Bench top (25°C) and freeze thaw (−80°C) for stability four cycle quality control (QC, n = 6) standards of methamphetamine; 4-hydroxymethamphetamine; Amphetamine; 4-hydroxyamphetamine and norephedrine in plasma
All CC and QC standard values were presented in one decimal place except CC-8 and 9, and LQC and LLOQ which were presented in two decimal places.
| Name | Nominal concentration. (ng/ml) | Bench Top (25°C) | Freeze Thaw (−80°C) | ||
|---|---|---|---|---|---|
| HQC | LQC | HQC | LQC | ||
| 640.0 | 14.94 | 640.0 | 14.94 | ||
| MA | Actual (ng/ml) | 661.8 | 15.3 | 592.4 | 14.7 |
| % Accuracy | 103.5 | 102.4 | 92.0 | 98.6 | |
| % CV | 7.8 | 10.1 | 11.7 | 14.8 | |
| 4-OH MA | Actual (ng/ml) | 695.8 | 14.15 | 655.1 | 14.7 |
| % Accuracy | 108.7 | 94.6 | 102.3 | 98.7 | |
| % CV | 10.8 | 16.3 | 17.5 | 14.6 | |
| AM | Actual (ng/ml) | 645.8 | 15.3 | 586.1 | 14.8 |
| % Accuracy | 101.0 | 102.5 | 91.6 | 99.2 | |
| % CV | 7.1 | 8.7 | 10.2 | 12.8 | |
| 4-OH AM | Actual (ng/ml) | 623.3 | 15.7 | 612.1 | 16.9 |
| % Accuracy | 97.4 | 105.0 | 95.7 | 113.0 | |
| % CV | 9.0 | 10.8 | 13.0 | 7.8 | |
| Norephedrine | Actual (ng/ml) | 629.7 | 14.8 | 558.9 | 15.4 |
| % Accuracy | 98.5 | 99.3 | 87.4 | 102.7 | |
| % CV | 7.6 | 9.2 | 11.2 | 7.2 | |
CV (precision), coefficient of variation, HQC, high QC; LQC, lower QC; MQC, middle QC.