Table 3.
Stability tests performed for the investigated drugs of abuse in wastewater samples.
| Compounds | Freeze-thaw stability | Short-term stability | Post-preparative stability | |||
|---|---|---|---|---|---|---|
| difference [%]a | SD [%] | difference [%] | SD [%] | difference [%] | SD [%] | |
| MDA | 0.9 | 0.3 | −0.3 | 2.4 | 2.2 | 2.2 |
| AMPH | 2.6 | 1.2 | −4.6 | 1.5 | 1.1 | 1.3 |
| MET | 3.8 | 1.1 | −6.0 | 1.5 | 2.2 | 2.5 |
| MDEA | 9.7 | 0.6 | 0.1 | 2.4 | 3.5 | 0.1 |
| MDMA | 8.0 | 2.0 | 4.3 | 0.7 | −0.5 | 0.5 |
| BEC | 2.8 | 0.8 | 0.2 | 0.1 | 2.2 | 1.6 |
| MEPH | 26.6 | 3.6 | 14.6 | 1.8 | −4.5 | 1.9 |
| KET | 18.9 | 2.1 | 11.9 | 1.1 | 1.6 | 0.8 |
| 6-AM | 6.8 | 3.2 | 1.8 | 4.9 | −5.0 | 0.7 |
| THC-COOH | 6.3 | 9.3 | 5.6 | 0.8 | −7.2 | 0.5 |
aDifference between the initial and final concentrations of target compounds.