Article Title

Determination of amitraz residue in fruits by high performance liquid chromatography


A high performance liquid chromatographic method (HPLC) for the determination of amitraz residue in fruits has been developed. Twenty grams of sample and 2 g of sodium hydrogen carbonate were weighed and homogenized with acetone. After vacuum filtration, 1 g NaCl was added and partitioned with n-hexane containing 20% ethyl acetate. The organic layer was evaporated to 5 mL and applied on a florisil cartridge. The cartridge was eluted with 10 mL n-hexane:ethyl acetate (8:2, v/v), and the eluate was evaporated to dryness. The residue was dissolved in acetonitrile and determined by HPLC equipped with a UV detector. Separation was conducted with a Lichrosorb RP-18 column using acetonitrile: H2O (80:20, v/v) as mobile phase to separate amitraz and interferences, and amitraz was determined at 313 nm wavelength. Recovery studies were carried out by spiking the amitraz standards to the levels of 0.25-0.75 ppm in apples and 0.1-0.3 ppm in grapefruit. The average recoveries were 88.8-92.1% and 87.2-90.9% for apples and grapefruit, respectively. The detection limit was 0.02 ppm.

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