Isolation compounds from drinking water

Macroreticular resins, particularly the Amberlite XAD series, have been used extensively to isolate and concentrate trace organic compounds from drinking water (1-8). We have previously reported the use of an XAD cartridge for this purpose and have evaluated the system for the analysis of organophosphorus pesticides (OPs) (4), polynuclear aromatic hydrocarbons (PAHs) (5), phosphate triesters (TAAPs) (6), or-... 

Comparison of High Molecular Weight Organic Compounds Isolated from Drinking Water in Five Cities... 

Prepai ative isolation of nonvolatile and semivolatile organic compounds fractions (hydrophobic weak acids, hydrophobic weak bases, hydrophobic neutrals, humic and fulvic acids) from natural and drinking waters in optimal conditions was systematically investigated by solid-phase extraction method with porous polymer sorbents followed by isolation from general concentrate of antropogenic and/or toxic semivolatile compounds produced in chlorination and ozonation processes. 

Chloramphenicol is a highly active antibiotic that was first isolated from cultures of Streptomyces venezuelae but is now produced synthetically. It is unique among natural compounds in that it contains a nitrobenzene moiety. Chloramphenicol has been used both in treatment and prophylactically in food-producing animals for over 40 years, administered orally with the feed or drinking water to poultry, veal calves, swine, sheep, and lambs, and intramuscularly or intravenously to sheep, goats, pigs, and calves at a dosage of 2-4 mg/kg bw. In several countries, chloramphenicol has been also used in fish for the treatment of furunculoses on salmonids (22). 

Results of lead studies indicate that dissolved lead at 25 ppb is not isolated by the XAD-4 quaternary resin. However, if lead is precipitated in the drinking water sample, the resin acts as a filter, and the precipitated lead compounds collected on the resin can be dissolved by the acid/methanol eluant. Experiments with the presence of humic substances and lead were conducted because humic substances can act as chelating agents for heavy metals. Approximately 85 of the lead was recovered, but lead was removed from water because of the initial precipitation of this element. This phenomenon may not occur in actual field sampling because all lead compounds should be in a dissolved form. 

The isolation method of solvent extraction has been suggested as a potentially feasible process to concentrate trace organic compounds from finished drinking water (4). One positive attribute of the solvent extraction method is that its performance for any given compound is theoretically predictable from a partition coefficient of a compound between the water sample and an organic solvent. The partition coefficient can be experimentally determined for any solute in any two-phase solvent system (7, 8). Variables of the extraction procedure such as solvent-to-water ratio and the choice of solvents can be adjusted to achieve optimum recovery. 

Applications of HPLC Of the bioanalytical separation technologies described in this book, arguably HPLC has the widest range of applications, being adopted for the purpose of clinical, environmental, forensic, industrial, pharmaceutical and research analyses. While there are literally thousands of different applications, a few indicators of how HPLC has been used are as follows (i) Clinical quantification of drugs in body fluids (ii) Environmental identification of chemicals in drinking water (iii) Forensic analysis of textile dyes (iv) Industrial stability of compounds in food products (v) Pharmaceutical quality control and shelf-life of a synthetic drug product (vi) Research separation and isolation of components from natural samples from animals and plants. 

Other off-flavor compounds of microbial origin have been isolated and identified from cultured fish and drinking water supplies. p-Cyclocitral has a tobacco-like odor and has been isolated from blooms of the cyanobacterium Microcystis spp. [24] and the flesh of farm-raised channel catfish [25]. P-Cyclocitral does not appear to be a large off-flavor problem in aquaculture [18]. Isopropylmercaptan, a compound with an oniony odor, has been isolated from cultures of Microcystis sp. [26], and 1 -octen-3-one, a mushroom-like odor-producing compound, has been isolated from cultures of an Anabaena sp. [27]. In addition, offensive sulfur-containing compounds are released into the water during cyanobacterial cell decomposition [26,28],... 

The United States Public Health Services drinking water standards specify a 50 mg/1 maximum for lead, EPA [73] has shown that this limit is only infrequently exceeded in larger United States cities. The presence of lead in drinking water may result from the use of lead materials in the water distribution system. Naturally occurring lead in rocks and soils may be an important source of contamination in isolated instances but lead from industrial wastes represent a local and not a widespread problem. The disposition of lead compounds from gasoline is a major source of lead in water systems [73]. 

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