302-17-0Relevant articles and documents
Kinetics and mechanistic investigation into the degradation of naproxen by a UV/chlorine process
Gao, Yu-Qiong,Gao, Nai-Yun,Chu, Wen-Hai,Yang, Qin-Lin,Yin, Da-Qiang
, p. 33627 - 33634 (2017)
In this study, UV irradiation combined with chlorine (UV/chlorine) was used to degrade naproxen (NPX), a typical non-steroidal anti-inflammatory drug (NSAID) widely used for the treatment of symptoms associated with inflammation, in water. Compared with UV irradiation alone and direct chlorination, the UV/chlorine process shows a synergistic effect on NPX degradation. The effects of different factors, including the chlorine dose, solution pH, and the presence of Cl-, HCO3- or humic acid (HA), on NPX degradation in the UV/chlorine process were investigated. The results indicated that the degradation of NPX followed pseudo-first-order kinetics in all cases, and the rate constant increased as the chlorine dose increased and decreased as the pH increased. The effects of the water matrix on UV/chlorine treatment were species-dependent. The NPX degradation rate was inhibited by the presence of HCO3- and HA but significantly improved by Cl-. LC/MS/MS analysis indicated that NPX decomposition in the UV/chlorine process was associated with decarboxylation, demethylation and hydroxylation. These results indicate that the UV/chlorine process is a promising technology for the treatment of water polluted by emerging contaminants, such as NPX. However, UV/chlorine can notably enhance the formation of disinfection by-products compared to direct chlorination, which should be carefully considered when integrating this process into drinking water treatment schemes.
Thermally induced oxidative decarboxylation of copper complexes of amino acids and formation of strecker aldehyde
Nashalian, Ossanna,Yaylayan, Varoujan A.
, p. 8518 - 8523 (2015/04/22)
In the Maillard reaction, independent degradations of amino acids play an important role in the generation of amino-acid-specific products, such as Strecker aldehydes or their Schiff bases. Such oxidative decarboxylation reactions are expected to be enhan
Metabolism of trichloroethylene and chloral hydrate by the Japanese medaka (Oryzias latipes) in vitro
Lipscomb, John C.,Confer, Patricia D.,Miller, Michael R.,Stamm, Steven C.,Snawder, John E.,Bandiera, Stelvio M.
, p. 325 - 332 (2007/10/03)
Trichloroethylene (TRI), a common groundwater contaminant, is readily metabolized by mammals to produce chloral hydrate (CH), trichloroacetic acid (TCA), and trichloroethanol (TCOH). Cytochrome P450 (CYP) and other enzymes are responsible for formation of these metabolites, which are implicated in TRI's toxicity and carcinogenicity. To establish the validity of the Japanese medaka (Oryzias latipes) as an alternate test species for TRI, we examined the metabolism of TRI and CH, as well as CYP expression, in medaka liver preparations. Trichloroethylene was incubated with medaka microsomal protein, and metabolites were extracted and analyzed using gas chromatography. Microsome-mediated metabolism of TRI was observed, and a K(m) value for TRI oxidation of 540 μM and a V(max) value of 213 pmol/min·mg-1 protein were obtained. Conversion of TRI to CH, TCA, and TCOH was found with medaka hepatic subcellular fractions. In addition, a sex difference in hepatic microsomal TRI metabolism, specific CYP content, and ethoxyresorufin O- deethylase activity was noted. The lower specific activity of preparations from the livers of female medaka is compensated for by increased total protein in the larger liver mass of the female. Immunochemical analysis showed that CYP1A was readily detectable in medaka liver, but CYP2E1 was present at very low levels. These data suggest that TRI metabolism in medaka liver preparations mimics that observed in mammalian systems and supports their use as an alternative test species in the evaluation of the toxicity of TRI.