Table 2.
Intra-day (n) of vitamin D metabolites in plasma, breastmilk, and infant formula samples measured by (a) Waters Quattro PremierTM/XE and (b) Agilent 6495B.
| Intra-Day Precision | Vitamin D Metabolites | ||
|---|---|---|---|
| a. Waters Quattro PremierTM/XE | |||
| Plasma (n = 6) | 25(OH)D2 | 25(OH)D3 | 3-Epi25(OH)D3 |
| Medium1 | |||
| Average (nmol/L) | - | 55.7 ± 4.8 | - |
| RSD (%) | 8 | ||
| b. Agilent 6495B | |||
| Plasma (n = 10) | 25(OH)D2 | 25(OH)D3 | 3-Epi25(OH)D3 |
| Low2 | |||
| Average (nmol/L) | 31.5 ± 4.4 | 46.1 ± 2.8 | 34.6 ± 2.7 |
| RSD (%) | 14 | 6 | 8 |
| Medium2 | |||
| Average (nmol/L) | 76.2 ± 7.5 | 111.0 ± 3.9 | 49.3 ± 3.5 |
| RSD (%) | 10 | 3 | 7 |
| High2 | |||
| Average (nmol/L) | 120.3 ± 8.9 | 177.9 ± 14.6 | 105.6 ± 5.6 |
| RSD (%) | 7 | 8 | 5 |
| Breastmilk (n = 10) | 25(OH)D2 | 25(OH)D3 | 3-Epi25(OH)D3 |
| Low3 | |||
| Average (nmol/L) | <LOQ | 11.7 ± 1.9 | 6.8 ± 1.0 |
| RSD (%) | 16 | 14 | |
| Medium3 | |||
| Average (nmol/L) | 47.8 ± 3.0 | 71.6 ± 2.5 | 51.7 ± 2.3 |
| RSD (%) | 6 | 4 | 4 |
| High3 | |||
| Average (nmol/L) | 103.1 ± 4.4 | 126.8 ± 9.4 | 96.7 ± 4.6 |
| RSD (%) | 4 | 7 | 5 |
| Infant formula (n = 10) | 25(OH)D2 | 25(OH)D3 | 3-Epi25(OH)D3 |
| Low4 | |||
| Average (nmol/L) | <7.6 | <7.8 | <7.8 |
| RSD (%) | |||
| Medium4 | |||
| Average (nmol/L) | 18.1 ± 3.0 | 75.3 ± 6.6 | 31.1 ± 1.7 |
| RSD (%) | 17 | 9 | 5 |
| High4 | |||
| Average (nmol/L) | 88.5 ± 8.0 | 119.2 ± 6.1 | 109 ± 3.3 |
| RSD (%) | 9 | 5 | 3 |
Relative standard deviation (RSD %).