Figure 1.
Schematic representation of material preparation and presentation of nicotinic dissolution intention.
Table 1.
Operating curve regression equation, LODs, and LOQs of nicotine.
| Target | Linear range (μg × L−1) | Linear regression equation | R2 | LODs (ng × mL−1) | LOQs (ng × mL−1) |
|---|---|---|---|---|---|
| Nicotine | 9.1–182 | y = 0.002826 x- 0.0017 | 0.9999 | 95 | 316 |
Table 2.
Test for precision, repeatability, and stability of the method.
| Target | Primary content (μg) | Additive quantity (μg) | Detection value (μg) | Average recovery (%) | Intraday RSD (%) | Interday RSD (%) |
|---|---|---|---|---|---|---|
| Nicotine | 3152 | 1500 | 4349.6 | 93.5 | 1.4 | 2.1 |
| 3000 | 6459.6 | 105 | 1.5 | 1.9 | ||
| 6000 | 9518.0 | 104 | 0.6 | 0.9 |
Table 3.
FTIR peak wavenumbers, assignments, and interpretations.
| Wavenumber (cm−1) | Assignment | Interpretation |
|---|---|---|
| 3381–3417 | –OH stretch vibration | Hydrogen bond reduction after crosslinking |
| 2923, 2848 | C–H stretch vibration | Aliphatic groups present in all materials |
| 1704 | C=O stretch vibration | Ester bond formation after crosslinking |
| 1645 | C=O stretch vibration | Carboxycarbonyl group |
| 1058, 1110 | C–O–C stretch and bend vibration | Cellulose backbone structure |
| 1031, 1163 | C–OH stretch vibration | Hydroxyl groups in cellulose |
Figure 2.
Synthesis route of BC and CA crosslinking (a). FTIR spectra of aerogels (b) and partially enlarged image (c). The theoretically calculated and experimentally measured CA contents of the materials (d).
Figure 3.
TG curves of BC aerogel material and CA-BC aerogel materials (a). DTG curves of BC aerogel material and CA-BC aerogel materials (b).
Figure 4.
Contact angle of water (a) and water absorption (b) for BC and CA-BC aerogels, and photos acquired after stable droplet deposition of BC (c), 10% CA-BC (d), 20% CA-BC (e) and 100% CA-BC (f).
Figure 5.
Nicotine dissolution curves (a), and nicotine dissolved amount (b), nicotine dissolution rates (c), and fitting rate coefficients (d) of BC and CA-BC aerogels.
Figure 6.
SEM images of BC (a), 10% CA-BC (b), 20% CA-BC (c), and 100% CA-BC (d) aerogels; the pore size distributions of BC (e), 10% CA-BC (f), 20% CA-BC (g), and 100% CA-BC aerogels (h).
Table 4.
Dissolution results of BC and 10% CA-BC at different nicotine contents.
| 2.0 | 1.6 | 1 | 0.4 | 0.2 | ||
|---|---|---|---|---|---|---|
| 10% CA-BC | Dissolution degree (%) | 72.19 | 74.47 | 87.03 | 96.77 | 98.62 |
| Rate coefficient k (min−1) | 0.0345 | 0.0513 | 0.0536 | 0.0728 | 0.0905 | |
| Nicotine dissolution amount (μg) | 2165.7 | 1787.3 | 1305.5 | 580.6 | 295.9 | |
| BC | Dissolution degree (%) | 97.59 | 99.93 | 98.45 | 98.21 | 98.60 |
| Rate coefficient k (min−1) | 0.1546 | 0.1540 | 0.1236 | 0.1230 | 0.1467 | |
| Nicotine dissolution amount (μg) | 2927.7 | 2398.3 | 1476.8 | 589.3 | 295.8 |
Figure 7.
Dissolution curves of 10% CA-BC materials with 0.2%–2.0% nicotine contents (a), fitting curves of the Weibull model to the dissolution results (b), histogram of the dissolution rate coefficient k fitted by the Weibull model (c), and parameter statistics obtained by fitting the Gallagher-Corrigan model (d).
Table 5.
Model fitting results for dissolution profiles of BC and CA-BC aerogels.
| Parameters | BC | 1% CA-BC | 2% CA-BC | 5% CA-BC | 10% CA-BC | 20% CA-BC | 50% CA-BC | 100% CA-BC |
|---|---|---|---|---|---|---|---|---|
| FB/Fmax | 0.9987 | 0.9721 | 0.9253 | 0.9077 | 0.8444 | 0.8059 | 0.9281 | 0.9812 |
| k1 (min−1) | 0.0849 | 0.0538 | 0.0352 | 0.0280 | 0.0201 | 0.0213 | 0.0304 | 0.0720 |
| k2 (min−1) | 1.6163 | 0.8050 | 0.8014 | 0.7539 | 0.5947 | 0.5922 | 0.5858 | 0.8796 |
Figure 8.
Nicotine dissolution amount profiles (a) and nicotine dissolution rates (b) of 10% CA-BC aerogel, snus, and moist snuff.