ABSTRACT
Objective To investigate the pollution levels of six indicator polychlorinated biphenyls (PCBs) in animal-derived foods in Hebei Province. Methods A total of 96 food samples (including beltfish, snakehead, egg, pork liver, pork and beef meat) were collected from Hebei Province in 2019. The contents of six indicator PCBs (PCB 28, PCB 52, PCB 101, PCB 138, PCB 153 and PCB180) in different food samples were determined using isotope dilution-high resolution gas chromatography-high resolution mass spectrometry (HRGC-HRMS). Results The contents of indicative PCBs in fish samples ranged from 0.12 to 0.32 ngg-1 fresh weight, while the content of PCBs in other samples ranged from 0.11 to 1.10 ng g-1 fat. PCB 138 and PCB 153 were the main compounds detected in fish samples, while PCB 28 and PCB 52 were the main compounds detected in other samples. The average estimated daily dietary intake of PCBs for residents in Hebei Province was 0.14 ng kg-1·bw-1·d-1, and the highest contribution rate was beltfish (61.52%). Conclusion The pollution levels of indicator PCBs in animal-derived foods in Hebei Province are relatively low, and the residents has lower health risks through dietary intake of indicator PCBs.
ABSTRACT
In order to compare the standards for quinolone residues in animal-derived food in China and supervision among multiple regulatory sectors， we summarized and compared the current standards for the limits of quinolone residues in animal-derived food in China and sampling examination strategy among regulatory sectors. There were defects in the standard limits of lomefloxacin， pefloxacin， ofloxacin， and norfloxacin which have been banned by the Ministry of Agriculture and Rural Affairs. In addition， the determination limits of those indexes in the supervision remain inconsistent across multiple regulatory sectors. Multiple regulatory sectors on food safety should perform further risk assessment on the above problems and formulate the standards for the limits of quinolone residues in animal-derived food that may be applicable in China.
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Objective:To establish a determination method for sulfadoxine, sulfathiazole and sulfadiazine in animal derived prod-ucts by ultra-performance liquid chromatography-tandem mass spectrometry ( UPLC-MS/MS) . Methods:Trichloroacetic acid and ace-tonitrile were used in the extraction and removal of proteins. A Waters Acquity UPLC BEH C18 (100 mm × 2. 1 mm,1. 7 μm) column was used as the separation column. The mobile phase was 0. 1% formic acid in water-methanol with gradient elution. The three sulfona-mides residues were detected with multiple reaction monitoring( MRM) mode in multi-period. Results:Under the conditions,the linear range of sulfadoxine, sulfathiazole and sulfadiazine was 1. 0-200. 0 ng·ml-1 ,the linear correlation coefficient was above 0. 99,the re-covery was more than 70%,the detection limit was 0. 5 ng·ml-1 , and the quantification limit was 1. 0 ng·ml-1 . Conclusion: The sample preparation method is simple and fast, and the method can be used to analyze sulfadoxine, sulfathiazole and sulfadiazine in ani-mal derived food efficiently and sensitively.
ABSTRACT
An automated analytical method for simultaneous determination of vitamin A and E in livers, fortified infant formulae and eggs has been developed based on on-line solid phase extraction (SPE) coupled with a dual gradient high performance liquid chromatography system with column-switching. Firstly, food samples were centrifuged after saponified in mixture solution of anhydrous alcohol, potassium hydroxide and ascorbic acid at 80 ℃ for 30 min. Secondly, the saponified sample was loaded and washed on the first dimension extraction column using methanol-water (60∶40, V/V). Afterwards, the targeted analytes were trapped and enriched on the SPE column. Finally, the trapped analytes were transferred to the second dimension analysis column by valve-switching technique for the following separation and determination. Several key factors such as the type of SPE columns, elution buffer as well as pH of washing solution were optimized. The results showed that the calibration curves of vitamin A and E were linear in the range of 0 . 02-20 mg/L with correlation coefficient (R2) more than 0. 9998. In addition, the limits of detection (S/N=3) were found in the range of 3. 0-30. 0 μg/L. The spiked recoveries of the vitamin A and E from livers, eggs and fortified infant formulae ranged from 87 . 3% to 115 . 0% with the relative standard deviations ( RSDs ) of 1 . 8% -4 . 6%. The developed method is simple, sensitive and rapid to determine vitamins A and E in animal derived food.