| Parameter | Proficiency testing item B-CB11A |
Uncertainty | Proficiency testing item B-CB11B |
Uncertainty | Unit |
| Methyl-tert-butylether | 1.80 | 0.09 | 0.482 | 0.035 | µg/L |
| Benzene | 1.34 | 0.08 | 3.17 | 0.17 | µg/L |
| Toluene | 4.24 | 0.22 | 1.14 | 0.07 | µg/L |
| Ethylbenzene | 1.98 | 0.12 | 4.31 | 0.23 | µg/L |
| Sum of m- and p-Xylene | 3.40 | 0.19 | <0.1 | - | µg/L |
| o-Xylene | 3.00 | 0.16 | 0.81 | 0.06 | µg/L |