Kinetics Study of Carbaryl Degradation in Squash and Cucumber Fruits

In this study, residual levels of carbaryl insecticides were determined in squash (summer squash, ronde de nice) and cucumber (C. sativus) fruits using spectrophotometry. The degradation rate, degradation percentage, half-life and activation energy of carbaryl degradation were calculated. The degradation reaction of the carbaryl was found to follow first-order reaction kinetics. The half-lifetimes (t1/2) ranged between 2.18 and 2.32 days, and the activation energies (Ea) of carbaryl degradation for squash and cucumber samples were 10.34 kcal/mole and 8.95 kcal/ mole respectively. The degradation of carbaryl residue was greatly affected by small increases in temperature. Based on the maximum residue limit (MRL), the safety time was found to be five days after carbaryl application. The limit of detection (LOD) of the method used for carbaryl measurement in fruits in this study was 0.023 ppm, and the average recovery percentage of carbaryl was 95.98%.