典型多环麝香在土壤-小麦系统的对映体选择性环境行为研究

佳乐麝香(HHCB)和吐纳麝香(AHTN)是多环麝香中使用最广泛的两种手性化合物,采用Agilent Cyclosil-B和HP-5MS毛细管柱串联,在气质联用仪上对两种多环麝香的对映体进行了同时拆分;采用盆栽实验,以HHCB和AHTN商业标准外消旋品中的对映体比率(ERs)作为参照,对小麦幼苗及根际土中HHCB和AHTN的ERs进行分析。结果表明:根际土中HHCB的ERtrans和ERcis值分别为1.13和1.09;小麦体内HHCB的ERtrans和ERcis值分别为1.32~1.50和1.17~1.57,且茎和叶中的对映体比率显著高于外消旋品。根际土中AHTN的ERs值为1.06;小麦体内AHTN的ERs值为1.46~1.68,与外消旋品有显著差异。上述研究结果说明HHCB和AHTN在根际土中发生对映体选择性降解的能力很低,但易于在小麦体内发生对映体选择性吸收,且(4S,7R)-HHCB、(4S,7S)-HHCB和3R-AHTN是小麦体内容易吸收累积的类型。

Enantioselective behavior of typical polycyclic musks in soil-wheat systems

Galaxolide(HHCB) and tonalide(AHTN) are common polycyclic chiral synthetic musks. The enantiomers/diastereomers of HHCB and AHTN were separated by gas chromatography-mass spectrometry(GC-MS) by connecting a HP-5MS column to the outlet of a Cyclosil-B column. Using an indoor pot-culture experiment, the enantiomeric compositions of racemic HHCB and racemic AHTN were determined as a reference. The enantiomeric compositions of HHCB and AHTN in the rhizosphere soil and wheat seedlings were also studied. The ER_trans and ER_cis values(ER=enantiomeric ratio) of HHCB in the rhizosphere soil were 1.13 and 1.09, respectively, and those in the wheat seedlings were 1.32~1.50 and 1.17~1.57, which were significantly higher than the ER of racemic HHCB. The ER of AHTN in the rhizosphere soil was 1.07, and the ER_s of AHTN in wheat seedlings were 1.46~1.58 which were significantly higher than the ER of racemic AHTN. The results showed that there was little enantioselective degradation of HHCB and AHTN in the rhizosphere soil, but there was considerable enantioselective accumulation in the wheat seedlings, and(4S,7R)-HHCB,(4S,7S)-HHCB, and 3R-AHTN were more prone to biological absorption in the wheat seedlings.