Abstract
Three sensitive spectrophotometric methods were developed for the determination of cypermethrin in insecticidal formulations and environmental samples. The methods were based on the hydrolysis of cypermethrin with ethanolic KOH to form 3-phenoxy benzaldehyde. The resultant aldehyde group was condensed with 4-aminobenzoic acid in acidic medium to form red color product having lambda(max) of 500 nm (Method A), condensed with anthranilic acid in presence of basic medium to form orange red color product having lambda(max) of 482 nm (method B) or condensed with 4-chlorophenyl hydrazine to form purple color product having lambda(max) of 550 nm (method C). The color derivatives were stable for 7, 8 and 10 days for methods A, B and C, respectively. The Beer's law was obeyed over the concentration range of 40-1200, 50-1500 and 50-2000 ng mL(-1) for methods A, B and C, respectively. The molar absorptivity and Sandell's sensitivity, detection and quantification limits were calculated. The proposed methods have been applied for the analysis of cypermethrin in its formulations, water (tap and river), grain (rice and wheat), vegetables and fruits samples.