Recoveries % Method 1 Method 2 Method 3 Method 4 Method 5
Estrone (E1) 25-35 100-120 60-70 40-50 120-140
RSD % 23.5 12.8 10.8 15.7 10.8
Estradiol (E2) 26.1-33 85-110 61-68 41.5-49.2 110-135
RSD % 16.5 18.1 7.6 17.0 14.3
Estriol (E3) 25.2-29 89.8-110 65-70 42-49 111-135
RSD % 9.9 14.2 5.2 10.8 13.7
17a-ethinylestradiol (EE2) 27-34.5 90-120 64.2-70 45-49 121-138
RSD % 17.2 18.2 6.1 6.0 9.28
Table 2: Recoveries of SPE procedure for target estrogens using standards with a concentration of 20.00 μg L-1 (n=3).