Table 1.
UV–visible spectrophotometric parameters of molecules tested and retention rates. Molecules tested were suspended in sterile distilled water (pH 7). Calibration curves were established for each molecule on a UV–visible spectrophotometer within a 180–640 nm wavelength window. The concentrations tested ranged from 10−7 mol L−1 to 10−2 mol L−1 except for trypan blue (TB) and neutral red (NR) for which concentrations ranged from 10−7 mol L−1 to 4.1 × 10−4 mol L−1 and from 5 × 10−4 mol L−1 to 5 × 10−4 mol L−1, respectively. Regression analyses were then performed to determine specific spectrophotometric parameters: (i) linearity limits (mol L−1), (ii) minimum detection limits (mol L−1); within these limits, (iii) the specific maximal absorption wavelength (λmax, nm) and (iv) the specific molar absorption coefficient (ɛ, L mol−1 cm−1). Retention rates (see formula in Section 3.1.1) of each molecule by the specified type of Sephadex™ media are indicated, i.e. TB and chlorhexidine (CHX) Retention rates by Sephadex™ G-25; NR and hexamidine (HXM) Retention rates by Sephadex™ G-10. Ci corresponds to the initial concentration or concentration before filtration. Absorption wavelength used to estimate the retention rate is specified each time it was necessary.
| Molecules tested | Specific spectrophometric parameters for each molecule tested |
Retention rate |
||||
|---|---|---|---|---|---|---|
| λmax (nm) | ɛ (L cm−1 mol−1) | Linearity limits (mol L−1) | Detection limit (mol L−1) | Ci (mol L−1) | Retention rates (%) | |
| Sephadex™ G-25 | ||||||
| TB | 234 | 2.0 × 104 | [2.5 × 10−6 to 10−4] | 5 × 10−7 | 4.1 × 10−4 | 589 nm: 95.11 ± 2.35 (n = 20) |
| 317 | 1.1 × 104 | [2.5 × 10−6 to 10−4] | 7.5 × 10−7 | 4.1 × 10−3 | 589 nm: 92.06 ± 3.43 (n = 20) | |
| 589 | 2.9 × 104 | [5 × 10−7 to 7.5 × 10−5] | 5 × 10−7 | |||
| CHX | 232 | 2.6 × 104 | [10−6 to 2.5 × 10−4] | 10−6 | 10−4, 10−3 | 232 nm, 255 nm: >99a (n = 6) |
| 255 | 2.5 × 104 | [10−6 to 10−4] | 10−6 | 10−2 | 232 nm: 79.73 ± 4.37 (n = 6) | |
| 255 nm: 81.27 ± 1.28 (n = 6) | ||||||
| Sephadex™ G-10 | ||||||
| NR | 276 | 3.5 × 104 | [5 × 10−7 to 5 × 10−5] | 5 × 10−7 | 10−4, 10−3 | 276 nm, 452 nm: >99.5a (n = 20) |
| 452 | 1.0 × 104 | [5 × 10−7 to 5 × 10−5] | 5 × 10−7 | |||
| HXM | 261 | 2.1 × 104 | [10−6 – 10−4] | 10−6 | 10−4, 10−3 | 261 nm: >99a (n = 6) |
| 10−2 | 261 nm: < 90b (n = 6) | |||||
Below the detection limit.
Above the linearity limits.