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Department of Chemistry, Govt. P.G. College, Solan-173 212, Himachal Pradesh, India E-mail : rajumeena4@yahoo.in Department of Chemistry, Govt. College, Amb (Una), Himachal Pradesh, India Department of Chemistry, Himachal Pradesh University, Shimla-171 005, Himachal Pradesh, India Manuscript received online 22 December 2013, revised 26 May 2014, accepted 31 May 2014 An extractive spectrophotometric method for benomyl adsorption in soils has been developed. The method is based on the microwave assisted alkaline hydrolysis of the fungicide to carbendazim and n-butylamine and the colour reaction of the latter with carbon disulphide and copper(I) perchlorate to form chloroform extractable brownish yellow copper(I) n-butyldithiocarbamate showing maximum absorbance at 360 nm. The colour is stable for at least 2 h and the fungicide concentration can be determined with a maximum relative standard deviation of 1.0%. The adsorption isotherms of benomyl on four soils of different characteristics have been evaluated by Freundlich’s adsorption equation followed by evaluation of its leaching potential in terms of ground water ubiquity score (GUS). The GUS has been found in the range 0.3–0.4, classifying it as a nonleacher pesticide. |
