This paper studies the effect of styrene divinyl benzene (SDB) solid phase extraction (SPE) and graphitized carbon black (GCB) SPE on the quantification of estradiol (E2) and ethinyl estradiol (EE2) by enzymelinked immunosorbent assay (ELISA) kit. The recovery rates of E2 and EE2 in spiked raw sewage samples drop from 181.4% and 122.6% to 113.3% and 109.4% respectively with the relative standard deviations dropped to below 10.0%. The reovery rate of E2 in final effluent decreases from 144.2% to 93.5% whilst the rate of EE2 has marginal variation, and the relative standard deviation drops from approximately 10.0% to lower than 8.0%. The estrogen levels measured by ELISA are collated with those measured by parellel liquid chromatrography coupled with time of flight mass spectrometry (HPLCMS(TOF)). GCB SPE with step elution is able to separate E2 and EE2 from the matrices thus reduces the cross reaction rate. GCB SPE decreases 38% and 15% false positives for E2 and EE2 ELISA analysis compared with SDB SPE. ELISA quantification with this improved GCB SPE pretreatment has the advantages of low cost and timesaving over the chemical analysis.