Research Article
Determination of Morphine and Codeine in Human Urine by Gas Chromatography-Mass Spectrometry
Table 2
Summary of stability of morphine and codeine under various storage conditions
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| Compound | Condition | Concentration (ng/mL) | RSD | RE | Added | (%) | (%) |
| Morphine | Three freeze–thaw cycles | 50 | 2.5 | −10.1 | 200 | 1.4 | −8.9 | 1600 | 4.3 | −12.5 | Autosampler ambient 12 h | 50 | 2.1 | −10.5 | 200 | 1.3 | −6.2 | 1600 | 3.5 | −9.2 |
| Codeine | Three freeze–thaw cycles | 50 | 3.2 | −8.9 | 200 | 3.3 | −11.2 | 1600 | 3.0 | −14.1 | Autosampler ambient 12 h | 50 | 3.3 | −11.1 | 200 | 3.2 | −12.9 | 1600 | 3.3 | −14.4 |
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