Research Article
Development and Validation of a Method for the Analysis of Zinc Oxide in Cosmetic Matrices by Flame Atomic Absorption Spectroscopy
Table 6
Youden–Steiner design for selected variables of the method.
| | Parameter | Experiment number | | 1 | 2 | 3 | 4 | 5 | 6 | 7 | 8 |
| | Ethanol (mL) | 75 | 65 | 65 | 75 | 75 | 65 | 75 | 65 | | Ultrasound bath temperature (°C) | 55 | 55 | 45 | 45 | 55 | 45 | 45 | 55 | | First sonication step (min) | 15 | 15 | 15 | 30 | 30 | 30 | 15 | 30 | | Second sonication step (min) | 15 | 30 | 30 | 30 | 15 | 15 | 15 | 30 | | Final concentration (ppm) | 0.3 | 0.3 | 0.7 | 0.7 | 0.7 | 0.3 | 0.7 | 0.3 |
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Bold values are the standard conditions of the method.
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