Table 2.

Urinary steroids measured by LCMS^a

Analyte	εb	Protonated mass (m/z)c	Linear range (ng/mL)	Sloped	r2e
E1	2138	504.22031	0.025–100	2.26 × 10−4	0.999
E2	2344	506.23596	0.025–100	1.14 × 10−4	0.998
E3, 16epi-E3, 17epi-E3	2188	522.23087	0.05–100	7.70 × 10−5	0.999
16α-OHE1	2138	520.21522	0.05–100	9.84 × 10−5	0.999
16-ketoE2	2344	520.21522	0.05–100	7.29 × 10−5	0.999
2-OHE1	2138	753.26628	0.05–50	3.52 × 10−4	0.999
2-OHE2	2344	755.28193	0.05–50	3.40 × 10−4	0.999
2-MeOE1	2138	534.23087	0.05–50	5.94 × 10−5	0.999
2-MeOE2	2344	536.24652	0.05–50	2.71 × 10−5	0.998
2-OH-3-MeE1	2138	534. 23087	0.05–50	5.90 × 10−5	0.998
4-OHE1	2138	753.26628	0.05–50	3.64 × 10−4	0.999
4-OHE2	2344	755.28193	0.05–50	7.18 × 10−4	0.998
4-MeOE1	2138	534. 23087	0.05–50	6.40 × 10−5	0.998
4-MeOE2	2344	536.24652	0.05–50	3.37 × 10−5	0.998
P	16982	315.23186	0.05–100	9.28 × 10−5	0.998
F	15500	363.21660	1–1,000	2.93 × 10−3	0.998
E	15136	361.20095	1–1,000	1.97 × 10−3	0.996
Internal Standards
E1-d4	2138	508.24542
E2-d3	2344	509.25479
2-MeOE2-d5	2344	541.27791
4-OHE2-d5	2344	760.31331
16α-OHE1-d5	2138	525.24661

^ausing orbitrap MS (model Exactive, Thermo Scientific) that allowed exact mass measurements

^bmolar extinction coefficient in methanol at 280 nm except for F (241 nm), E (238 nm), P (249 nm) used from CRC Handbook of Chemistry and Physics, 52nd ed. 1971; ε-values of E₁ metabolites, E₂ metabolites, and E₃ metabolites were deduced from E₁, E₂, and E₃, respectively

^ctheoretical (monoisotopic) exact mass of each protonated analyte used to monitor in positive mode in a +/− 5 ppm range to account for mass spectrometric inaccuracies; all analytes dansylated except for P, F, E

^dslope of linear regression after forcing curve through zero (no intercept); relative standard error<6%

^er² = coefficient of determination for linear regression