
Keywords: E1, estrone; E2, 17β-estradiol; EE2, 17α-ethinylestradiol; E3, estriol; GC, gas chromatography; HLB, hydrophilic–lipophilic balance; HPLC, high performance liquid chromatography; HRMS, high-resolution mass spectrometry; HSS, high strength silica; LC, liqu