Verification of the need for optical purity measurement of chiral pesticide standards as agricultural reference materials
Verification of the need for optical purity measurement of chiral pesticide standards as agricultural reference materials
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DOI：
10.1007/s00769-008-0400-z
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发表时间：
2008-05
影响因子：
0.9
通讯作者：
Koichi Saito;M. Yato;Takeshi Ito;Yusuke Iwasaki;R. Ito;Y. Matsuki;H. Nakazawa
中科院分区：
文献类型：
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作者：
Koichi Saito;M. Yato;Takeshi Ito;Yusuke Iwasaki;R. Ito;Y. Matsuki;H. Nakazawa
本研究对市售的8种农药，即精二甲硫草胺、精敌敌畏、精吡氟禾草灵、茚虫威、精甲霜灵、精甲霜灵、精喹禾灵和烯效唑，进行了对映体和外消旋体的光学纯度测定。采用高效液相色谱法，以二极管阵列（PDA）检测器和圆二色谱（CD）检测器串联，实现了农药对映体的分离。用于对映体分离的手性柱是正相Chiralpak AD-H柱。移动的相为正己烷，加入各种醇作为极性改性剂。考察了乙醇用量、移动的相中酸的存在与否、柱温等因素对分离效果的影响，以及PDA和CD检测器的最佳检测波长。计算对映体过量（ee）作为光学纯度的表示。结果表明，所调查的部分农药的ee值与生产厂家提供的数据基本一致（雅阁）。而茚虫威、烯效唑、精喹禾灵和精吡氟禾灵的ee在34.1- 94.5%之间。这些结果表明，有必要进行光学纯度测试，除了化学纯度测试，光学活性农药。
In this study, optical purity measurement was performed on eight kinds of commercially available pesticide, namely, Dimethenamid-P, Dichlorprop-P, Fluazifop-P butyl, Indoxacarb, Metalaxyl-M, Mecoprop-P, Quizalofop-P ethyl, and Uniconazole-P, in both enantiomer and racemate forms. Chiral separation of each pesticide was achieved by using HPLC with a photodiode-array (PDA) detector and a circular dichroism (CD) detector, which were connected in series. The chiral column used for the enantiomeric separation was a normal phase Chiralpak AD-H column. The mobile phase wasn-hexane, with various alcohols added as polar modifiers. The study included investigation of the effects on enantiomeric separation of the percentage of alcohol used, the presence or absence of acid in the mobile phase, and the column temperature, and the optimum detection wavelengths of both PDA and CD detectors. Enantiomeric excess (ee) was calculated as an expression of optical purity. As a result, theeeof some pesticides investigated was approximately (over 95%) in accord with the data provided by manufacturers. However, theeeof Indoxacarb, Uniconazole-P, Quizalofop-P ethyl, and Fluazifop-P butyl was in the range 34.1–94.5%. These results suggest that there is a need to conduct optical purity tests, in addition to a chemical purity test, for optically active pesticides.