HPLC Determination of R-fenoxaprop-p-ethyl with Eggshell Membrane Solid Phase Extraction

HPLC with eggshell membrane solid phase extraction was applied to the determination of the herbicide R-fenoxaprop-p-ethyl. The optimized conditions found were as follows: ① time of solid phase extraction was 80 min; ② amount of methanol used as eluent was 1 mL; ③ acidity of sample solution was pH 7; ④ volume of sample solution was 25 to 100 mL. C18 chromatographic column was used as stationary phase, and a mixture of methanol and water (80+20) was used as mobile phase. UV-detection at 236 nm was adopted in the determination. Linear relationship between values of peak area and mass concentration of R-fenoxaprop-p-ethyl was kept in the range of 5.00-50.0 μg·L-1, with detection limit (3S/N) of 1.2 μg·L-1. The proposed method was applied to the analysis of samples of water and wheat powder, giving values of recovery and RSD′s (n=5) in the ranges of 75.4%-95.2% and 3.7%-5.8% respectively.