SIMULTANEOUS DETERMINATION OF NITROFURAZONE, NITROFURANTOIN, AND FURAZOLIDONE IN CHANNEL CATFISH (ICTALURUS-PUNCTATUS) MUSCLE-TISSUE BY LIQUID-CHROMATOGRAPHY

A liquid chromatographic (LC) method was developed for the simultaneou s determination of nitrofurazone (NFZ), nitrofurantoin (NFT), and fura zolidone (FZD) in catfish muscle tissue. The drugs were extracted from the tissue with acetonitrile, and the lipids were removed from the ex tract with hexane. The acetonitrile extract was evaporated by rotary e vaporation, and the resultant drug residues were dissolved with LC mob ile phase. The mixture was sonicated, centrifuged, and filtered. The d rugs were determined by using LC with a C-18 reversed-phase (ODS Hyper sil) column, a mobile phase of acetonitrile-1% aqueous acetic acid (25 + 75), and a photodiode array ultraviolet detector at 375 nm. NFZ, NF T, and FZD were each determined in catfish tissue at 5 fortification l evels (80, 40, 20, 10, and 5 ng drug/g tissue). Average recoveries of each of the 3 drugs at each level ranged from 70.7 to 101.5%, and rela tive standard deviations ranged from 2.2 to 18.6%. The limit of detect ion of each drug was approximately 1 ng drug/g tissue, and the limit o f quantitation was 5 ng drug/g tissue. In the second part of the study , the method was used to determine nitrofuran residues incurred in cat fish tissue. Live channel catfish were intravascularly dosed (10 mg/kg body wt) with NFZ to generate drug-incurred fish muscle tissue. Incur red NFZ levels exceeded 400 ng drug/g tissue at 2 h after dosing but d ecreased rapidly to approximately 1 ng drug/g tissue by 8 h after dosi ng, as determined by this method.