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.

To screen the illegal substances in fishery inputs,we established the database including the precursor and the daughter ions for these possible components by the quadrupole/orbit-trap mass spectrometer,and the retention time of each drug on the same chromatographic column.And then,the extracted and diluted samples were analyzed and the components in the real samples were identified under the same conditions.Chromatographic analysis was performed on an Accucore RP-MS column (100 mm × 2.1 mm,2.6 μm) using gradient elution with 0.1％ formic acid in water and 0.1％ formic acid in acetonitrile as mobile phase.Elutes were ionized through heatable electrospray ionization (HESI) in both positive and negative mode simultaneously.Data acquisition was conducted by Full-scan ddMS2 (TopN) mode,in which the full mass profile for a continuous precursor ion injection and the fragments of each high abundant precursor of targeted were acquired with excellent time and mass resolution.Screening was carried out through comparison of the information of real samples with that of standards in the database,which were processed by software (Tracefinder).The Quantification of each component was analyzed based on the precursor ion chromatography acquired by orbit-trap mass spectroscopy,which showed a good linearity between 0.01-1 μg/mL,with R＞0.98.The method was validated by checking its minimum screening concentration (0.5 mg/L for drugs and 5 mg/L for feedstuffs) and evaluating the recovery after addition of the standard mixture in real samples (＞50％,under the addition of 10 and 100 mg/kg).The results for 68 practical samples demonstrated the effective performance of this method for screening with high-throughput,rapidness and acceptable minimum screening concentration and accuracy,in which 15 of 29 fishery drug samples were screened out for positive components that were not indicated in their labels.