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| Optimization of solidphase extraction conditions using response surface methodology to determine 17βestradiol in sewage |
| 1.Key Laboratory of Environmental Medicine Engineering of Ministry of Education, Southeast University, Nanjing, Jiangsu 210009, China; 2.School of Civil Engineering, Southeast University, Nanjing, Jiangsu 210096, China) |
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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.
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2012, Vol. 33 
