| A liquid chromatography tandem mass spectrometric method was developed for the determination of benzimidazole fungicides and their metabolites such as thiophanate-methyl(TM),2-aminobenzimidazole(2-AB),carbendazim(MBC),triabendazole(TBZ),5-hydroxy-triabendazole(5-OH-TBZ) in 7 types of concentrated fruit juices including apple,mango,pineapple,pear,orange,lychee and passion fruit.Seven representative concentrated fruit juices were selected and extracted with acetonitrile.The extracts were purified with PSA column.The separation of 5 analytes was carried out on a ZORBAX Eclipse XDB-C18 column using methanol-10 mmol/L ammonium acetate(containing 0.1% formic acid) as mobile phase by gradient elution.The detection of analytes was performed by electrospray tandem mass spectrometry with ES+ and multiple reaction monitoring (MRM) modes.The results showed that,the method showed good linear relationships in the range of 0.02 -0.2 mg/L for the tested samples,with correlation coefficients no less than 0.998 5.The quantitation limits were 2.0 μg/kg for 2-AB and 5-OH-TBZ,and 1.0 μg/kg for the rest of the analytes.The
mean recoveries ranged from 70% to 110% with relative standard deviations of 0.1%-10.9% when the fortified levels for 2-AB and 5-OH-TBZ were 2,4,20 μg/kg and those for TBZ，MBC，TM were 1,2,10 μg/kg,respectively.The proposed method was sensitive and reliable,and was successfully applied in the determination of benzimidazole fungicides and their metabolites in real commercial concentrated juices. |