A sensitive spectrophotometric determination of atrazine in micellar medium and its application in environmental samples

A sensitive analytical procedure based on solid phase extractive-spectrophotometry has been established for the determination of the widely used herbicide atrazine .The method is based on the Konig reaction in which atrazine reacts with pyridine reagent to form a quaternary pyridinium halide, which further forms glutaconic aldehyde in the presence of alkali. Glutaconic aldehyde is subsequently coupled with 4-aminoacetanilide in the micellar medium of anionic surfactant sodium dodecyl sulphate to give a yellow-orange dye. The produced dye was enriched on a C-18 cartridge and is measured spectrophotometrically at 460 nm. The sensitivity and selectivity of the method was largely enhanced in the micellar media and SPE on the C-18 cartridge and avoids the use of toxic solvents. Beer's law was obeyed in the range 0.012-0.12 mu g mL(-1). Molar absorptivity and Sandell's sensitivity were found to be 1.52 x 10(6) L mol(- 1) cm(-1) and 0.0002 mu g cm(-2), respectively. The limit of detection and quantification were 0.001 and 0.003 mu g mL(-1), respectively. The proposed method was applied successfully for the determination of atrazine in environmental and biological samples with a recovery range of 96-101 %. The method was found to be free from interference of a large number of foreign species. The accuracy and reliability of the method was further established by parallel determination by the reference method, and by recovery studies.