Analysis Of Optical Isomers Of Flutriafol, Tebuconazole And α-Halogenated Acids By Precolumn Derivatization Chromatograhpy

General enantiomers have the difference in biological activity, for example, most of triazole fungicides have the fungicidal and plant growth regulating activities stimultaneously, and the difference in biological activity is evident. If they are to be used in racemates, phototoxicity will be happened easily, and their use areas are limited (for example, they can't be used as seed dress agent). So it's need to analyse the compositions of enantiomers and ensure proportion of optical isomers. In this thesis, the precolumn derivatization chromatography was applied to separate and analyse optical isomers of flutriafol , tebuconazole and two α-halogenated acids α-bromopentanoic acid and α-chloropropionic acid.A method of determining the optical isomers of flutriafol by precolumn derivatization and chromatography assay was established. Firstly' thionyl chloride and S-(-)-2-(4'-chlorophenyl) isovaleric acid reacted to give a acyl chloride, this compound reacted with racemic isomers sodium flutriafol to produce a pair of diastereoisomers. Then the derivatives were separated on high-performance liquid chromatography with Lichrospher SI column and gas chromatographicy with HP-5MS capillary chromatography column. The results indicated that the S/R ratios of 96.10% flutriafol sample was 1.63, and the higher activity R- flutriafol content was 36.5%. The structure of derivatives of flutriafol was confirmed by GC-MS spectra.At the same time, the precolumn derivatization and chromatography assay method was established to determine the optical isomers of tebuconazole. First, thionyl chloride and S-(-)-2-(4'-chlorophenyl) isovaleric acid reacted to produce a acyl chloride, then this product reacted with racemic isomers tebuconazole to prepare a pair of diastereoisomers. The derivatives were separated on normal chromatography column by high-performance liquid chromatographic and gas chromatographic assay. By analysing the tebuconazole's diastereoisomers composition, it was confirmed that the S/R ratios of 99.04% tebuconazole sample was 1.37 and the higher activity S- tebuconazole content was 57.3%. Also the structure of tebuconazole derivatives was verified with GC-MS spectra.Furthermore, precolumn derivatization and chromatography assay for thedetermination of the optical isomers of α-halogenated acids was established. A acyl chloride was synthesized by the reaction of thionyl chloride and S-(-)-a-phenylethylamine, then it reacted with racemic isomers α-chloropropionic acid or α-bromopentanoic acid, and two pairs of diastereoisomers. The S/R ratios of α-halogenated acid was determined by analysing the diastereoisomers composition. The derivatives were separated on normal chromatography column by gas chromatographicy and high-performance liquid chromatography, and the results showed that the R/S ratios of α-chloropropionic acid was 1.03, and the R/S ratios of α-bromopentanoic acid was 1.06. And the R/S ratios of resoluted a-Bromopentanoic acid was 3.75, which the S-(-)-isomer was dominant. GC-MS spectra was applied to confirm the structure of derivatives.