Table 8.
Stability study of MX under various test conditions
| Condition | T (°C) | Samplea | Period | Recovery ± SD (%) (n = 6) |
|---|---|---|---|---|
| Refrigerator | 4 | Stock solution | 5 months | 96.4 ± 7 |
| Bench-top | 23 | Stock solution | 18 hours | 98.4 ± 6 |
| Bench-top | 23 | Low QC | 18 hours | 89.4 ± 4 |
| Mid QC | 18 hours | 94.5 ± 4 | ||
| High QC | 18 hours | 95.7 ± 2 | ||
| Autosampler | 15 | Low QC | 3 days | 90.7 ±6 |
| Mid QC | 3 days | 94.5 ± 5 | ||
| High QC | 3 days | 96.9 ±3 | ||
| Freeze & thaw | −70 to 23 | Low QC | 3 cycles | 96.6 ± 2 |
| Mid QC | 3 cycles | 94.4 ± 2 | ||
| High QC | 3 cycles | 96.2 ± 2 | ||
| Deep freezer (Long-term) | −70 | Low QC | 5 months | 95.7 ±3 |
| Mid QC | 5 months | 101 ± 2 | ||
| High QC | 5 months | 103 ± 2 |
a
The concentration of MX stock solution was 2.00 mg/ml which was measured by serial dilution to 45.0 ng/ml in 1% formic acid. The concentration of MX in LQC, MQC and HQC were 3.50, 45.0 and 450 ng/ml, respectively.