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E-Journal of Chemistry
Volume 2 (2005), Issue 3, Pages 193-198

Extractive Spectrophotometric determination of Dimethoate in Environmental Samples with Azure-B

K. M. Reddy1 and P. Chiranjeevi2

1Department of Chemistry, S. V. Arts College, Tirupati – 517 502, India
2Environmental Monitoring Laboratories, Department of Chemistry, S.V.University, Tirupati – 517 502, India

Received 23 March 2005; Accepted 31 May 2005

Copyright © 2005 Hindawi Publishing Corporation. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


A new simple and selective spectrophotometric method is developed for the determination of dimethoate by using Azure-B is described. The method was based on the alkaline hydrolysis of dimethoate in presence of sodium ethoxide to form sodium dimethyl dithiophosphate (Na-DMDTP). The Na-DMDTP was formed as an ion-pair complex with cationic dye, azure-B. The ion-pair complex was extracted into chloroform. The color of the organic layer was measured at 535 nm. The method was applied to the determination of dimethoate residues in water, grain and soil samples.