Figure 5.

Chromatograms referring to the determination of (A) progesterone (P4) standard at 10 μg mL^–1, (B) spiked human plasma sample at 10 μg mL^–1 with P4 (green line) and blank pool human plasma sample (blue line), (C) 35 weeks pregnant woman plasma, and (D) 8 weeks pregnant woman plasma. Chromatographic conditions: Phenomenex Gemini C18 analytical column (250 mm × 4.6 mm, 5 μm) without temperature control, mobile phase composed of acetonitrile:ultrapure water (70:30, v/v), flow rate at 1.0 mL min^–1, 20 μL injection volume, and detection at λ = 235 nm.