Table 7. Experimental Design According to CCD and Experimental and Predicted Values of Recovery (%) (Number of Independent Parameters: 2; Number of Runs: 11; and Number of Center Points: 3).
| recovery |
||||
|---|---|---|---|---|
| run | conc. of HNO3 (M) | time (min) | experimental (%) | predicted (%) |
| 1 | 0.095 | 25.000 | 22.0 | 22.29 |
| 2 | 1.000 | 10.000 | 52.0 | 60.67 |
| 3 | 1.155 | 25.000 | 97.7 | 89.34 |
| 4 | 0.625 | 25.000 | 11.4 | 10.67 |
| 5 | 0.625 | 25.000 | 14.0 | 10.67 |
| 6 | 0.250 | 10.000 | 7.4 | 9.95 |
| 7 | 0.250 | 40.000 | 58.0 | 57.41 |
| 8 | 0.625 | 25.000 | 6.6 | 10.67 |
| 9 | 0.625 | 46.213 | 92.0 | 90.19 |
| 10 | 0.625 | 3.786 | 34.0 | 27.74 |
| 11 | 1.000 | 40.000 | 96.0 | 100.00 |