Detection and identification of zeranol in chicken or rabbit liver by liquid chromatography-electrospray tandem mass spectrometry.
A sensitive, specific, and reliable liquid chromatography tandem mass spectrometry (LC-MS/MS) method was developed for detection and identification of zeranol in chicken or rabbit liver. A homogenized liver sample was hydrolyzed with beta-glucuronidase/arylsulfatase, and the hydrolysate was extracted with ethyl ether. The supernatant was evaporated to dryness, and the residue was dissolved in chloroform and re-extracted with sodium hydroxide. After acidification, the extract was cleaned up on a C18 solid-phase extraction cartridge and analyzed by electrospray LC-MS/MS in the negative ion mode. The multiple reaction monitoring transition from both m/z 321 to 277 and m/z 321 to 303 was monitored for confirmation, and the product ion of 277 was used for quantitation. Separation was performed on a Waters XTettra C18 column (50 x 2.1 mm, 3.5 microm) combined with a safeguard column (Symmetry C18, 20 x 3.9 mm, 5 microm), using a gradient elution with acetonitrile and 20 mM ammonium acetate. Calibration curves were prepared and good linearity was achieved over the concentration ranges tested. For all liver samples fortified at 3 different levels of 1, 5, and 50 microg/kg, the overall recoveries and relative standard deviations were in the range of 61-90 and 8-13%, respectively. The limit of quantitation based on the assay validation was 1 microg/kg. The method had been used on a routine basis for detection and identification of zeranol in liver samples.
Technical Center for Animal, Plant and Food Inspection and Quarantine, Shanghai Exit-Entry Inspection and Quarantine Bureau, China. xfang@public1.sta.net.cn
Xiaoming
X
Fang
Jiahua
J
Chen
Dehua
D
Guo
Guoquan
G
Wang
D000818:Animals; D002645:Chickens; D002853:Chromatography, Liquid / Q000379:methods; D004968:Estrogens, Non-Steroidal / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism; D005506:Food Contamination / Q000032:analysis; D008099:Liver / Q000737:chemistry*; D011817:Rabbits; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D015029:Zeranol / Q000032:analysis* / Q000737:chemistry / Q000378:metabolism
D004968:Estrogens, Non-Steroidal; D015029:Zeranol