Rupp H S, Munns R K, Long A R
U.S. Food and Drug Administration, Animal Drugs Research Center, Denver Federal Center, CO 80225-0087.
J AOAC Int. 1993 Nov-Dec;76(6):1235-9.
A liquid chromatographic (LC) method was developed for the simultaneous determination of nitrofurazone (NFZ) and furazolidone (FZD) in shrimp muscle tissue. The drugs are extracted from the tissue with acetonitrile, and the lipids and lipophilic pigments are removed from the extract with hexane. The remaining acetonitrile extract is evaporated by rotary evaporation, and the resultant residues are dissolved with LC-grade water, applied to a preconditioned C18 solid-phase extraction column, and eluted with acetonitrile. The acetonitrile eluant is then dried under nitrogen, and the resultant drug residues are dissolved with mobile phase and filtered. The drugs are determined by LC by using a C18 reversed-phase (octyldecylsilyl Hypersil) column, a mobile phase of acetonitrile--1% aqueous acetic acid (25 + 75, v/v), and a photodiode array UV detector at 375 nm. NFZ and FZD were determined in shrimp tissue at each of 5 spiking levels (64, 32, 16, 8, and 4 ng drug/g tissue). Absolute recoveries ranged from 70.6 to 78.4%, and relative standard deviations ranged from 4.0 to 13.6%. The limit of detection of pure standard of each drug was approximately the equivalent of 1 ng drug/g tissue, and the limit of determination in a sample was 4 ng drug/g tissue.
