Table 3.
Average extinction coefficients (ɛave, with corresponding variation) of carbon nanotubes in 1,2-dichlorobenzene
| Sample | εave ± SD (n = 5) (mL · cm−1 · mg−1) | CV% |
|---|---|---|
| SWNT 1 | 24.9 ± 4.5 | 18.1 |
| SWNT 2 | 30.5 ± 2.3 | 7.5 |
| SWNT 3 | 43.8 ± 3.1 | 7.1 |
| SWNT 4 | 53.1 ± 2.9 | 5.5 |
| SWTN 5 | 51.7 ± 6.6 | 12.8 |
| SWTN 6 | 54.2 ± 3.1 | 5.7 |
| MWNT 1 | 49.0 ± 5.8 | 11.8 |
| MWNT 2 | 51.4 ± 2.9 | 5.6 |
| MWNT 3 | 58.0 ± 7.3 | 12.6 |
| MWNT 4 | 60.9 ± 8.4 | 13.8 |
| MWNT 5 | 49.4 ± 3.2 | 6.5 |
| MWNT 6 | 68.3 ± 2.8 | 4.1 |
| MWNT 7 | 56.3 ± 3.9 | 6.9 |
| MWNT 8 | 61.3 ± 6.9 | 11.3 |
| MWNT 9 | 56.1 ± 5.6 | 10.0 |
| MWNT 10 | 53.5 ± 6.4 | 12.0 |
| MWNT 11 | 55.3 ± 5.8 | 10.5 |
| MWNT 12 | 53.0 ± 4.1 | 7.7 |
Notes: Using the Beer–Lambert Law A = ɛ · c · l, where ultraviolet-visible absorbance at 500 nm (A500) was experimentally determined, concentration (c) represents the stock solution concentrations used in the standard curves, and pathlength (l) was 0.596 cm. [Statistical analysis was performed by one-way analysis of variance followed by a Tukey multiple comparison post-test, significant results: SWNT 1 versus SWNT 3–6 (P < 0.001) and versus MWNT 1–12 (P < 0.001); SWNT 2 versus SWNT 3–6 (P < 0.05) and versus MWNT 1–12 (P < 0.001); SWNT 3 versus MWNT 3, 4, and 6–9 (P < 0.05); MWNT 6 versus SWNT 1–6 (P < 0.01) and versus MWNT 1, 2, 5, and 7–12 (P < 0.05); MWNT 1 versus MWNT 4 and 8 (P < 0.05), MWNT 5 versus MWNT 8 (P < 0.05)].
Abbreviations: CV, coefficient of variation; MWNT, multi-walled carbon nanotubes; SWNT, single-walled carbon nanotubes; SD, standard deviation.