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Largemouth bass (Micropterus salmoides) exposed to a 1.0-yitg/mL solution of the lampricide 3-trifluoromethyl-4-nitro[14C]phenol (TFM) for up to 24 h accumulated radioactive residues in all tissues analyzed at each of five successive sampling periods. Maximum concentrations occurred after 8 h in brain and muscle and after 12 h in blood, liver, kidney, and head plus viscera. Concentrations of radioactivity in the bile increased throughout the experiment. In a second group of fish exposed to 1.0 Mg/mL of [14C]TFM for 12 h and then transferred to lampricide-free flowing water, the concentration of radioactive materials in tissues generally decreased with time throughout a 72-h elimination period. No TFM was detected in muscle tissue 12 h after the fish were transferred to lampricide-free water. The presence of conjugated TFM in the bile was confirmed. Hexane/ether extracts contained [14C]TFM and other unidentified 14C materials from muscle and head plus viscera, whereas methanol extracts taken after the hexane/ether extraction contained only a negligible amount of [14C]TFM but large quantities of unidentified, polar 14C compounds.

1977. Mention of a trademark or proprietary product does not constitute a guarantee or warranty of the product by the U.S. Department of Agriculture or North Carolina State University, nor does it imply approval to exclusion of other products that may be suitable.

A gas-liquid chromatographic (GLC) method is described for determining residues of Bayer 73 (2-aminoethanol salt of 2’,5-dichloro-4’-nitrosalicylanilide) in fish muscle, aquatic invertebrates, mud, and water by analyzing for 2-chloro-4-nitroaniline (CNA), a hydrolysis product of Bayer 73. Bayer 73 residues are extracted from fish muscle tissue, invertebrates, and mud with acetone-formic acid (98+2), and partitioned from water samples with chloroform. After sample cleanup by solvent and acid-base partitioning, the concentrated extract is hydrolyzed with 2N NaOH and H2O2 for 10 min at 95°C. The CNA is then partitioned into hexane-ethyl ether (7+3) and determined by electron capture GLC. Average recoveries were 88% for fish, 82% for invertebrates, 82% for mud, and 98% for water at 3 or more fortification levels.