Characterization And Identification Of Antiestrogenic By-products Of Phenylalaninec Chlorination

Wastewater reclamation and reuse is an effective approach to solve water shortage problem, and how to guarantee the quality of the reclaimed wastewater is a prominent issue. Disinfection plays a key role in preventing the spread of harmful pathogens when reusing wastewater,and chlorination is also widely used in wastewater reclamation and drinking water treatment. But harmful disinfection by-products (DBPs) may be formed during disinfection. Amino acids are considered as important precursors of DBPs. In this study, the antiestrogenic activity after chlorination of phenylalanine water solution was evaluated by yeast two-hybrid assay.For the first time, chlorination of phenylalanine (0.5mmol/L) was found to form antiestrogenic DBPs. The antiestrogenic activity of chlorinated phenylalanine increased with increase in chlorine doses from 0 to 0.5mmol/L, however decreased sharply after chlorine addition over 0.5mmol/L.By fractionating DBPs of chlorinated phenylalanine into different fractions, the by-product of 44mins retention time is identified as the benzaldehyde or phenylacetonitrile, and the rest by-products are unknown. Producing amount of the by-products of F1,F2,F4,F7,F8,F9,F10,F11 drop after rising with increase in chlorine doses from 0 to 2.0mmol/L. When the chlorine addition is 0.5mmol/L, The producing amounts of the by-products of F1,F2,F4,F7,F10,F11 are the biggest.Producing amount of the by-product of F3 drops after rising,but its producing amount does not basically change after chlorine addition over 1.0mmol/L.Producing amounts of the by-products of F5,F6 rise progressively.The experimental results also showed that the antiestrogenic activity of chlorinated phenylalanine increased with increase in chlorine doses from 0 to 0.5mmol/L. By fractionating DBPs of chlorinated phenylalanine into different fractions, the key fractions which are F5,F7,F10,F11 with high antiestrogenic activity were found.