Preparation of reagents for the sensitive spectrophotometric determination of carbaryl in environmental samples

A simple and sensitive spectrophotometric method was described for the determination of carbaryl in its formulations, fortified water, food grains, polluted water, plant material (cabbage), soil, and biological samples (blood and urine) with the prepared coupling reagents. The method was based on alkaline hydrolysis of the carbaryl pesticide, and the resultant hydrolysis product of 1-naphthol was coupled with 2,6-dibromo-4-methylaniline to give a purple product with lambda(max) of 505nm or coupling with 2,4,6-tribromoaniline to produce a violet colored product with lambda(max) 535 nm or coupling with 2,6-dibromo-4-nitroaniline to form pale-red colored product has a lambda(max) of 492 nm. The formation of colored derivatives with the coupling agents are instantaneous and stable for 48h, 40h, and 36h, respectively. The results indicate the proposed method's sensitivity, selectivity, and the recovery of the carbaryl from the fortified water, food grains, polluted water, plant material (cabbage), soil, and biological samples (blood and urine) are higher than the other methods.