Analysis Of Residues And Dynamic Of Oinxe-copper And Kasugamycin In Watermelon

Watermelon has been worldwidely planted for its high nutritional value and great medicinal efficacy. China has the largest watermelon cultivating area all over the world, meanwhile, watermelon was also one of the most important economic crops to China. However,the infection of diseases such as downy mildew,anthracnose and bacterial spot disease caused the decrease of production as well as the extensive usage of pesticides. With people’s emphasis on food safety recently,using low toxic pesticides during the planting is becoming a popular treandency. Oxine-Copper and Kasugamycin were environmentally friendly pesticides,they could provide good prevention against the main pathogenic bacteria for watermelon by a lower toxicity than other pesticides. Meanwhile, the threat on watermelon’s edible safety environment contamination they caused would be far more less than normal pesticieds. However, Oxine-Copper and Kasugamycin cannot be used in practical planting since the dynamic resolution and application rules were not determined yet. Therefore, experiment on dynamic resolution and final residue of Oxine-Copper and Kasugamycin in watermelon will not only provide essential basis for the national MRL,but also make a great significance on pesticide implementation and the watermelon’s quality safe.1. We optimized the chromatogram condition of Oxine-Copper,chose the suitable chromatographic column,mobile phase conditions,and successfully established a UPLC detection method for the target. In this chromatogram condition, oxine-copper was separated well and correlation coefficients were greater than 0.999.2. Analysis of residues of oxine-copper on watermelon using SPE sample preparation and ultra performance liquid chromatography. Under the experimental conditions, the average recoveries of oxine-copper were between 78.6 % and 96.1 % in the spiked level of 0.05、0.5、2.5 mg·kg-1 in blank samples of watermelon and soil,the coefficient of variation between 0.2 % and 6.5 %,the minimum detectable amount was 0.5 ng,the minimum detectable concentration of oxine-copper were 0.05 mg?kg-1 in watermelon and soil. Analysis of residues of kasugamycin on watermelon using ultra performance liquid chromatography mass spectrometry. Under the experimental conditions, the average recoveries of kasugamycin were between 78.3 % and 100.4 % in the spiked level of 0.01、0.025、0.05 mg?kg-1in blank samples of watermelon and soil,the coefficient of variation between 2.5 % and 10.5 %, the minimum detectable amount was 0.1 ng, the minimum detectable concentration of kasugamycin were 0.01mg?kg-1.3. The degradation test of 45 % oxine-copper and kasugamycin WP( the oxine-copper 40 %,kasugamycin 5 %) was carried out watermelon fields at Shandong Jinan and Anhui Suzhou in 2013 and 2014. The results showed that the degradation of oxine-copper and kasugamycin followed an equation of one-grade chemical reaction dynamics in the watermelon and soil. The degradation half-life of oxine-copper in ranged from1.5d to 1.7d in watermelon and 1.1d to 2.1d in soil. The degradation half-life of kasugamycin in ranged from 0.9d to 1.1d,and 1.0d to 1.3d in soil.4. 45 % oxine-copper and kasugamycin WP( the oxine-copper 40 %,kasugamycin 5 %) of reasonable guidelines for the use of watermelon was developed. 45 % oxine-copper and kasugamycin WP was used to control bacterial spot disease and watermelon anthracnose,1125 g/ha(the concentration of active ingredient: oxine-copper is 455.63 g a.i./ha and kasugamycin is 50.6 g a.i./ha) was applied, sprayed 2 times, the safe interval of 7d. The final residue of oxine-copper was lower than 0.05 mg?kg-1 and kasugamycin was lower than 0.01 mg?kg-1.