Fig. 1

Typical selected reaction monitoring chromatogram of 10 ng/mL 25(OH)D3, 10 ng/mL 3-epi-25(OH)D3 (a), 10 ng/mL 25(OH)D2 and 10 ng/mL 3-epi-25(OH)D2 (b) in serum
Typical selected reaction monitoring chromatogram of 10 ng/mL 25(OH)D3, 10 ng/mL 3-epi-25(OH)D3 (a), 10 ng/mL 25(OH)D2 and 10 ng/mL 3-epi-25(OH)D2 (b) in serum