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摘要:
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In this study, we developed an analytical method for determination of five pesticides (formetanate, acetamiprid, metalaxyl, dimethomorph, fenpyroximate) using micellar electrokinetic chromatography (MEKC). A 70 cm capillary(60 cm in effective ) with I.D. 75 μm, O.D. 375 μm was used in this study. The optimization separation conditions for MEKC were using a 5.0 mM phosphate buffer (pH 8.0) containing 0.2% polyoxyethylene sorbitan monolaurate (Tween 20) with 20 mM hexadecyltrimethylammonium bromide (CTAB). UV detector was set at 228 nm, and the applied voltage is -12.5 kV. Under these conditions, the pesticides were separated in 16 min and the detection limit (S/N = 3) of formetanate, acetamiprid, metalaxyl, dimethomorph, fenpyroximate were 0.35, 0.12, 0.84, 0.15, and 0.41 µM, respectively. The linear ranges of the five pesticides were from 3 μM to 30 μM for formetanate、1 μM to 30 μM for acetamiprid and dimethomorph、3 μM to 40 μM for metalaxyl、3 μM to 50 μM for fenpyroximate, R2 all larger than 0.986. This method was successfully applied to analyze the pesticides in chrysanthemum powder sample. The results revealed that the recovery of three pesticides in chrysanthemum powder were about 85 ~ 115%.
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