Ma Yun, Xu Chao, Wen Yuezhong, Liu Weiping
Research Center of Green Chirality, College of Biological and Environmental Engineering, Zhejiang University of Technology, Hangzhou, People's Republic of China.
Chirality. 2009 Apr;21(4):480-3. doi: 10.1002/chir.20624.
Chiral pesticides currently constitute about 50% of all pesticides dosage used in China, and this ratio is increasing as more complex structures are introduced. Dichlorprop methyl (DCPPM) is a chiral herbicide consisting of a pair of enantiomers. In this study, the enantiomeric separation of DCPPM was investigated by gas chromatography (GC) and high-performance liquid chromatography (HPLC) using chiral stationary phases (CSPs), and its enantiomeric degradation was characterized using a DCPPM-degrading bacterial strain isolated from an activated sludge from a textile-printing wastewater treatment plant. Baseline separation by both GC and HPLC was achieved. Incubation with DCPPM-degrading bacteria in different pH solutions showed that the R enantiomer was preferentially degraded over the S enantiomer of DCPPM. The degradation rate constant decreased with increasing pH in the order of k(pH5) approximately k(pH7) >k(pH9). In comparison, the enantioselectivity as indicated by EF followed the order of pH 7 > pH 9-pH 5.
目前，手性农药约占中国农药使用总量的50%，且随着引入的结构越来越复杂，这一比例还在上升。二氯丙酸甲酯（DCPPM）是一种由一对对映体组成的手性除草剂。本研究采用手性固定相（CSPs），通过气相色谱（GC）和高效液相色谱（HPLC）研究了DCPPM的对映体分离，并利用从纺织印染废水处理厂活性污泥中分离出的一株DCPPM降解细菌菌株对其对映体降解进行了表征。GC和HPLC均实现了基线分离。在不同pH值溶液中与DCPPM降解细菌一起培养表明，DCPPM的R对映体比S对映体优先降解。降解速率常数随pH值升高而降低，顺序为k(pH5)≈k(pH7)>k(pH9)。相比之下，以EF表示的对映选择性顺序为pH 7>pH 9>pH 5。
