlorophenols polychlorobiphenyls 4-nitrophenol mixtures of organic compounds chlorinated insecticides, phenoxy acetic acid type herbicides and organotin compounds. 

The non-ionic surfactants do not produce ions in aqueous solution. The solubility of non-ionic surfactants in water is due to the presence of functional groups in the molecules that have a strong affinity for water. Similarly to the anionic surfactants, and any other group of surfactants, they also show the same general property of these products, which is the reduction of the surface tension of water. 

The predominance of anionic and non-ionic surfactants is reflected by their sales figures for the Western Europe market, shown in Table 1.5. The major representatives of each surfactant group are discussed in terms of application, manufacturing and composition in the following sections. 

The determination of bismuth activity as an indicator of non-ionic surfactants also suffers from interference in environmental samples. Substance group specific methods also failed to detect different types of fluorine-containing anionic, cationic and non-ionic surfactants. Already marginal modifications in the precursor surfactant due to primary degradation or advanced metabolisation implicated their lack of detection [45]. 

Equidistant or clustered signals, characteristic of some anionic, nonionic or cationic surfactants (cf. Fig. 2.5.1(a) and (b). So the presence of non-ionic surfactants of alkylpolyglycolether (alcohol ethoxylate) type (AE) (structural formula C H2 i i-0-(CH2-CH2-0)x-H) could be confirmed in the formulation (Fig. 2.5.1(a)) applying APCI-FIA-MS in positive mode. AE compounds with high probability could also be assumed in the heavily loaded environmental sample because of the patterns of A m/z 44 equally spaced ammonium adduct ions ([M + NH4]+) shown in its FIA-MS spectrum in Fig. 2.5.1(b). 

The selectivity of negative or positive ionisation for most of the anionic or non-ionic surfactants, respectively. So, positive ionisation of this environmental extract made compounds recognisable, which were assumed to be AE surfactants because of their equally spaced signals of ions (cf. Fig. 2.5.1(a)). Negative ionisation of the same extract, however, proved the presence of the anionic linear alkylben-... 

These observations obtained from the application of different API techniques are determinative for qualitative and quantitative FIA results in the analysis of non-ionic and ionic surfactants. Therefore, both ionic surfactant types, anionic and cationic surfactant blends, besides a non-ionic AE surfactant blend were examined, recording their FIA-MS and MS-MS spectra from the blends before the spectra were generated from the mixture of all blends. The results, which show considerable variation, will be presented and discussed as follows. 

As an example of an anionic surfactant mixture frequently contained in detergent formulations, an AES blend with the general formula C H2 i i—O—(CH2—CH2—O) —SO3 was examined in the negative FLAMS mode. Because of the considerable differences observed between both API ionisation mode overview spectra, the ESI—FIA—MS(—) and the APCI—FIA—MS(—) spectra are reproduced in Fig. 2.5.3(a) and (b), respectively. Ionisation of this blend in the positive APCI—FIA—MS mode, not presented here, leads to the destruction of the AES molecules by scission of the O—SO3 bond. Instead of the ions of the anionic surfactant mixture of AES, ions of AE can then be observed imaging the presence of non-ionic surfactants of AE type. 

L.S. Clesceri, A.E. Greenberg and A.D. Eaton (Eds), Standard Methods for the Examination of Water and Wastewater. 20th Edition, American Public Health Association, Washington, DC, 1998, pp. 5-47 (5540 C, Anionic Surfactants as MBAS) and pp. 5-49 (5540 D, Non-ionic Surfactants as CTAS). 

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