Abstract
Linuron and its known and/or suspected metabolites are extracted from crops with acetone. The acetone is evaporated, and the aqueous residue containing precipitated plant materials and linuron and metabolites is extracted several times with hexane to remove linuron and any 3,4-dichloroaniline, a metabolite. The 3,4-dichloroaniline is separated from the linuron by HC1 extraction. Other possible metabolites, 3-(3,4- dichlorophenyl)-l-methoxy urea, 3-(3,4-dichlorophenyl)- l-methyl urea, and 3-(3,4-dichlorophenyl) urea, remain in the aqueous phase which is made basic with ammonium hydroxide. These metabolites are extracted into hexane and identified by thin layer chromatography. Linuron and metabolites other than 3,4-dichloroaniline can be determined colorimetrically after acid hydrolysis to the aniline, followed by a diazotization reaction and coupling with iV-(l-naphthyl) ethylenediamine. Levels as low as 0.02 ppm linuron can be detected. Recoveries of 98.9% were found. Bound linuron can be determined by alkaline hydrolysis or by enzymatic digestion of crop material which frees the undegraded bound linuron
ISOLATION AND ANALYSIS OF STEROIDAL SAPONINS FROM POLYGONATUM ODORATUM (MILL.) DRUCE