Organophosphate triesters

A rapid SPME method was developed for the determination of N-butyl-benzenesulfonamide (NBBS) plasticizer used, e.g., in polyamide and poly- 

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Organophosphate triesters (OPERs) are used as flame retardants and/or plasticizers in a wide range of polymers, in furniture upholstery, insulation, wall coverings, and floor finishing products. Triethyl phosphate (TEP), tri-n-butyl phosphate (TnBP), tri-iso-butyl phosphate (T/BP), tris(2-ethylhexyl) phosphate (TEHP), and tris(2-butoxyethyl) phosphate (TBEP) are commonly used as plasticizers in polymers,... 

Staaf T, Ostman C (2005) Organophosphate triesters in indoor environments. J Environ Monit 7 883-887... 

Tissue esterases have been divided into two classes the A-type esterases, which are insensitive, and the B-type esterases, which are sensitive to inhibition by organo-phosphorus esters. The A esterases include the arylesterases, whereas the B esterases include cholinesterases of plasma, acetylcholinesterases of erythrocytes and nervous tissue, carboxylesterases, lipases, and so on. The nonspecific arylesterases that hydrolyze short-chain aromatic esters are activated by Ca2+ ions and are responsible for the hydrolysis of certain organophosphate triesters such as paraoxon (Figure 10.10B). 

Synthesis of Phosphoric Acids and Their Derivatives. - The individual Rp-and Sp- isomers of the organophosphate triesters (1-6) were synthesized and isolated on a preparative scale through the kinetic resolution of racemic mixtures via the hydrolysis of a single enantiomer by the bacterial phosphotriesteraze (PTE).i... 

The hydrolysis of organophosphate triesters is a particular challenge that is of interest in the remediation of soils and waters contaminated by insecticides of this type, and in the destruction of related chemical warfare agents. The natural and most modified cyclo-... 

Future work in this area could include optimization and testing of (mutant and wt) GpdQ on a range of pesticides and nerve agents. Also co-immobilization should be considered to generate multifunctional bioremediation tools. For example OpdA or OPH could be envisioned as co-immobilization partners. They are specialized for organophosphate triesters while GpdQ is mainly a phosphodiesterase. 

The inactivation and detoxification of paraoxon and congeners are catalyzed by the so-called A-esterases, which, as discussed, comprise aryleste-rase (sometimes still called paraoxonase, EC 3.1.1.2) and phosphoric triester hydrolases (phosphotriesterases, EC 3.1.8) subdivided into aryldialkylphos-phatase (organophosphate hydrolase, paraoxonase, EC 3.1.8.1) and organophosphorus acid anhydrolases (EC 3.1.8.2 see Sect. 9.3.7) [65][69][106-108], These activities, which occur mostly in the mammalian liver and... 

The phosphoric acid triesters (organophosphates, not to be mistaken for organophosphorous pesticides) are, like phthalates, plasticizers mixed into polymers to increase flexibility and workability. Unlike phthalates they are remarkable flame retardants as well. The total European production of phosphorous-base flame... 

O-Dealkylation O-Dealkylation of alkyl groups of the ester or ether structures of insecticides occurs frequently, but it also involves an unstable a-hydroxy intermediate as found in N-dealkylation. For example, methoxychlor is O-demethylated by the system (Figure 8.6). O-Dealkylation is known to occur with a wide variety of organophosphates, including certain dimethyl triesters. O-Dealkylation results in detoxification. 

Methods have been published that allow the classification of two types of esterases, the carboxylic ester hydrolases (CEHs) and the phosphoric triester hydrolases (PTEHs) (Anspaugh and Roe, 2004). The CEHs contain the B-esterases, which are inhibited by organophosphates. B-esierases include many other esterases, such as CarbE, acetylcholinesterase (AChE), cholinesterases (ChE), aryleslerases, sterol esterases, insect juvenile hormone esterases, aixl others. The determination of A-esterases uses a protocol for the detection of PTEHs. The PTEH assay allows for the identification of two subclasses of esterases, the A-esterase (known as aiyldialkylphos-phatase) and ditsopropyl fluorophosphatase. Both these enzymes metabolize OP compounds. 

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