Comparison of extraction techniques for the recovery of veterinary drug residues from animal tissues.
Four different techniques for the extraction of veterinary drugs were compared. The use of a high speed mixer/emulsifier, an ultrasonic bath, a Stomacher and an end-over-end mixer were used to extract both incurred and fortified residues of chlortetracycline, sulphadiazine and flumequine from chicken muscle. For each drug, similar analytical recoveries from fortified muscle samples were obtained using each of the extraction techniques. However, for each analyte the highest drug concentration detected in incurred samples was obtained following preparation using a mixer/emulsifier extraction. Residue concentrations obtained using sonication, Stomacher or end-over-end mixer procedures were as low as 20% of those obtained using the mixer/emulsifier. This highlights the need to measure both incurred and spiked samples during method validation. A survey of published methods indicated that 75% of laboratories use some form of high-speed homogenization for the extraction of drug residues from tissue. However only 52% reported detection of incurred residues. More than two-thirds of methods that used other forms of extraction did not measure incurred residues. The use of such methods has implications for the statutory detection of veterinary drug residues.
McCracken
R J
RJ
Veterinary Sciences Division, Department of Agriculture and Rural Development, Stoney Road, Stormont, Belfast, BT4 3SD, UK.
Spence
D E
DE
Kennedy
D G
DG
D042462:4-Quinolones; D000704:Analysis of Variance; D000818:Animals; D000890:Anti-Infective Agents / Q000302:isolation & purification; D002645:Chickens; D002751:Chlortetracycline / Q000302:isolation & purification; D004350:Drug Residues / Q000302:isolation & purification*; D013411:Sulfadiazine / Q000302:isolation & purification; D019155:Veterinary Drugs / Q000302:isolation & purification*
D042462:4-Quinolones; D000890:Anti-Infective Agents; D019155:Veterinary Drugs; D013411:Sulfadiazine; D002751:Chlortetracycline