IC Determination of Residual Amount of 4-Chlorophenoxyacetic Acid in Cowpea and Bitter Gourd

IC was applied to the determination of residual amount of 4-chlorophenoxyacetic acid in cowpea and bitter gourd. The sample of cowpea and bitter gourd was extracted ultrasonically with mixture of 1.8 mmol·L^-1 Na₂CO₃ and 1.7 mmol·L^-1 NaHCO₃ solution, and then purified with SPE C₁₈ colunm. Mixture of 1.8 mmol·L^-1 Na₂CO₃ and 1.7 mmol·L^-1 NaHCO₃ solution was used as mobile phase,and UV detector was used in determination. Linear relationship between values of peak area and mass concentration of 4-chlorophenoxyacetic acid was kept in the range of 0.05-25.0 mg·L^-1, with detection limits (3S/N) in cowpea and bitter gourd of 0.04, 0.03 mg·kg^-1 respectively. On the base of blank sample, test for recovery was made by standard addition method; values of recovery found were in the range of 96.7%-109%, with RSD's (n=5) in the range of 4.7%-7.7%.