Effect of hypochlorite oxidation on cholinesterase-inhibition assay of acetonitrile extracts from fruits and vegetables for monitoring traces of organophosphate pesticides.

A reproducible method for monitoring traces of cholinesterase (ChE) inhibitors in acetonitrile extracts from fruits and vegetables is described. The method is based on hypochlorite oxidation and ChE inhibition assay. Four common representative samples of produce were selected from a supermarket to investigate the effect of different matrices on pesticides recoveries and assay precision.

Mutagenic potentials of Amberlite XAD-2-resin extracts obtained from river and drinking waters in the Northwest district of Chiba, Japan.

Amberlite XAD-2 resin extracts of river and drinking water sampled from the Northwest district of Chiba Prefecture in each month during the period from January to December 2008 were investigated to characterize and determine their mutagenic potentials and polycyclic aromatic hydrocarbon (PAH) levels. The extracts from the river water were shown to be mutagenic in Salmonella typhimurium TA98 (a flameshift mutagen) without S9 mix, with higher mutagenic responses in summer and early fall seasons. While the drinking water extracts exhibited weak mutagenicity in both the TA98 and TA100 strains (a base-pair substitution mutagen) without S9 mix, with high mutagenic responses in fall and early winter seasons.

Suppression of PCDD/Fs formation because of the presence of DEHP during the model slow combustion of 2,4,6-trichlorophenol.

The thermal reactions of 2,4,6-T(3)CP in the presence and absence of DEHP in a dry air stream was investigated using a silica flow reactor at a residence time of 10s and a temperature range from 450 degrees C to 850 degrees C. Two isomers of T(4)CDDs (1,3,6,8- and 1,3,7,9-T(4)CDDs) were the most abundant products during the combustion of 2,4,6-T(3)CP alone and were observed at temperatures ranging from 550 degrees C to 800 degrees C. In the presence of DEHP, we observed a remarkable decrease in the yields of T(4)CDDs during the combustion of 2,4,6-T(3)CP.

Formation of polybrominated and polychlorinated ethylphenoxyethylphenols (PXEPEPs) during aqueous chlorination of 4-ethylphenol solutions in the presence of bromide ions.

This investigation was undertaken to determine the effect of the bromide concentration on the formation of polyhalogenated ethylphenoxyethylphenols (PXEPEPs), including predioxins, during the chlorination of 4-ethylphenol in solution. An aqueous solution of 4-ethylphenol was treated with hypochlorite in the presence of various concentrations of bromide ions. The changes in the compositions of the halogenated products in hexane extracts of the chlorinated solution were analyzed by gas chromatograph (GC) and a flame ionization detector (FID) and mass spectrometry (MS).

Influence of experimental conditions on the formation of PCDD/Fs during the thermal reactions of 2,4,6-trichlorophenol.

In order to obtain information on thermochemical reactions of chlorophenols, which are well known as dioxin precursors, occurring during the combustion of municipal solid wastes, the combustion of 2,4,6-trichlorophenol (2,4,6-T(3)CP) in an air stream was investigated over a temperature range of 500-800 degrees C for a residence time of 1-20s using a quartz flow reactor. Gas chromatographic/mass spectrometric (GC/MS) analysis of the gaseous products and residues showed that 2,4,6-T(3)CP began to decompose at 500 degrees C and produced several compounds, with 1,3,6,8- and 1,3,7,9-tetrachlorodibenzo-p-dioxins (T(4)CDD) as the major products. In addition, more than fifty organic products were observed in our experimental conditions.