Simultaneous determination of various pesticides in fruit juices by HPLC-DAD

A suitable method for the simultaneous determination of four fungicides (folpet, chlorothalonil, quinomethionat, tetradifon) and one herbicide (trifluralin) in fruit juices has been developed. The method involves the preconcentration of 25 g fruit juice samples through C-18 solid-phase extraction cartridges. The pesticides were separated and quantified by reversed-phase high-performance liquid chromatography with UV-diode array detection at 220 and 260 nm. Analytical separation was performed using a concave gradient elution with acetonitrile and water on a C-18 column. Recoveries from spiked apple, cherry juices and peach nectar, ranged from 93.8% to 99.5% and relative standard deviations were less than 3.4% in the concentration range of 1-16 mug/kg. The limits of detection for pesticides investigated are in the range of 0.5-1 mug/kg and the calibration curves showed good linearity >0.9988. The developed method has been tested on canned pure apple, cherry juices and peach nectar manufactured in Turkey. Results of this study showed that these samples analyzed contained no detectable residues. (C) 2004 Elsevier Ltd. All rights reserved.