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.

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.

LuHNInc, C, W., aNn P. D. H.qnulN. 1971. Sampling of fish muscle for M.S. 222 and quinaldine residues. J. Fish. Res. Bd, Canada 28: 113-115.Large variations in concentrations of M.S. 222 (tricaine methanesulfonate) and quinaldine (2-methylquinoline) residues occurred in various areas of fish fillets. Residue analyses of replicate samples from homogenized fillets yielded more representative results than samples cut from various areas of fillets.

In this gas-liquid chromatographic procedure for determining residues of methanesulfonate of m-aminobenzoic acid ethyl ester (MS-222) in fish muscle, homogenized tissue is extracted with distilled water, and proteins are removed by coagulation with trichloroacetic acid, centrifugation, and filtration. After careful pH adjustment of the filtrate, MS-222 is partitioned into benzene-ethyl ether and measured by alkali flame ionization gas chromatography. Tissues with known additions of 1–19 μg MS-222/ g were analyzed, with recoveries of 84–95%.