Abstract:Response surface methodology (RSM) was used to optimize the solid phase extraction (SPE) process for determining 17β-estradiol (E2) in sewage. A quadratic equation between the extraction recovery rate and main effect factors was established. The results indicate that the sequence of three main influence factors on recovery is elution volume> sample rate>elution rate. The optimal operating conditions of SPE are obtained with elution volume of 10.54 mL, sample rate of 10.25 mL·min-1 and elution rate of 4.06 mL·min-1. Under the optimal conditions, E2 recovery rates of actual sewage from three sewage treatment plants (STPs) located in Jiangsu are ranged from 67.2%to 83.4%. E2 concentrations in the influent of STPs are the range of 21.6 to 78.0 ng·L-1. The three STPs all have some effect on the E2 removal with average removal rates of 68.33% for SBR process, 59.34% for oxidation ditch process and 64.18% for A2/O process. The final effluent concentrations of E2 in the three STPs still reach the range of 8.4 to 22.1 ng·L-1, which are several times higher than that of predicted noneffect concentration.