Table 2c.
Diluted standards prepared by one investigator were frozen at −20°C and −80°C, then thawed and refrozen every 7 days up to three times. Standards frozen at −20°C and −80°C were assayed on the same day. All assays were done in triplicate. Eight absorbance values (0.1 – 0.8) were used as hypothetical samples and protein concentrations were calculated using each of the thawed standards.
| Hypothetical Sample (A565) | Calculated protein concentration (µg/ml) | |||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| −20°C Standards | −80°C Standards | |||||||||||
| 1 Thaw | 2 Thaws | 3 Thaws | Ave | St Dev | CV | 1 Thaw | 2 Thaws | 3 Thaws | Ave | St Dev | CV | |
| 0.10 | 8.41 | 5.68 | 9.71 | 7.93 | 2.05 | 0.26 | 13.77 | 14.81 | 19.75 | 16.11 | 3.20 | 0.20 |
| 0.20 | 84.38 | 88.45 | 88.13 | 86.99 | 2.26 | 0.03 | 70.67 | 77.77 | 81.20 | 76.55 | 5.37 | 0.07 |
| 0.30 | 156.90 | 162.87 | 162.10 | 160.62 | 3.25 | 0.02 | 129.58 | 143.07 | 146.21 | 139.62 | 8.84 | 0.06 |
| 0.40 | 226.39 | 231.06 | 232.29 | 229.91 | 3.11 | 0.01 | 190.71 | 211.00 | 215.47 | 205.73 | 13.20 | 0.06 |
| 0.50 | 293.20 | 294.36 | 299.22 | 295.59 | 3.19 | 0.01 | 254.35 | 281.89 | 289.96 | 275.40 | 18.67 | 0.07 |
| 0.60 | 357.63 | 353.69 | 363.32 | 358.21 | 4.84 | 0.01 | 320.83 | 356.19 | 371.05 | 349.36 | 25.80 | 0.07 |
| 0.70 | 419.91 | 409.72 | 424.91 | 418.18 | 7.74 | 0.02 | 390.57 | 434.42 | 460.92 | 428.64 | 35.53 | 0.08 |
| 0.80 | 480.24 | 462.94 | 484.27 | 475.82 | 11.33 | 0.02 | 464.10 | 517.30 | 563.22 | 514.87 | 49.61 | 0.10 |