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Screening by testing conditions, the extraction system, the establishment of a high-performance liquid chromatography (HPLC)-based diflubenzuron standard wheat residue analysis method, and the method sensitivity, accuracy and precision. analyzed to investigate the stability of the standard solution, the sample extract and sample diflubenzuron, and study the applicability of the method in a matrix of soybean, wheat, and peanuts. Main results are as follows: 1. HPLC Conditions: C18 Thermo Hypersil-ODS reversed phase column, 4.6 mm (id) x 250mm, mobile phase: acetonitrile / water (60/40, V / V), flow rate: 1.0 mL / min, detection wavelength: λ = at 254 nm, column temperature: 30 ° C, the injection volume: 20 μL, the retention time of about 7.9 min. Under this condition, it is possible to diflubenzuron accurate qualitative and quantitative. Screening extraction method of extraction system: mechanical oscillation and ultrasonic oscillation extraction wheat diflubenzuron average recovery were 89.37% and 80.60%, extraction methods optimized for mechanical oscillation method. Extraction solvent: acetone, ethyl acetate, dichloromethane and acetonitrile wheat Diflubenzuron average recovery were 91.27%, 72.12%, 89.37% and 90.55%, optimized extraction solvent is acetonitrile. Extraction time: mechanical oscillation extraction of 40, 60 and 80min diflubenzuron wheat average recoveries were 68.15%, 81.97% and 82.45%, respectively, the optimized extraction time of 60 min. Extraction times: once, twice and three times extracted wheat diflubenzuron average recoveries were 81.97%, 89.37% and 91.26%, respectively, the optimized extraction times for the two. 3. Recovery experiments and method sensitivity, accuracy, precision experiments were added in the wheat 0.04mg · kg -1 , 0.2mg · kg -1 (MRL 4.15,2.37% and 3.37%) -1 diflubenzuron standard solution and 1.0mg · kg, the average recoveries were 90.87%, 89.37% and 90.25%, coefficient of variation were %, respectively, to meet the requirements of the pesticide residue analysis. Wheat diflubenzuron minimum detectable concentration of 0.04mg · kg -1 . Matrix applicability of the experimental method with optimized soybean, rice, Anqing, Lu'an wheat add 0.2mg · kg -1 Add recovery experiment measured the average recoveries of respectively 88.75%, 90.13%, 92.10% and 84.15%, coefficient of variation of 3.96%, 2.18%, 2.26% and 1.98%, respectively. The results prove that the optimized method is equally applicable to the above matrix, and meet the requirements of pesticide residue analysis. Stability experiments at -20 ° C, 4 ° C and 25 ℃ condition after 90 days of storage, the decomposition rate of diflubenzuron in acetonitrile were 0.49%, 2.19% and 4.78%, indicating that diflubenzuron standard working solution Diflubenzuron good stability; wheat extract at -20 ° C, 4 ° C and 25 ℃ conditions after 30 days of storage, the decomposition rate of 1.97%, 2.10% and 3.38%; wheat diflubenzuron - 20 ° C, 4 ° C, 25 ° C under the conditions of storage for 10 days, good stability, residual rate of more than 99%, storage 60 days after the decomposition rate of 2.18%, 3.03% and 4.15% respectively. 6 Quality control experiments this article were on the accuracy and precision of the method of quality control analysis, the results show that the accuracy and precision in 0.2mg kg -1 Add level are in control , effective results. The advantages of the method of this article as a single-residue analytical methods in the overall simple procedure takes less time, a small amount of solvent used, good reproducibility. Matrix method has strong applicability, the method is suitable for soybean and rice matrix of diflubenzuron residue analysis.
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