| Sample | pH |
| AMT (0.1 mM) | 6.89 ± 0.03 |
| AMT (0.1 mM) + AMP (0.005 mM) | 5.25 ± 0.03 |
| AMT (0.1 mM) + AMP (0.017 mM) | 4.98 ± 0.02 |
| AMT (0.1 mM) + AMP (0.05 mM) | 4.52 ± 0.00 |
| AMT (0.1 mM) + AMP (0.15 mM) | 4.11 ± 0.01 |
| CPZ (0.1 mM) | 6.21 ± 0.08 |
| CPZ (0.1 mM) + AMP (0.005 mM) | 5.41 ± 0.15 |
| CPZ (0.1 mM) + AMP (0.017 mM) | 5.09 ± 0.01 |
| CPZ (0.1 mM) + AMP (0.05 mM) | 4.54 ± 0.00 |
| CPZ (0.1 mM) + AMP (0.15 mM) | 4.21 ± 0.01 |
| RIS (0.1 mM) | 8.16 ± 0.01 |
| RIS (0.1 mM) + AMP (0.005 mM) | 7.64 ± 0.00 |
| RIS (0.1 mM) + AMP (0.017 mM) | 7.15 ± 0.03 |
| RIS (0.1 mM) + AMP (0.05 mM) | 6.23 ± 0.03 |
| RIS (0.1 mM) + AMP (0.15 mM) | 4.73 ± 0.04 |
| HPD (0.1 mM) | 8.01 ± 0.18 |
| HPD (0.1 mM) + AMP (0.005 mM) | 7.08 ± 0.05 |
| HPD (0.1 mM) + AMP (0.017 mM) | 6.65 ± 0.07 |
| HPD (0.1 mM) + AMP (0.05 mM) | 6.37 ± 0.04 |
| HPD (0.1 mM) + AMP (0.15 mM) | 4.63 ± 0.02 |