Research Article
Modification of Multiwalled Carbon Nanotubes by Dipyridile Amine for Potentiometric Determination of Lead(II) Ions in Environmental Samples
Table 3
The lifetime of the electrode no. 14 and electrode no. 10. The results are based on triplicate measurements.
| | Week |
Electrode no. 14 |
Electrode no. 10 | | Slope (mV) | Detection limit (mol L−1) | Slope (mV) | Detection limit
(mol L−1) |
| | First | 28.6 | 7.0 × 10−8 | 28.9 | 4.5 × 10−8 | | Second | 28.5 | 7.5 × 10−8 | 28.0 | 8.9 × 10−8 | | Third | 28.3 | 8.1 × 10−8 | 27.5 | 1.9 × 10−7 | | Fourth | 28.0 | 9.6 × 10−8 | 25.1 | 5.9 × 10−7 | | Fifth | 27.7 | 2.0 × 10−7 | 16.2 | — | | Sixth | 27.1 | 5.1 × 10−7 | — | — | | Seventh | 26.7 | 8.1 × 10−7 | — | — | | Eighth | 26.1 | 8.9 × 10−7 | — | — | | Ninth | 25.6 | 9.5 × 10−7 | — | — | | Tenth | 25.2 | 1.3 × 10−6 | — | — | | Eleventh | 22.1 | — | — | — |
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