One- and Two-Dimensional Direct Chiral Liquid Chromatographic Determination of Mixtures of Diclofop-Acid and Diclofop-Methyl Herbicides

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• 作者：Vanesa Guill&#xe9 ; n-Casla ; Luis Vicente P&#xe9 ; rez-Arribas ; Mar&#xed ; a Eugenia Le&#xf3 ; n-Gonz&#xe1 ; lez ; Luis Mar&#xed ; a Polo-D&#xed ; ez
• 刊名：Journal of Agricultural and Food Chemistry
• 出版年：2008
• 出版时间：April 9, 2008
• 年：2008
• 卷：56
• 期：7
• 页码：2303 - 2309
• 全文大小：435K
• 年卷期：v.56,no.7(April 9, 2008)
• ISSN：1520-5118

文摘

Simple one- and two-dimensional high-performance liquid chromatography (HPLC) methods for the simultaneous enantiomeric determination of alkyloxyphenoxypropionic acid herbicides is presented. Compounds studied were (R,S)-2-[4-(2,4-dichlorophenoxy)phenoxy]propionic acid (diclofop-acid) and (R,S)-2-[4-(2,4-dichlorophenoxy)]methyl propionate (diclofop-methyl). Mobile phases necessary to separate their enantiomers on an α₁-acid glycoprotein chiral stationary phase are different; therefore, the simultaneous separation by an isocratic mode is not possible. The chiral separation method proposed involves a one-step gradient allowing for the simultaneous determination of both racemic enantiomers. Detection limits of the method were 0.03 mg/L for both diclofop-acid enantiomers and 0.14 and 0.15 mg/L for diclofop-methyl enantiomers, respectively. The two-dimensional method involves the use of two chromatographs in one achiral-chiral coupling. The LC−LC method is more suitable for complex samples because it involves an online cleanup effect. Detection limits were 1.25 and 1.87 mg/L for diclofop-acid and 2.70 and 3.02 mg/L for diclofop-methyl enantiomers, respectively. Accuracy, repeatability, and reproducibility have been studied in standard samples and a technical product.