| TMEs | Analysis technique | Contact time (min) | Equilibrium time (min) | References |
| Zn2+ | AAS | 10 - 640 | 50 | Bhatti et al. [3] |
| Cd2+, Pb2+ | Gamma Spectrometry | 10 - 60 | 40 | Sharma et al. [8] |
| Ag+ | - | 5, 20, 35, 50 | 20 | Araujo et al. [13] |
| Ni2+ | AAS | 5 - 100 | 60 | Kumar et al. [19] |
| Cu2+, Ni2+, Zn2+ | UV Spectrophotometry | 0 - 250 | 240 (Cu2+); 60 (Ni2+) 180 (Zn2+) | Kalavathy and Miranda [2] |