Comparison of some of the reported analytical methods used for detecting urea.
| Method | Linear range | Detection limit | Comments | Ref. |
|---|---|---|---|---|
| Fluorescence | 0.25–5 mmol L−1 | 0.01 mmol L−1 | Low sensitivity | 1 |
| Electrochemistry | 1.5–1000 μmol L−1 | 60 nmol L−1 | Wide linear range and sensitivity | 3 |
| Colorimetry | 0.02–0.4 mmol L−1 | 5 μmol L−1 | Simple, but low sensitivity | 7 |
| Chemilumine-scence | 0.002–1.0 μg mL−1 | 0.7 ng mL−1 | Wide linear range, sensitive | 9 |
| SERS | 1–20 mmol L−1 | — | Low sensitivity | 10 |
| RRS | 7.58 × 10−3–0.91 mg mL−1 | 3.51 μg mL−1 | High sensitivity, complex | 11 |
| RRS | 6.66–233.10 nmoL L−1 | 2.0 nmoL L−1 | Simple, sensitive | This method |