Table III.
Short-term (24 h at 23°C), long-term (2 years at −70°C), and thaw and re-freeze (T/RF) stability of unprocessed samples; and stability of processed samples at 10°C (72 h) and −20°C (13 weeks).
| Analyte | Nominal concentration (ng/L) |
Measured concentration (ng/L) |
||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Unprocessed samples at −70°C for 2 year (%−diff) |
Unprocessed samples at 23°C for 24 h (%−diff) |
T/RF stability of unprocessed samples |
−20°C storage stability of processed samples |
10°C storage stability of processed samples |
||||||||
| Control | Five T/RF cycles (%–diff) |
Day 1 | Week 1 (%–diff) | Week 13 (%–diff) | Day 1 | Autosampler for 24 h (%–diff) |
Autosampler for 72 h (%–diff) |
|||||
| OTOL | 150.7 | 168.9 (12.10) | 218.0 | 198.2 (−9.09) | 57.0 | 60.7 (6.55) | 53.2 (−6.72) | 623.0 | 588.5 (−5.53) | 562.8 (−9.66) | ||
| 485.9 | 493.0 (1.48) | 511.3 (5.24) | 67.6 | 59.7 (−11.61) | 63.6 (−5.86) | |||||||
| 82.2 | 87.4 (6.38) | 92.3 (12.25) | ||||||||||
| 168.0 | 168.7 (0.40) | 181.1 (7.79) | ||||||||||
| 490.2 | 498.9 (1.75) | 501.3 (2.26) | ||||||||||
| 26DM | 121.3 | 109.8 (−9.46) | 157.5 | 148.9 (−5.46) | 19.8 | 17.8 (−10.28) | 17.6 (−10.92) | 459.6 | 426.9 (−7.11) | 418.3 (−8.98) | ||
| 502.6 | 492.6 (−2.01) | 519.1 (3.27) | 43.8 | 43.0 (−1.95) | 38.0 (−13.38) | |||||||
| 68.1 | 61.4 (−9.89) | 59.6 (−12.45) | ||||||||||
| 149.6 | 147.3 (−1.57) | 150.6 (0.63) | ||||||||||
| 543.4 | 480.5 (−11.58) | 499.1 (−8.16) | ||||||||||
| OANS | 153.4 | 148.0 (−3.48) | 158.2 | 144.4 (−8.71) | 44.9 | 46.4 (3.25) | 54.0 (20.39) | 427.1 | 420.2 (−1.60) | 405.1 (−5.15) | ||
| 505.8 | 498.5 (−1.44) | 488.8 (−3.37) | 70.5 | 66.4 (−5.88) | 64.1 (−9.05) | |||||||
| 92.8 | 83.0 (−10.51) | 86.4 (−6.87) | ||||||||||
| 153.5 | 137.6 (−10.39) | 141.5 (−7.81) | ||||||||||
| 544.4 | 531.9 (−2.28) | 516.4 (−5.14) | ||||||||||
| 1AMN | 110.8 | 120.0 (8.31) | 109.5 | 91.5 (−16.39) | 13.6 | 15.5 (14.37) | 14.1 (3.62) | 269.2 | 287.7 (6.87) | 303.4 (12.71) | ||
| 458.1 | 496.4 (8.36) | 434.9 (−5.08) | 34.1 | 33.7 (−1.30) | 31.8 (−6.84) | |||||||
| 43.8 | 53.1 (21.19) | 50.7 (15.84) | ||||||||||
| 94.1 | 115.7 (22.87) | 114.2 (21.25) | ||||||||||
| 449.4 | 472.3 (5.08) | 501.7 (11.64) | ||||||||||
| 2AMN | 111.7 | 116.7 (4.45) | 101.4 | 90.3 (−10.93) | 14.3 | 15.1 (5.54) | 15.2 (6.70) | 318.8 | 321.3 (0.81) | 323.7 (1.54) | ||
| 479.8 | 511.5 (6.62) | 476.7 (−0.63) | 35.4 | 38.1 (7.76) | 37.7 (6.46) | |||||||
| 53.4 | 56.8 (6.35) | 56.7 (6.27) | ||||||||||
| 96.1 | 100.7 (4.72) | 99.4 (3.42) | ||||||||||
| 528.8 | 513.3 (−2.93) | 509.1 (−3.71) | ||||||||||
| 4ABP | 109.0 | 111.9 (2.64) | 111.6 | 105.2 (−5.75) | 21.5 | 20.3 (−5.36) | 21.5 (0.00) | 347.0 | 339.9 (−2.06) | 342.0 (−1.46) | ||
| 446.1 | 467.5 (4.80) | 428.2 (−3.99) | 42.5 | 41.3 (−2.65) | 42.1 (−0.90) | |||||||
| 62.4 | 58.4 (−6.43) | 61.1 (−2.17) | ||||||||||
| 120.2 | 106.0 (−11.81) | 108.1 (−10.04) | ||||||||||
| 476.0 | 461.0 (−3.15) | 476.0 (0.00) | ||||||||||