In order to inspect the process of L-threonine chloride to TCAce and its influencing factors

a novel method using methyl tertiary butyl ether (MTBE) as extractant and 1

2-dibromopropane as internal standard for the determination of the disinfection by-products trichloroacetone (TCAce) by gas chromatography mass spectrometry(GC-MS) was described．The formation process of TCAce and its influencing factors were discussed with L- threonine as the precursor during the chloramination process．It was indicated from the formation process that the TCAce amount produced increased with the increase of pH value from 5.5 to 8.5. Under the experimental conditions

it was also shown that when the chlorine dosage increased from 5.46 to 21.84 ml

the TCAce formation amount increased. It was also shown that when the L-threonine dosage increased from 59.6 to 476.4 mg·L-1

the TCAce formation amount decreased. Temperature affected the TCAce formation from L-threonine a lot

especially in the range of 10—30℃. The TCAce formation amount increased with the increase of temperature. The formation process of TCAce chlorided by L-threonine contained substitution

oxidation reaction

amino diazotation

reduction and a series of complicated reaction.