Development of an enzyme-linked immunosorbent assay for seven sulfonamide residues and investigation of matrix effects from different food samples.
Direct competitive enzyme-linked immunosorbent assays (ELISA) were developed to detect a broad range of sulfonamides in various matrices. Screening for this class of antibiotics in pig muscle, chicken muscle, fish, and egg extracts was accomplished by simple, rapid extraction methods carried out with only phosphate-buffered saline (PBS) buffer. Twenty milliliters of extract solution was added to 4 g of sample to extract the sulfonamide residues, and sample extracts diluted with assay buffer were directly analyzed by ELISA; matrix effects could be avoided with 1:5 dilution of pig muscle, chicken muscle, and egg extracts with PBS and 1:5 dilution of fish extract with 1% bovine serum albumin (BSA)-PBS. For liver sample, the extraction method was a little more complicated; 2 g of sample was added to 20 mL of ethanol, mixed, and then centrifuged. The solvent of 10 mL of the upper liquid was removed, and the residues were dissolved in 10 mL of PBS and then filtered; the filtrate was diluted two-fold with 0.5% BSA-PBS for ELISA. These common methods were able to detect seven sulfonamide residues such as sulfisozole, sulfathiazole, sufameter, sulfamethoxypyridazine, sulfapyridine, sulfamethizole, and sulfachlorpyridazine in pig muscle, liver, chicken muscle, egg, and fish. The assay's detection limits for these compounds were less than 100 microg kg-1. Various extraction methods were tested, and the average recovery (n=3) of 100 microg kg-1 for the matrices was found to range from 77.3 to 123.7%.
Zhang
Hongyan
H
Tianjin Key Laboratory of Food Nutrition and Safety, Faculty of Food Engineering and Biotechnology, Tianjin University of Science and Technology, Tianjin 300222, People's Republic of China.
Wang
Lei
L
Zhang
Yan
Y
Fang
Guozhen
G
Zheng
Wenjie
W
Wang
Shuo
S
D000818:Animals; D002645:Chickens; D004350:Drug Residues / Q000032:analysis; D004531:Eggs / Q000032:analysis; D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods*; D005399:Fishes; D005504:Food Analysis / Q000379:methods*; D008099:Liver / Q000737:chemistry; D008460:Meat / Q000032:analysis; D009132:Muscles / Q000737:chemistry; D012680:Sensitivity and Specificity; D013449:Sulfonamides / Q000032:analysis*; D013552:Swine
D013449:Sulfonamides