Table 4.
Stability testing of thymidine and 2’-deoxyuridine in urine.
| Stability Test | Thymidine | 2’-Deoxyuridine | ||||||
|---|---|---|---|---|---|---|---|---|
| Concentration (µg/mL) | CV% | Accuracy (%) | Concentration (µg/mL) | CV% | Accuracy (%) | |||
| Spiked | Mean ± SD | Spiked | Mean ± SD | |||||
| Short term | ||||||||
| Time 0 | 3.01 | 3.19 ± 0.03 | 0.89 | 105.99 | 3.01 | 3.01 ± 0.07 | 2.40 | 103.07 |
| 37.58 | 34.96 ± 0.51 | 1.47 | 93.03 | 37.61 | 38.97 ± 1.57 | 4.02 | 103.62 | |
| 24 h RT + PCA | 3.01 | 2.92 ± 0.05 | 1.66 | 97.05 | 3.01 | 3.10 ± 0.10 | 3.19 | 103.08 |
| 37.58 | 31.32 ± 0.54 | 1.73 | 83.34 | 37.61 | 36.98 ± 0.95 | 2.57 | 98.33 | |
| 24 h RT | 3.01 | ND | 3.01 | ND | ||||
| 37.58 | ND | 37.61 | ND | |||||
| 14 days 4 °C + PCA | 3.01 | 3.03 ± 0.17 | 5.71 | 100.75 | 3.01 | 2.69 ± 0.16 | 5.96 | 89.26 |
| 37.58 | 30.15 ± 0.63 | 2.07 | 80.24 | 37.61 | 33.42 ± 1.13 | 3.38 | 88.87 | |
| 14 days 4 °C | 3.01 | ND | 3.01 | ND | ||||
| 37.58 | ND | 37.61 | ND | |||||
| Freeze-thaw | ||||||||
| Cycle 1 + PCA | 3.01 | 3.18 ± 0.09 | 2.85 | 105.68 | 3.01 | 3.07 ± 0.07 | 2.26 | 102.08 |
| 37.58 | 34.74 ± 0.44 | 1.27 | 92.44 | 37.61 | 38.43 ± 0.82 | 2.15 | 102.19 | |
| Cycle 2 + PCA | 3.01 | 3.24 ± 0.10 | 3.24 | 107.57 | 3.01 | 3.23 ± 0.13 | 4.02 | 107.31 |
| 37.58 | 35.76 ± 0.63 | 1.77 | 95.17 | 37.61 | 39.56 ± 0.67 | 1.69 | 105.17 | |
| Cycle 3 + PCA | 3.01 | 3.24 ± 0.05 | 1.43 | 107.70 | 3.01 | 3.01 ± 0.10 | 3.43 | 100.08 |
| 37.58 | 35.66 ± 0.71 | 1.99 | 94.88 | 37.61 | 37.82 ± 0.82 | 2.16 | 100.55 | |
| Cycle 1 | 3.01 | 2.82 ± 0.06 | 2.10 | 93.82 | 3.01 | 2.46 ± 0.05 | 1.87 | 81.84 |
| 37.58 | 33.56 ± 0.53 | 1.58 | 89.29 | 37.61 | 35.09 ± 0.50 | 1.42 | 93.31 | |
| Cycle 2 | 3.01 | 2.80 ± 0.08 | 2.72 | 92.90 | 3.01 | 2.43 ± 0.05 | 1.98 | 80.76 |
| 37.58 | 33.39 ± 0.80 | 2.40 | 88.85 | 37.61 | 34.73 ± 0.72 | 2.07 | 92.34 | |
| Cycle 3 | 3.01 | 2.83 ± 0.06 | 2.02 | 93.89 | 3.01 | 2.37 ± 0.06 | 2.73 | 78.73 |
| 37.58 | 33.91 ± 0.81 | 2.38 | 90.23 | 37.61 | 33.35 ± 0.66 | 1.97 | 88.67 | |
| Autosampler | ||||||||
| Time 0 | 1.00 | 1.19 ± 0.01 | 0.84 | 118.50 | 1.00 | 1.18 ± 0.02 | 1.77 | 117.50 |
| 3.01 | 3.39 ± 0.03 | 0.85 | 112.49 | 3.01 | 3.32 ± 0.06 | 1.89 | 110.17 | |
| 15.03 | 16.23 ± 0.24 | 1.45 | 108.00 | 15.05 | 116.44 ± 0.36 | 2.20 | 109.20 | |
| 37.58 | 38.71 ± 0.81 | 2.08 | 103.00 | 37.61 | 40.30 ± 0.71 | 1.75 | 107.14 | |
| 24 h 4 °C | 1.00 | 1.14 ± 0.05 | 3.97 | 113.50 | 1.00 | 1.13 ± 0.07 | 5.84 | 113.43 |
| 3.01 | 3.28 ± 0.02 | 0.61 | 108.97 | 3.01 | 3.26 ± 0.15 | 4.52 | 108.45 | |
| 15.03 | 16.04 ± 0.30 | 1.90 | 106.72 | 15.05 | 15.92 ± 0.33 | 2.10 | 105.75 | |
| 37.58 | 37.83 ± 0.77 | 2.04 | 100.67 | 37.61 | 38.11 ± 0.50 | 1.32 | 101.33 | |
| 48 h 4 °C | 1.00 | 1.14 ± 0.04 | 3.52 | 114.30 | 1.00 | 1.09 ± 0.10 | 8.72 | 109.38 |
| 3.01 | 3.32 ± 0.08 | 2.37 | 110.43 | 3.01 | 3.17 ± 0.12 | 3.70 | 105.26 | |
| 15.03 | 16.60 ± 0.34 | 2.06 | 110.47 | 15.05 | 15.21 ± 0.32 | 2.14 | 101.06 | |
| 37.58 | 38.38 ± 1.23 | 3.21 | 102.12 | 37.61 | 38.57 ± 1.04 | 2.69 | 102.56 | |
| 72 h 4 °C | 1.00 | 1.14 ± 0.02 | 1.93 | 114.12 | 1.00 | 1.18 ± 0.01 | 1.19 | 118.10 |
| 3.01 | 3.32 ± 0.04 | 1.21 | 110.33 | 3.01 | 3.32 ± 0.02 | 0.64 | 110.26 | |
| 15.03 | 16.27 ± 0.18 | 1.09 | 108.24 | 15.05 | 15.94 ± 0.31 | 1.98 | 105.88 | |
| 37.58 | 37.63 ± 1.13 | 2.99 | 100.13 | 37.61 | 39.38 ± 0.57 | 1.44 | 104.70 | |
ND = not detected; RT = room temperature; PCA = perchloric acid.