ABSTRACT
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 degrees 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.
Subject(s)
Fishes/metabolism , Invertebrates/analysis , Niclosamide/analogs & derivatives , Pesticide Residues/analysis , Soil Pollutants/analysis , Water Pollutants, Chemical/analysis , Water Pollutants/analysis , Animals , Chromatography, Gas , Ethanolamines/analysis , Niclosamide/analysis , SolventsABSTRACT
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 microgram MS-222/g were analyzed, with recoveries of 84-95%.
