Quate

CONSTANTS FOP ZERO PRESSURE REFERENCE FUGACITY f QUAT ION... 

Binnig G, Quate C F and Gerber Ch 1986 Atomic force microscope Phys. Rev. Lett. 56 930... 

Quaternary Ammonium Compounds. These compounds (quats) have the following general formula ... 

The quats are an extremely important group in medical and sanitary appHcations, with comparatively lirnited industrial appHcations. Activity against bacteria of pubHc health importance is absolutely required, with a lesser demand being made for antibingal activity. 

The mechanism of action of quats has been widely studied. It is generally agreed that their iateraction with the bacterial cell membrane is the primary event resulting ia antimicrobial activity (16,17). 

Regulatory pressures which have limited the iatroduction of new chemistries have led to a substantial trend to obtain innovation through combiaation. One apparentiy successful iatroduction is the combination of a quat with a polyphase for sapstain prevention on freshly sawn lumber (18). 

Quats are usually moderately soluble ia water, but this varies widely owiag to the range of groups bonded to the nitrogen. They are fundamentally nonreactive but act as surface—active cations. Compatibility with anionic detergents and activity ia the presence of hard water have been claimed for some quats (19). 

FiaaHy, a-olefias find their way iato the surfactant and disiafectant market through conversion, first to alkyl dimethyl amine, then to benzyl chloride quats (BAUMAC) and amine oxides. The former are used broadly as disiafectants, often ia combination with cleaning products. The latter is a direct active ia consumer and iadustrial cleaning products. 

Companies producing fatty amine quaternaries include Akzo Chemicals Inc. (Arquad) (73) Henkel Corporation (formerly General Mills) (Aliquat) (74) Humko Chemical (Witco Corporation) (Kemamine Q) (31) Jetco Chemicals (The Procter Gamble Company) (fet Quat) (75) Jordan Chemical Company (PPG Industries) (fordaquat and specialty quaternaries) (78) Lonza (Barquat and specialty quaternaries) (79) Sherex (Adogen) (76) and Tomah Products (Exxon Chemical Company) (Tomah Q) (77). 

Other Sanitizers and Treatment Systems. Other sanitizers and swimming pool treatment systems used to a limited extent are bromine, quats, ozone, ionizers, electrolyzers, uv, UV/H2O2, and Ag/H202. 

Algicides other than chlorine (or bromine) are used to a small extent, principally in the hotter southern and western regions of the U.S. They serve as a backup to chlorine primarily as a preventive or corrective measure against unbalanced pool conditions. The most widely used algicides are the quaternary ammonium compounds (quats), of which the -a1ky1dimethy1henzy1 ammonium chloride type (with groups) are the most common (see... 

The unique property of quats is the abHity to produce bacteriostasis in very high dilution (Table 6). Because of this abHity, and the carryover of the disinfectant in early test procedures, it was originally thought that these compounds were highly bactericidal. However, for bactericidal action, 10 to 20 times the concentration is required. The quats have a narrower antibacterial spectmm than the phenols, and are much more active against gram-positive... 

Fig. 4. Quaternary ammonium compounds (quats) tested as antimiciobial agents. Centiimide is a mistuie of dodecyl, tetiodecyl-, and...

Further developments have brought forth polymeric quats having antimicrobial properties (158—160). Different kinds of polyquats have been described with molecular weight from 2,000 to 60,000 (153). Polymeric quats have two characteristics that make them uniquely different from the monomeric quats. One is the absence of foaming, even at high concentrations. The other is their remarkably low toxicity in skin and eye irritation tests and... 

Considerable work has been done to try to explain why quats are antimicrobial. The following sequence of steps is beheved to occur in the attack by the quat on the microbial cell (/) adsorption of the compound on the bacterial cell surface (2) diffusion through the cell wall (J) binding to the cytoplasmic membrane (4) dismption of the cytoplasmic membrane (5) release of cations and other cytoplasmic cell constituents (6) precipitation of cell contents and death of the cell. 

Atomic force microscopy (AFM), invented in 1985 by Binnig, Quate, and Gerber [5.4,... 

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