Development Of A High-Performance Liquid Chromatographic Method For Determination Of Residual Diflubenzuron And Triflumuron In Greasy Wool

Both diflubenzuron and triflumuron are benzoylurea insect growth regulators and their residues in greasy wool have negative effect on people’s health as well as the environment. However, as a country consuming and importing huge amounts of wool, China is unable to take effective measures to control the increasingly serious problem of excess diflubenzuron and triflumuron in imported greasy wool due to inavailability of standard methods for detection of diflubenzuron and triflumuron in wool. Thus, this thesis focused on developing a high-performance liquid chromatographic method for determination of residual diflubenzuron and triflumuron in greasy wool.The chromatographic conditions of determining diflubenzuron and triflumuron were firstly studied. It was found that with the mobile phase being set at acetonitrile/water （41: 59,v/v）, good resolution between the two benzoylureas and the wool matrices was achieved on C₁₈ column and the peaks of the two benzoylureas were no longer interfered with, thus this mobile phase was applied to the analysis of diflubenzuron and triflumuron in wool. Other chromatographic conditions selected were as follows: column—XTerra MS C₁₈（150×3.9mm i.d., 5μm）, UV detection wavelength—254nm, flow rate—1.0mL/min, column temperature—30℃, injection volume—10μL.Subsequently, the pretreatment methods for wool samples were explored. After assessing different extraction solvents, preliminary cleanup strategies and solid-phase extraction （SPE） cartridges, we chose dichloromethane as the solvent for Soxhlet extraction of wool samples and by changing the solvent to methanol after extraction, most wool matrices were successfully eliminated before SPE cleanup. And finally, diflubenzuron and triflulnuron were quantitatively recovered on the LC-Alumina-N cartridge, while wool matrices were selectively removed.The method we developed had good accuracy, precision and linearity. Mean recoveries for diflubenzuron and triflumuron from wool samples spiked at 1, 2, 4mg/kg were 79.9%-100.4%, with relative standard deviations lower than 10%. The detection limits for the two benzoylureas in wool were both 0.03mg/kg and the quantification limits were both 0.1mg/kg, all of which were sufficient for routine residue analysis. In the Inter-laboratory Pesticide Residue Proficiency Testing Program on greasy wool held by the Department of Agriculture of Australia, satisfactory data were gained with our method, demonstrating the reliability and applicability of the method we established.