Table 4 CRM and inter-laboratory test results for VOCs
Compounds | CRM | Proficiency test | ||||||
|---|---|---|---|---|---|---|---|---|
Certified value (μg/L) | Measured value (μg/L) | Recovery (%) | RSD (%) | Reported value (μg/L) | Assigned value (μg/L) | SDPA (μg/L) | z-score | |
Dichloromethane | 54.6 | 52.44 ± 1.14 | 96.0 | 1.82 | < 6.00 | < 6.00 | – | – |
1,1-Dichloroethane | 42.4 | 43.18 ± 1.84 | 101.8 | 3.22 | 33.34 | 38.3 | 8.0 | − 0.618 |
Trichloromethane | 83.1 | 90.87 ± 1.44 | 109.43 | 1.47 | 63.90 | 55.8 | 4.9 | 1.640 |
1,2-Dichloroethane | 48.0 | 47.77 ± 0.33 | 99.5 | 0.69 | 115.3 | 118.0 | 3.9 | − 0.735 |
Benzene | 17.0 | 18.68 ± 0.33 | 109.9 | 1.79 | 83.41 | 74.6 | 12.1 | 0.729 |
Trichloroethene | 75.2 | 80.59 ± 1.71 | 107.2 | 2.00 | 90.12 | 81.2 | 11.2 | 0.796 |
Bromodichloromethane | 41.2 | 40.47 ± 0.39 | 98.2 | 0.95 | 61.84 | 65.2 | 5.5 | − 0.611 |
Toluene | 11.0 | 11.04 ± 0.19 | 100.4 | 1.72 | 16.98 | 18.4 | 7.3 | − 0.190 |
Dibromochloromethane | < 6.00 | 0.53 ± 0.01 | – | 0.83 | 72.05 | 73.9 | 7.7 | − 0.237 |
Tetrachloroethene | 31.3 | 33.92 ± 0.02 | 108.4 | 2.45 | < 4.30 | < 4.30 | – | – |
Tetrachloromethane | 30.4 | 29.77 ± 0.42 | 97.9 | 0.71 | 82.72 | 104.0 | 28.1 | − 0.743 |
1,1,1,2-Tetrachloroethane | 59.7 | 60.97 ± 0.42 | 102.1 | 0.68 | 139.8 | 130.5 | 18.3 | 0.509 |
Ethylbenzene | 19.4 | 19.98 ± 0.31 | 103.0 | 1.56 | < 7.00 | < 7.00 | – | – |
P&M-Xylene | 57.3 | 57.31 ± 0.83 | 100.0 | 1.45 | 62.22 | 54.7 | 9.3 | 0.808 |
Styrene | 40.8 | 35.85 ± 0.32 | 87.9 | 0.88 | < 13.00 | < 13.00 | – | – |
O-Xylene | 21.0 | 20.50 ± 0.19 | 97.6 | 0.94 | 82.81 | 74.1 | 11.7 | 0.745 |
Tribromomethane | 85.6 | 75.26 ± 0.76 | 87.9 | 1.01 | 55.29 | 57.3 | 4.5 | − 0.452 |
1,1,2,2-Tetrachloroethane | 63.9 | 55.65 ± 0.76 | 87.1 | 1.37 | 62.95 | 65.9 | 13.2 | − 0.225 |
Isopropylbenzene | 62.7 | 60.34 ± 0.70 | 96.2 | 1.00 | < 5.00 | < 5.00 | – | – |
N-Propylbenzene | 9.19 | 9.10 ± 0.16 | 99.0 | 1.73 | < 5.00 | < 5.00 | – | – |
1,3,5-Trimethylbenzene | 37.5 | 38.54 ± 0.56 | 102.8 | 1.46 | 95.76 | 69.1 | 18.6 | 1.430 |
1,2,4-Trimethylbenzene | 23.3 | 20.09 ± 0.27 | 86.2 | 1.33 | 76.36 | 64.0 | 15.7 | 0.786 |
1,3-Dichlorobenzene | 50.4 | 45.26 ± 0.42 | 89.8 | 0.93 | 21.68 | 20.9 | 6.3 | 0.123 |
1,4-Dichlorobenzene | 32.4 | 28.54 ± 0.30 | 88.1 | 1.04 | 93.97 | 79.0 | 15.2 | 0.987 |
1,2-Dichlorobenzene | < 7.00 | 0.08 ± 0.01 | – | 8.07 | 104,0 | 91.3 | 15.4 | 0.825 |
1,2,4-Trichlorobenzene | 49.4 | 39.67 ± 1.50 | 80.3 | 3.77 | 53.67 | 45.4 | 7.9 | 1.040 |
Naphthalene | < 6.30 | 0.25 ± 0.02 | – | 9.75 | 66.51 | 62.8 | 12.3 | 0.298 |
Hexachloro-1,3-butadiene | < 4.30 | 0.06 ± 0.01 | – | 5.03 | 50.74 | 46.7 | 15.8 | 0.258 |
1,2,3-Trichlorobenzene | < 5.00 | 0.33 ± 0.02 | – | 8.04 | < 5.00 | < 5.00 | – | – |