C3-Epimer of 25-Hydroxyvitamin D3 as a Superior Marker for Predicting the Severity of Chronic Kidney Disease in Rheumatoid Arthritis Patients

Figure 1

Different retention times of 25(OH)D3 and C3-epi-25(OH)D3. Note: 25(OH)D3 and C3-epi-25(OH)D3 have identical monoisotopic masses and fragmentation patterns () but were separated according to different retention times (; ).