title: Amino acids as precursors of trihalomethane and haloacetic acid formation during chlorination.
abstract: Twenty amino acids were chlorinated and examined for the formation of trihalomethane (THM) and haloacetic acid (HAA). The amino acids exhibited a high Cl(2) demand (3.4-10 mg Cl(2) mg(-1) C) but low THM formation (<4.19 microg mg(-1) C) except for tryptophan and tyrosine (45.8 - 147 microg mg(-1) C). Large variation in HAA yield occurred among the amino acids (from not detectable to 106 microg mg(-1) C). One group of amino acids, possessing chain structures, exhibited a slow increase in HAA formation (<6.2 micromol mol(-1) amino acid or <11.3 microg mg(-1) C) as the chlorine demand increased (3.4-8.9 mol Cl(2) mol(-1) amino acids). The other group of amino acids, containing ring structures (including tryptophan, tyrosine, histidine, phenylalanine, and proline) and two amino acids with chain structures (aspartic acid and asparagine), showed a fast increase in HAA formation (16-96 micromol mol(-1) amino acid or 27-106 microg mg(-1) C) with the increase in chlorine demand (5.2-15.9 mol Cl(2) mol(-1) amino acid). The ratios of TCAA to DCAA (mol/mol), derived from the amino acids, ranged between 0.01 and 1.10.
authors: Croucher Institute for Environmental Sciences, and Department of Biology, Hong Kong Baptist University, Kowloon Tong, Hong Kong, People's Republic of China.
authors: H C
authors: HC
authors: Hong
authors: M H
authors: MH
authors: Wong
authors: Y
authors: Y
authors: Liang
mesh_terms: D000085:Acetates / Q000737:chemistry*; D000596:Amino Acids / Q000737:chemistry*; D002713:Chlorine / Q000737:chemistry*; D054879:Halogenation; D022882:Trihalomethanes / Q000032:analysis*; D014867:Water; D018508:Water Purification
chemical_list: D000085:Acetates; D000596:Amino Acids; D022882:Trihalomethanes; D014867:Water; D002713:Chlorine