Extraction and liquid chromatographic analysis of sulfadimethoxine and 4-N-acetylsulfadimethoxine residues in channel catfish (Ictalurus punctatus) muscle and plasma.
A simple and rapid method was developed for the simultaneous extraction and liquid chromatographic (LC) determination of sulfadimethoxine (SDM) and 4-N-acetylsulfadimethoxine (N-acetyl SDM) in channel catfish muscle and plasma. Tissues fortified at 0, 50, 100, 200, 400, and 1000 ppb were examined. Matrix solid phase dispersion (MSPD) was used for muscle extraction. Plasma was extracted with a modified MSPD procedure in which 100 microL plasma and 400 mg C18 were blended by Vortex mixing in a disposable chromatographic column. Recovery of SDM based on radioactivity was 79% for muscle and 67% for plasma. Standard curves based on extracted fortified samples were used for quantitation of N-acetyl SDM. LC run times of 12 min were obtained using a microbore analytical column and an isocratic mobile phase of aqueous 0.017M phosphoric acid-acetonitrile at ratios of 71:29 for muscle and 73:27 for plasma extracts. Method detection limits were 26 ng SDM and 26 ng N-acetyl SDM/g muscle, and 33 ng SDM and 11 ng N-acetyl SDM/mL plasma. Intra-assay variation was < 10% for both compounds at all concentrations examined. Inter-assay variation for SDM was 13% for muscle and 14% for plasma, and for N-acetyl SDM was 11% for muscle and 10% for plasma.
Walker
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CC
Louisiana State University, School of Veterinary Medicine, Department of Veterinary Physiology, Pharmacology, and Toxicology, Baton Rouge 70803-8420.
Barker
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SA
D000818:Animals; D002853:Chromatography, Liquid / Q000379:methods*; D004350:Drug Residues / Q000032:analysis* / Q000302:isolation & purification; D007059:Ictaluridae; D009132:Muscles / Q000737:chemistry*; D015203:Reproducibility of Results; D013412:Sulfadimethoxine / Q000031:analogs & derivatives* / Q000032:analysis* / Q000097:blood / Q000302:isolation & purification; D013997:Time Factors
C038180:N(4)-acetylsulfadimethoxine; D013412:Sulfadimethoxine