Table 1: Determination of Hf(IV) ion in spiked four water samples.
| Sample | Hf(IV) added (ng cm−3) | Hf(IV) found (ng cm−3) | RSD (%) | Recovery (%) | |
| Proposed | ICP-AES | ||||
| Tap sample | 0.00 | NDa | NDa | — | — |
| 40.0 | 41.5 | 39.1 | 1.2 | 103.75 | |
| 80.0 | 78.6 | 81.5 | 1.6 | 98.25 | |
| Mineral water | 0.00 | NDa | NDa | — | — |
| 60.0 | 60.5 | 58.7 | 1.2 | 100.83 | |
| 120 | 118.7 | 121.1 | 1.8 | 98.92 | |
| River water | 0.00 | NDa | NDa | — | — |
| 50.0 | 49.2 | 50.6 | 1.1 | 98.40 | |
| 100 | 101.2 | 102.2 | 1.4 | 101.20 | |
| Waste water | 0.00 | NDa | NDa | — | — |
| 70.0 | 69.6 | 71.4 | 1.3 | 99.43 | |
| 140 | 141.0 | 138.3 | 1.7 | 100.71 | |
| aNot detected. | |||||