| Sample No. | Cl− content/ (mg・L−1) | Dilution fold | Theor. COD 500 mg・L−1/ (mg・L−1) | Dilution fold | Theor. COD 1000 mg・L−1/ (mg・L−1) | Dilution fold | Theor. COD 3000 mg・L−1/ (mg・L−1) |
| 1 | 5000 | 10 | 487.3 [−2.5%] | 20 | 992.3 [−0.8%] | 60 | 2887.7 [−3.7%] |
| 2 | 10000 | 10 | 507.5 [1.5%] | 20 | 975.4 [−2.5%] | 60 | 3045.6 [1.5%] |
| 3 | 50000 | 10 | 528.1 [5.6%] | 20 | 999.9 [0.0%] | 60 | 3084.0 [2.8%] |
| 4 | 100,000 | 10 | 537.8 [7.6%] | 20 | 1026.1 [2.6%] | 60 | 3094.9 [3.2%] |
| 5 | 200,000 | 10 | 525.2 [5.0%] | 20 | 10,333.7 [3.4%] | 60 | 3099.7 [3.3%] |