Direct chiral resolution of metalaxyl and metabolite metalaxyl acid in aged mobile phases: the role of trace water.
Direct chiral resolution of metalaxyl and metabolite metalaxyl acid in aged mobile phases: the role of trace water.
复制标题
DOI：
10.1021/jf9044342
复制
发表时间：
2010-03
影响因子：
6.1
通讯作者：
Xiaoxiang Zhang;Tingting Xia;Jingwen Chen;Liping Huang;Xiyun Cai
中科院分区：
文献类型：
--
作者：
Xiaoxiang Zhang;Tingting Xia;Jingwen Chen;Liping Huang;Xiyun Cai
手性转化产物的分离极大地补充了对手性污染物立体化学的理解。在这项研究中，直接对甲霜灵及其主要降解产物甲霜灵酸，经常在环境中共存，进行了正相高效液相色谱与Chiralcel OJ-H柱的对映体拆分。（R）-甲霜灵酸和（S）-甲霜灵几乎平行键合到手性固定相上，倾向于分离，开始重叠，共洗脱，并再次分离，移动的流动相由正己烷、2-丙醇、乙酸和微量水组成。它们的上述竞争妨碍了在新鲜的移动的相中可接受的直接分离。老化的移动的相与3-5天的储存期，但是，显着提高了它们的分离，其中微量水从水分空气扩散被发现发挥了重要作用。微量水对峰宽和保留时间的影响不同，然后诱导峰分离增强，通过向新鲜的移动的相中故意加水证实。此外，没有研究的因素，包括温度，伴随分析物，和微量水，可以引起的手性固定相的构型的变化。同时实现对映体分离的两种化合物在老化或新鲜的移动的流动相与外源或添加水，并给出了令人满意的峰分离，所有与环境样品中的Rs值大于1.20。
The separation of chiral transformation products greatly complements the understanding of the stereochemistry of chiral pollutants. In this study, direct enantiomeric resolution of metalaxyl and its main degradation product metalaxyl acid, often co-occurring in the environment, was carried out in normal-phase high-performance liquid chromatography with a Chiralcel OJ-H column. (R)-Metalaxyl acid and (S)-metalaxyl, which were almost parallel bonding to the chiral stationary phase, tended to separate, started to overlap, coeluted, and separated again with subtle changes of the mobile phase consisting of n-hexane, 2-propanol, acetic acid, and trace water. Their competition above hampered an acceptable direct separation in fresh mobile phases. Aged mobile phases with a storage period of 3-5 days, however, significantly improved their separation, in which trace water from moisture air diffusion was found to play a major role. Trace water differentially affected peak width and retention times and then induced enhanced peak separation, confirmed by deliberate addition of water to fresh mobile phases. Furthermore, none of the studied factors, involving temperature, concomitant analytes, and trace water, could cause changes of the configuration of the chiral stationary phase. Simultaneous enantiomeric separation of both compounds was achieved in aged or fresh mobile phases with adventitious or added water and gave satisfactory peak separation, all with Rs values of more than 1.20 in environmental samples.