Determination of Metalaxyl in Water Melons and Bananas by HPLC

A method for determination of metalaxyl (MEL) in water melons and bananas have been developed by automatic solid-phase extraction (SPE) coupled with high performance liquid chromatography (HPLC). Samples were firstly extracted by acetonitrile and then homogenized, filtrated, automatic solid-phase extraction (SPE), finally purified by C18 column. The experiment was carried on SunFireTM C18 column with the mobile phase of acetonitrile-water-methanol (25∶40∶35, by vol) at the flow rate of 1.0 mL/min. The detection wavelength and injection volume were set at 220nm and 10uL respectively. The recoveries of three different concentration (0.02, 0.20, 1.00 mg/kg) for water melons and bananas were between 94.3%~101.0%and 81.5%~99.6%, respectively. RSD (n=5) were 1.30%~5.29%and 2.66%~6.67%, respectively. The lower detection limit for metalaxyl (MEL) was 0.006mg/kg. This method met with the requirements of the pesticide residue detection.