| Parameter | Proficiency testing item B-CB12A |
Uncertainty | Proficiency testing item B-CB12B |
Uncertainty | Unit |
| Methyl-tert-butylether | 0.96 | 0.06 | 3.45 | 0.18 | µg/L |
| Benzene | 0.83 | 0.05 | 2.70 | 0.14 | µg/L |
| Toluene | 1.39 | 0.08 | 3.39 | 0.18 | µg/L |
| Ethylbenzene | <0.1 | - | 1.46 | 0.08 | µg/L |
| Sum of m- and p-Xylene | 2.50 | 0.13 | 0.79 | 0.05 | µg/L |
| o-Xylene | 1.03 | 0.08 | 4.24 | 0.23 | µg/L |