| S/N | Standards (ppm) | Absorbance |
| 1 | 10 | 0.60 |
| 2 | 20 | 0.70 |
| 3 | 40 | 0.75 |
| 4 | 50 | 0.80 |
| 5 | 100 | 0.95 |
| 6 | 200 | 1.15 |
| 7 | 300 | 1.30 |
| 8 | 400 | 1.35 |
| 9 | 500 | 1,45 |
| 10 | 1000 | 1.60 |