Table 3.
Inter-day precision (n) of vitamin D metabolites in plasma, breastmilk, and infant formula samples measured by (a) Waters Quattro PremierTM/XE and (b) Agilent 6495B.
| Analyte | |||
|---|---|---|---|
| a. Waters Quattro PremierTM/XE | |||
| Plasma (n = 10) | 25(OH)D2 | 25(OH)D3 | 3-Epi25(OH)D3 |
| Medium1 | |||
| Average (nmol/L) | - | 55.5 ± 5.2 | - |
| RSD (%) | 9 | ||
| b. Agilent 6495B | |||
| Plasma (n = 10) | 25(OH)D2 | 25(OH)D3 | 3-Epi25(OH)D3 |
| Low2 | |||
| Average (nmol/L) | 30.2 ± 2.7 | 42.9 ± 3.4 | 34.5 ± 2.2 |
| RSD (%) | 9 | 8 | 6 |
| Medium2 | |||
| Average (nmol/L) | 71.2 ± 4.2 | 102.6 ± 5.6 | 48.2 ± 3.6 |
| RSD (%) | 6 | 5 | 7 |
| High2 | |||
| Average (nmol/L) | 115.3 ± 8.9 | 162.7 ± 9.0 | 99.9 ± 5.6 |
| RSD (%) | 8 | 6 | 6 |
| Breastmilk (n = 10) | 25(OH)D2 | 25(OH)D3 | 3-Epi25(OH)D3 |
| Low3 | |||
| Average (nmol/L) | <7 | 12.0 ± 2 | 5.8 ± 1.7 |
| RSD (%) | 17 | 30 | |
| Medium3 | |||
| Average (nmol/L) | 39.9 ± 2.7 | 65.0 ± 5.2 | 45.7 ± 2.6 |
| RSD (%) | 7 | 8 | 6 |
| High3 | |||
| Average (nmol/L) | 97.9 ± 4.6 | 114.8 ± 8 | 92.0 ± 9 |
| RSD (%) | 5 | 7 | 10 |
| Infant formula (n = 10) | 25(OH)D2 | 25(OH)D3 | 3-Epi25(OH)D3 |
| Low4 | |||
| Average (nmol/L) | <7 | <4.3 | <1.7 |
| SD | |||
| RSD (%) | |||
| Medium4 | |||
| Average (nmol/L) | 21.4 ± 2.3 | 66.6 ± 2.7 | 32.2 ± 1.8 |
| RSD (%) | 11 | 4 | 6 |
| High4 | |||
| Average (nmol/L) | 93.2 ± 8.7 | 112.1 ± 4.1 | 107.1 ± 3.6 |
| RSD (%) | 9 | 4 | 3 |