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A method based on a ReproSil 100 C18 column without any ion pairs or buffer additives is proposed for the determination of polar aminoglycosides.

An analytical method was developed for determination of multipesticide residues, including organophosphorus, organohalogen, pyrethroid, and organonitrogen, in tea at trace levels by GC coupled with triple quadrupole mass chromatography (QqQ-MS/MS). Scan time was selected in order to optimize QqQ-MS/MS conditions. The key parameters for controlling cleanup performance were optimized, including SPE cartridge type and elution solvent volume. Acetonitrile was the extraction solvent, and a novel multilayer SPE cartridge, Cleanert TPT, was used in the cleanup step. The recoveries of the studied pesticides at 5.0, 10.0, and 25.0 microg/kg were in the range of 77.8 to 103.8% with an RSD of less than 14%. Determination coefficient (R2) values between 0.9951 and 0.9998 were obtained for all target compounds. The LOD was between 0.002 and 1.0 microg/kg, and LOQs were 0.0066-3.3 microg/kg, which satisfied the maximum residue limits for pesticides in tea recommended by the European Union and Japan. The optimized method was applied to the analysis of real tea samples obtained from the local market.

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