• Korean Journal of Environmental Agriculture
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• v.35 no.3
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• pp.211-215
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• 2016

BACKGROUND: The commercial biopesticides containing Chenopodium ambrosioides L. extracts which have been registered as one of the ingredients of the commercial biopesticide by the organic agriculture materials, and have been widely used in Republic of Korea. However, the quantitative analysis method of the active substances for the commercial biopesticides containing C. ambrosioides L. extract has not been conducted.METHODS AND RESULTS: To analyze the quantitative analysis of ascaridole, carvacrol, and p-cymene as active substances of C. ambrosioides L. extract, hydrophilic lipophilic balance cartridge was used for solid phase extraction. The active substances were analyzed by the gas chromatography with flame ionization detector. The limit of quantitation values of ascaridole, carvacrol, and p-cymene were 10, 5, and 2 mg/L, and the recovery rates were 96.3, 84.0, and 82.5% in liquid products and 98.3, 99.1, and 97.3% in solid products, respectively. The total content of ascaridole, carvacrol, and p-cymene in the commercial biopesticides was ranged from 0.08 to 12.75%.CONCLUSION: From these results, this method was suitable for the quantitative analysis of the active substances of commercial biopesticides containing C. ambrosioides L. extract.

• Korean Journal of Environmental Agriculture
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• v.36 no.1
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• pp.17-21
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• 2017

BACKGROUND: Castor oil and wormseed extract are important active ingredients for biopesticide, and ricinoleic acid in castor oil and three monoterpenes (ascaridole, carvacrol and p-cymene) in wormseed extract are known bioactive substances. However, their stabilities had not been studied, even though the stability was the core property for estimation of shelf-life of biopesticide. Aimed to investigate the thermal stabilities of the bioactive substances in castor oil and wormseed extracts. METHODS AND RESULTS: The contents of ricinoleic acid and three monoterpenes (ascaridole, carvacrol and p-cymene) were analyzed by gas chromatography (GC). The thermal stabilities of the bioactive substance were measured at $0^{\circ}C$, $23^{\circ}C$, $30^{\circ}C$, $40^{\circ}C$, $45^{\circ}C$ and $54^{\circ}C$ for 84 d. The half-lives of ricinoleic acid in biopesticides was ranged from 28.9 d to 57.8 d at $30^{\circ}C$, and the stability of pure castor oil were located in the range ($t_{1/2}$=46.2d for Indian product and 27.7 d for Korean product) at the same temperature. The half-lives of the total monoterpenes in biopesticides were ranged from 3.9 d to 27.7 d at $30^{\circ}C$. Among the monoterpenes, the stability ascaridole and p-cymene were decreased in acidic condition. All the bioactive substances showed similar stability on the different thermal conditions. CONCLUSION:The half-lives of most bioactive substance from castor oil and wormseed extracts were less than 100 d. To increase the stability of bioactive substance in biopesticide, stabilizing additives like antioxidant and oxygen remover should be considered to extend of the shelf-life.