| Nikkomycin, as a kind of biopesticide belong to peptidyl nucleocide antibiotics, is a competitive inhibitor of chitin synthetase. Nikkomycin is producted by biosynthesis. Product fermentation technology includes ion-exchange method and low pressure vaporize method. In this dissertation, we optimized the second technology and increased the extraction yield from 32-35% to 57-61%. The quantitative determination methods of nikkomycin usually employed microbial assay (bioassay), but the efficiency and accuracy was low, and the two ingredients nikkomycin X and Z can't be separated by conventional reverse-phase HPLC. we developed an ion-pair high-performance liquid chromatography method which shortened the analysis time and increased the relative standard deviation. We investigated the relationship between proportion of flow phase, pH of buffer, concentration of buffer, concentration of ion-pair agent and and capacity factor and finally realized baseline separation of nikkomycin X and Z. The regression equation was: Y=16627X+291874,The calibration curve was linear (r=0.9945) within the range of 31.2—250ug/ml. The mean recovery was 97% (n=6) and the precision (RSD) was 1.97% (n=8), day to day precision was 0.542%. we studied the stability of three formulations of nikkomycin and found that stability of aqueous solution (AS) was poor and can't be merchandised. And we investigated the relationship between stability and kind of carriers and adjuvants of other two formulations water-soluable powder and water-soluable granule and then screened the most compatible carriers and adjuvants. The raw formulation of SP(%): active ingredient 30, carrier J 30, surface active agent S2 8.49, GS1 8.49, anti-UV agent M 10, anti-oxidation agent 0.02, desiccant 5, antiseptic (NaCl) 8. The raw formulation of SG(%): active ingredient 40, carrier C2 30, surfactant GS3 30. |
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