In the present study

the reaction of ciprofloxacin with free available chlorine was investigated. The reaction products were concentrated and isolated by solid phase column and analyzed by Mass Spectrometry and NMR. Five products were identified，in which monochloro and dichloroquinolones were the major compounds. Mass fragment pathways of identified products were also elucidated. Chlorination reaction center concentrated on the position C3 and C8 of the quinolone ring. Besides of chlorination

the piperazine ring on the position C7 of the quinolone ring was broken to form amine. The side chain alkylamine was further dealkylation and hydroxylation.