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. Author manuscript; available in PMC: 2021 Nov 1.
Published in final edited form as: Contraception. 2020 Aug 21;102(5):361–367. doi: 10.1016/j.contraception.2020.08.006

Figure 2.

Figure 2.

Representative multiple reaction monitoring (MRM) chromatograms of unlabeled and stable isotope-labeled endogenous steroid hormones and Nestorone in a charcoal-stripped serum (CSS) blank and a subject sample. The chromatogram in the top panel is a representative CSS blank, demonstrating absence of appreciable endogenous steroids. The chromatogram in the bottom panel is a representative simultaneous analysis of E2 (180 pg/mL), E1 (102 pg/mL), NES (178 pg/mL), and P4 (45 pg/mL) in a subject sample. E2, estradiol; E2, estrone; NES, Nestorone; P4, progesterone; d, deuterium; CPS, counts per second; min, minutes; CSS, charcoal-stripped serum.