Preparation Of Azoxystrobin Microcapsules And Research Of Their Target Deposition

Safety and effectiveness are two sides that pesticides pay more attention to.The run-off of pesticide deposition on target crop brings about adverse effect on the food quality eco-environmental security and human health risk. How to reduce the run-off of pesticide on spraying and improve the deposition and efficiency of pesticide has been paid great attentions all the time. The factors of influence targeting deposition of pesticide were discussed and we researched four different particle sizes microcapsule, different spray volume, different spray adjuvants to targeting deposition of pesticide on target crop by using Azoxystrobin microcapsule as model drug, typical hydrophilic cucumber leaf and typical hydrophobic rice leaf as model target crop, stable and high ratio of recovery Allura Red as tracer, siphon type nozzle to spray. It was aimed at providing theoretical support to reduce run-off pesticide and improve targeting deposition.1. A method was established for determination of six glycol ethers in liquid pesticide formulation. Cyclohexane was used as internal standard(IS). Capillary column Agilent DB-5 was used as separation column and flame ionization detector(FID) as detection.The results showed that the method’s detection period was moderate, linearity correlation coefficient was all above 0.9991, the relative standard deviations were 0.34%~0.87% and recoveries of six harmful solvents ranged from 91.40%~98.03%.The methods which is simple, rapid, accurate and feasible can be applied to determination of glycol ethers harmful solvent in liquid pesticide formulation.2. Four different particle sizes Azoxystrobin microcapsule were prepared by emulsion/solvent evaporation using ethyecellulose as wall materials and had well-defined spherical shape, high encapsulation efficiency and drug loading capacity.The water-dilluted solution system of four different particle sizes Azoxystrobin microcapsule were evaluated of wettability. The particle sizes of microcapsule have no appreciable influence on surface tension of water-dilluted solution system, contact angle and the maximum retention on cucumber leaf and rice leaf in adding organosilicone adjuvants S903 and plant oil adjuvants Tmax. But the wettability of water-dilluted solution was obviously improvement by adding organosilicone adjuvants S903 and plant oil adjuvants Tmax. Surface tension of water-dilluted solution system and contact angle on cucumber leaf and rice leaf decreases with the increasing of concentration of additives added. The maximum retention of water-dilluted solution on cucumber leaf and rice leaf has a lot to do with wettability of water-dilluted solution, it is the most beneficial to wetting and deposition of water-dilluted solution on target crop when the surface tension of water-dilluted solution thinner than critical surface tension of target crop.3. The study of four different particle sizes microcapsule water-dilluted solution’s targeting deposition on cucumber leaf and rice leaf. The deposition of Allura Red and Azoxystrobin in pesticide water-dilluted solution increased first, when to lose point, decreased and then achieved a balance, with the increasing of spray time(spray volume).The results showed that added different type spray adjuvants can influence the lose point and the maximum retention of pesticide water-dilluted solution on the cucumber leaf and rice leaf. In our study, organosilicone adjuvants S903 can reduce the lose point and the maximum retention of four different particle sizes microcapsule water-dilluted solution on the cucumber leaf, plant oil adjuvants Tmax can improve the lose point and the maximum retention. The two spray adjuvants both can improve the lose point and the maximum retention of four different particle sizes microcapsule water-dilluted solution on the rice leaf, then influence the spray time to the lose point and the maximum retention,therefore, we should determine the spray volume based on the different target crop and different spray adjuvants type. Azoxystrobin microencapsulation cann’t improve the deposition of Allura Red and Azoxystrobin in the water-dilluted solution,in other words, it cann’t improve the deposition of pesticide water-dilluted solution and pesticide formulate. Deposition of Allura Red and Azoxystrobin in the water-dilluted solution have no obvious difference between the four kinds of particle size Azoxystrobin microcapsule.