次亜塩素酸ナトリウム処理したL－チロシンより生成するクロロホルムの中間生成物質に関する検討

摘要

水道の消毒には塩素や次亜塩素酸ナトリウムが用いられ ており，浄水処理過程でクロロホルムが生成することばよ く知られている．一方，魚介類加工品や野菜類の殺菌にも 次亜塩素酸ナトリウムが食品添加物として使用されてい る． 著者らは既報において，次亜塩素酸ナトリウムで処理し た野菜よりクロロホルムが生成することを報告した．%Possible intermediates in the formation of chloroform during by the sodium hypochlorite (NaCIO) treatment of L-tyrosine were investigated using HPLC and LC/MS. One product showed the same MS characteristics as the substance formed by the NaCIO treatment of 4-hydroxybenzyl cyanide (4-HBC), and it was suggested to be m-chloro-4-hydroxybenzyl cyanide (m-C-4-HBC). Since m-C-4-HBC is not commercially available it was synthesized by treating 4-HBC with NaCIO, and purified by extraction with ethyl acetate, followed by HPLC on preparative isolation columns, using a column switching method. The product was confirmed to be 3 -chloro-4-hydroxybenzyl cyanide (3-C-4-HBC), by means of NMR spectral analysis. When L-tyrosine or 4-HBC was treated with NaCIO, 3-C-4-HBC and CHC1_3 were generated. When 3-C-4-HBC was treated NaClO, CHCl_3 was generated. Judging from these results, 3-C-4-HBC was confirmed to be an intermediate in the formation of CHC1_3 from L-tyrosine. Thus, the reaction pathway of CHC1_3 formation from L-tyrosine treated with NaCIO is concluded to be: L-tyrosine→4-HBC→3-C-4-HBC→CHCl_3.