HPLC Determination the Residual Amounts of 6 Common Environmental Estrogens in Wastewater from Farms with Separation by Automatic Solid Phase Extraction

The wastewater sample (1 000 mL) was stood for about 1 h, and the supernatant (500 mL) was taken and filtered through 0.45 μm filter membrane. The filtrate was passed through solid phase extraction column at a flow rate of 10 mL·min^-1. The extraction column was eluted with CH₃OH-H₂O (80+20) mixture to desorb the 6 common environmental estrogens from the column, and the eluate was blown to near dryness with nitrogen. The residue was dissolved in 1.0 mL of methanol and the solution was filtered with 0.45 μm filter membrane. 6 common environmental estrogens in the filtrate were determined by high performance liquid chromatography with diode array detector at the wavelength of 225 nm. As shown by the results, linear relationships between values of response signals and mass concentration of the 6 common environmental estrogens were found in the range of 0.10-5.0 mg·L^-1, with detection limits (3S/N) in the range of 0.03-0.05 mg·L^-1. Test for recovery was made by standard addition method, giving results in the range of 90.7%-108%. Values of RSDs (n=6) found by repeatability test were in the range of 3.0%-4.8%.