Perfluorinated surfactants

The toxicology of perfluorinated surfactants varies greatly most are harmless, whilst some are amongst the most toxic non-proteins known, the structural differences between the two often being relatively slight. Hence caution is needed in their use, even though they are so strongly surface-active that they can be used in much smaller quantities than other surfactants. 

ESI operating in the negative ion mode has been the interface most widely used for the analysis of anionic perfluorinated surfactants. In addition, ESI has also been optimized for the determination of neutral compounds such as the sulfonamides perfluorooctanesulfonamide (PFOSA), perfluorooctanesulfonami-doacetate (A-EtFOSAA), and t-Bu-PFOS. The use of APPI has been explored in few works [126-128], Takino et al. [126] found as the main advantage of this technology, the absence of matrix effects, but the LODs were considerably higher than those obtained by LC-ESI-MS-MS. 

It was only recently that the use of aqueous film-forming foams (AFFF) containing perfluorinated surfactants was recognised as a source of groundwater pollution (Table 6.7.3). 

Moody, C.A., Kwan, W.C., Martin, J.W., Muir, D.C.G. and Mabury, S.A. (2001) Determination of perfluorinated surfactants in surface water samples by two independent analytical techniques liquid chromatography/tandem mass spectrometry and 19F NMR. Anal. Chem., 73, 2200. 

Moody, C. A., Martin, J. W., Kwan, W. C., Muir, D. C. G. and Mabury, S. A. (2002) Monitoring perfluorinated surfactants in biota and surface water samples following an accidental release of fire-fighting foam into Etobicoke Creek. Environ. Sci. Technol., 36, 545. 

In the last of the six papers Hong and Huang have examined how added surfactants such as FC-143, ammonium perfluorooctanoate [CF3(CF2)6 CO2NH4], influenced the Ti02-photocatalyzed decomposition of a large number of PCB congeners adsorbed on soils [102]. The authors concluded that the perfluorinated surfactants are photostable and do not get directly involved in the photochemistry of the chlorobiphenyls (unlike the surfactants mentioned earlier), and the surfactants extract the PCBs from the soil which are then expeditiously photoxidized on TiC>2. This represents a novel two-stage procedure to remove PCBs from soil and then destroy them. 

Moody, C. A., Eield, J. A. Perfluorinated surfactants and the environmental implications of their use in fire-fighting foams. Environmental Science and Technology, 34(18) 3864—3870 (2000). 

An intermediate phase of tetragonal syiiunetry - the T phase - has also been detected in a number of systems. A rod structure related to a square mesh surface was foimd to agree well with X-ray and NMR data on a perfluorinated surfactant-water mixture forming the T phase [22], [34]. These examples demonstrate that surfactant or lipid monolayers lining mesh surfaces as well and bilayers wrapped onto three-periodic minimal surfaces (IPMS) are indeed found in these self-assembled systems. 

Similar to other fluoropolymers and fluoroelasto-mers, such as PTFE, FEP, PFA, etc., low-level perfluorinated surfactants or chemicals, such as ammonium perfluoro-octanoate (APFO), etc. may be used in some fluoropolymer production as an emulsifier. These perfluorinated compounds are mostly extremely stable, degrade slowly, and therefore persist in the environment. These surfactants have varying ecotoxicity profiles, and users should contact their supplier for a more detailed ecotox information for their particular product.Industrial efforts are being made to reduce or even eliminate the use of such perfluorinated surfactants in their products and/or manufacturing processes. 

Adsorbed gelatine molecules alone do not show a frequency dependence of surface elasticity (Fig. 6.19), which corresponds to a behaviour of an insoluble monolayers. The presence of surfactants changes the elastic and relaxation behaviour dramatically. With increasing SDS concentration the elasticity modulus (frequency independent plateau value of the elasticity) first increases and then decreases. The dynamic behaviour of the mixed adsorption layer changes from one completely formed by gelatine molecules to an adsorption layer completely controlled by surfactant molecules (Fig. 6.20). A similar behaviour can be observed for CTAB and a perfluorinated surfactant (Hempt et al. 1985). 

Popkova, V.Ya. German, L.S. Preparation of a new precursor of perfluorinated surfactants (perfluorohexyl)thiirane. J. Fluorine Chem. 1990, 49, 159. 

PREPARATIVE TECHNIQUES Emulsion polymerization (a) 300-800 psig, perfluorinated surfactant initiator, 65-85°C, 2-6 h (b) 2001bin, 50-110°C, fluorinated surfactant,... 

A short report from Kometani etal. [226] describes the same synthetic method, using the system water/sc CO2 and adding a perfluorinated surfactant (PFPE) and AgC104 in it to obtain the microemulsion. The conditions of supercritical CO2 were rather mild (see Section 1.3). 2-propanol was added for promoting photoreduction (UV light, X = 254 nm) of Ag. The size of the silver particles was 10-15 nm, though the microemulsion core radius was only 2 nm. 

Dimethylbenzylammonium chloride Fragrance materials Perfluorinated surfactants... 

Renner, R. Concerns over common perfluorinated surfactant. Environ. Sci. Technol. 2003, 37, 201A. 

Fluorinated surfactants have been commercially available since the 1950s. The first available were perfluoroalkyl sulfonates (e.g., perfluorooctane sulfonate, CgFisSOs, PFOS) and perfluoroalkyl carboxylic acids (e.g., perfluorooctanoic acid, C7F15COOH, PFOA) manufactured using the electrochemical fluorination (ECF) process [10]. The unique properties (e.g., surface tension lowering in aqueous systems, high chemical and thermal stability) of these acids and their derivatives when used at low concentrations resulted in their widespread use in industrial processes and consumer uses [11-13]. The most common commercially produced perfluorinated surfactants are the perfluoroalkyl acids (PFAAs) ... 

Murakami M, Kuroda K, Sato N et al (2009) Groundwater pollution by perfluorinated surfactants in Tokyo. Environ Sci Technol 43 3480-3486... 

Higgins CP, Luthy RG (2006) Sorption of perfluorinated surfactants on sediments. Environ Sci Technol 40 7251-7256... 

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