ABSTRACT
Gaschromatography-tandemmassspectrometrywasadoptedtoidentifythehydroxylatedmetabolites of polychlorinated biphenyls and analyze the target compounds in fishery products. After the silylation derivatizaiton at 60 ℃ for 40 min, the MS spectrum of derivatives was obtained by GC/MS/MS under fullscan mode, and the fragment ions with the highest relative abundance were identified as m/z 399, 399, 399, 399, 399, 448 and 469, respectively which were defined as the precursor ion for product ion scan. The MS/MS spectrum was obtained under multiple reaction mode ( MRM ) by GC/MS/MS. And the product ions corresponded with the precursor ions were m/z 364, 364, 364, 364, 364, 433 and 434, respectively. The target compounds can be identified accurately by GC/MS/MS. In the present study, we took seven hydroxylated polychlorinated biphenyls as target compounds including 3-OH-PCB101 , 4-OH-PCB106 , 4-OH-PCB112 , 4'-OH-PCB101 , 3-OH-PCB118 , 3-OH-PCB138 and 3-OH-PCB180 . According to the identification method stated as above, the MS and MS/MS spectra of seven compounds were obtained. The compounds can be qualified and quantified by the identification method. The limits of detection ranged from 0. 02 to 0. 14 μg/L, and the limits of quantification ranged from 0. 09 to 0. 48 μg/L. The method has been applied to identify the hydroxylated polychlorinated biphenyls in fishery products.
ABSTRACT
Objective:To generate monoclonal antibodies against ciprofloxacin (CIP) and to analyze its immunological traits for establishing a determination method for ciprofloxacin residues in food tissues.Methods:BALB/c mice were immunized by the conjugation of CIP-BSA successfully.The splenic cells of BALB/c mice and the oncocyte were fused and screened in HAT culture medium.Cell strains of 1C9,3F6,6H2,6A7,6G11 and 8F5 were cloned,which could secret the monoclonal antibody (Mab) for ciprofloxacin.Results:By ELISA method,the haplotype of Mabs were identified.The antibody secreted by 1C9,3F6 and 6A7 were classified to the IgG2a.Those of 6H2 and 8F5 were classified to the IgG1 while 6G11 to IgG3.The results of SDS-PAGE showed that the Mab protein was made up of the weight chain and the light chain whose molecular weight were 50 kD and 25 kD,respectively.All of those Mabs had fine specificity and sensibility.The indirect ELISA titer of 1C9 was 1:6.4?102 in supernatant and 1:5.6?105 in ascites.The affinity of 1C9 was 2.85?109 L/mol and the value of IC50 reached to 245.86 ng/ml.The protein secreted by 1C9 was screened for establishing the ELISA method and the detective limitation reached to 45.25 ng/ml.There were no cross reactions to Ofloxacin,Difloxacin,Sarafloxacin,Malachite green,Chloramphenicol and Furacilin while the rate of cross reaction to Enrofloxacin could reach to 84.6%.Conclusion:The Mabs are sensitive and specific,which are suitable to be applied in establishing immunoassay of CIP residues.