Table 3.
Results of the stability testing for α- and γ-amanitin, and internal standard (IS). Spiked blank urine samples stored under different conditions and extracts stored in the autosampler (n = 3, 10 ng/mL), peak area deviations of measurement at timepoint t0 compared to t1, % and CVs, %. CV, coefficient of variation; n.d., not determined.
| Analyte | Validation sample, (CV, %) | |||||
|---|---|---|---|---|---|---|
| Short term (24 h, 4 °C) | Benchtop (24 h, 22 °C) | Long term (4 weeks, 20 °C) | Freeze/thaw (24 h, − 20 °C) | Autosampler (1 day, 20 °C) |
Autosampler (4 days, 20 °C) |
|
| α-Amanitin | 100 (8.9) | 93 (13) | 110 (3.8) | 110 (7.7) | 94 (2.5) | 86 (2.6) |
| γ-Amanitin | 101 (6.0) | 93 (15) | 110 (5.0) | 109 (8.6) | 94 (2.1) | 86 (1.6) |
| Methyl-γ-amanitin (IS) | n.d | n.d | n.d | n.d | 95 (1.3) | 88 (1.7) |