Figure 1.
Figure 2.
Figure 3.
The differences in the heating times of the two methods_
| Methods | Heating tank volume | Repeating time | Mean heating time |
|---|---|---|---|
| ISO 15154: 2003 | 7.7 mL | 5 | 3 m 20 s |
| Revised method | 10.6 mL | 5 | 4 m 15 s |
Preparation of solutions for the revised method_
| Number | Reagent | Method |
|---|---|---|
| 1 | 0.2 mol@L-1 Hydrochloric acid | Add 16.8 mL hydrochloric acid (mass ratio 37%) to 500 mL water, followed by one drop of Brij-35, and dilute the solution to 1 L with water |
| 2 | 0.4 mol@L-1 sodium hydroxide | Add 16 g sodium hydroxide to 800 mL water, stir until dissolved, then natural cooling to room temperature, followed by one drop of Brij-35, and dilute the solution to 1 L with water |
The detection ability of the two methods for different sample cups_
| Method | Project | 1st cup | 10th cup | 20th cup | 30th cup | 40th cup | 50th cup | 60th cup | 70th cup | 80th cup | 90th cup |
|---|---|---|---|---|---|---|---|---|---|---|---|
| ISO15154: 2003 | Reducing-sugar (%) | 7.52 | 7.30 | 7.22 | 7.20 | 7.17 | 7.13 | 6.72 | 6.55 | 6.48 | 6.45 |
| Differences (%) | / | −0.22 | −0.30 | −0.32 | −0.35 | −0.39 | −0.80 | −0.97 | −1.04 | −1.07 | |
| Revised method | Reducing-sugar (%) | 7.44 | 7.29 | 7.44 | 7.37 | 7.35 | 7.26 | 7.31 | 7.35 | 7.28 | 7.41 |
| Differences (%) | / | −0.15 | 0 | −0.07 | −0.09 | −0.18 | −0.13 | −0.09 | −0.16 | −0.03 |
Comparison of the two methods_
| Sample | Parallel measurement times | Reducing sugar (%) | F | Critical value of F | |
|---|---|---|---|---|---|
| ISO 15154: 2003 | Revised method | ||||
| A | 5 | 26.18 | 26.04 | 1.94 | 5.98 |
| B | 5 | 0.54 | 0.5 | 3.00 | |
| C | 5 | 24.45 | 24.68 | 0.88 | |
| D | 5 | 7.78 | 7.89 | 1.36 | |
| E | 5 | 11.18 | 11.31 | 1.56 | |
| F | 5 | 22.41 | 22.19 | 2.18 | |
| G | 5 | 9.98 | 10.05 | 2.02 | |
The precision of the method_
| Sample | Reducing sugar (%) | RSD (%) | |
|---|---|---|---|
| Within-day | Inter-day | ||
| A | 26.21 | 2.42 | 3.04 |
| B | 0.52 | 3.94 | 4.24 |
| F | 8.08 | 3.45 | 3.60 |
The number of heating tanks required for analyzing samples using the two methods_
| Method | Heating tank consumption | Sample quantity |
|---|---|---|
| ISO 15154: 2003 | 4 | 3600 |
| Revised method | 2 | 4500 |
The recovery rate of the revised method_
| Sample | Reducing sugar(%) | Addition content (%) | Revised method | |
|---|---|---|---|---|
| Results (%) | Recovery rate (%) | |||
| A | 26.21 | 20.97 | 48.20 | 102.16 |
| 26.21 | 26.21 | 52.76 | 100.65 | |
| 26.21 | 31.45 | 57.59 | 99.87 | |
| F | 8.08 | 6.46 | 14.28 | 98.22 |
| 8.08 | 8.08 | 16.09 | 99.54 | |
| 8.08 | 9.70 | 18.43 | 103.65 | |
| G | 12.10 | 9.68 | 21.44 | 98.46 |
| 12.10 | 12.10 | 23.92 | 98.86 | |
| 12.10 | 14.52 | 26.93 | 101.18 | |
The r and R values of the revised method_
| Sample | Mean content (%) | | r | R |
|---|---|---|---|
| A | 26.14 | 1.3 | 5.2 |
| B | 0.52 | 0.4 | 0.6 |
| F | 8.07 | 1.2 | 2.9 |
Improvements in the method to determine reducing sugars in tobacco_
| Item | ISO 15154: 2003 | Revised method | |
|---|---|---|---|
| 1 | Reagent | 5% acetic acid | 0.2 mol@L-1 hydrochloric acid |
| 2 | Pipeline | Blu/blu 1.60 cm3@min-1 | Red/red 0.80 cm3@min-1 |
| 3 | NaOH concentration | 0.5 mol@L-1 | 0.4 mol@L-1 |
| 4 | Heating tank volume | 7.7 mL | 10.6 mL |