| Atom | Metronidazole CRS | Sample 1: Holden Wezep | Sample 2: Elys Chemicals | Quinine sulfate CRS | ||
| Theoritical (%) | Experimental (%) (n = 2) mean | Experimental (%) (n = 2) mean | Experimental (%) (n = 2) mean | Theoritical (%) | Experimental (%) (n = 2) mean | |
| N | 24.55 | 25.14 | 22.21 | 20.59 | 7.16 | 7.67 |
| C | 42.1 | 42.11 | 46.00 | 41.85 | 61.36 | 60.89 |
| H | 5.3 | 5.38 | 5.77 | 5.49 | 6.95 | 6.98 |
| S | 0.0 | 0.0 | 0.0 | 0.0 | 4.1 | 3.4 |