|LAI, GUOXIN - Meizhouwan Vocational Technology College|
|CHEN, TUANWEI - Fujian Agricultural & Forestry University|
|LI, QIONGQIONG - Shanghai Institute For Food And Drug Control|
Submitted to: Journal of Food Analytical Methods
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 12/15/2014
Publication Date: 1/22/2015
Publication URL: http://handle.nal.usda.gov/10113/60722
Citation: Lai, G., Chen, G., Chen, T., Li, Q. 2015. Rapid screening of oxytetracycline residue in catfish muscle by dispersive liquid-liquid microextraction and europium-sensitized luminescence. Journal of Food Analytical Methods. DOI: 10.1007/s12161-014-0076-4.
Interpretive Summary: Catfish farming is significant in southern states of the US. The Food and Drug Administration (FDA) approved oxytetracycline (OTC) usage in catfish and set tolerance at 2 parts per million (ppm). A rapid method was developed to screen presence of OTC antibiotic in catfish muscle. After extraction, cleanup was carried out by dispersive liquid-liquid microextraction (DLLME), and detection followed by europium-sensitized luminescence (ESL). Using samples of varied subspecies and origins, a threshold was derived from 20 samples spiked at 2 ppm, and applied to randomly spiked samples at 0-4 ppm OTC. Among 49 samples, 43 were classified correctly except 6 negatives were presumed positives. This reliable, and low-cost method reduced harmful organic solvents, eliminated solid phase extraction, and significantly improved productivity.
Technical Abstract: Oxytetracycline (OTC) residue in catfish muscle was screened by dispersive liquid-liquid microextraction (DLLME) and europium-sensitized luminescence (ESL). After extraction in EDTA, HCl, and acetonitrile, cleanup was carried out by DLLME, and ESL was measured at microgram = 385 nm and wavelength = 620 nm using a portable fluorometer. The screening threshold was set at T=x-3sigma2, where x2 and s2 were mean and standard deviation of twenty catfish muscle samples spiked at 2 ug/g, the tolerance set by Food and Drug Administration. Among 49 samples randomly spiked with OTC at 0-4 ug/g, 43 were screened correctly without false negative, but 6 negatives were classified as presumptive positives. This rapid, reliable, and low-cost method reduced usage of chlorinated solvents, eliminated solid phase extraction, and significantly improved sample throughput.