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Investigation of Continuous Flow Methods for Determining the Content of Reducing Sugar in Tobacco *


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Figure 1.

The pipeline diagram for the revised method.
The pipeline diagram for the revised method.

Figure 2.

The differences in the reducing sugar content between ISO 15154:2003 and the revised method.
The differences in the reducing sugar content between ISO 15154:2003 and the revised method.

Figure 3.

The UV-Vis absorption spectra for standard solutions with different concentrations.
The UV-Vis absorption spectra for standard solutions with different concentrations.

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
eISSN:
2719-9509
Language:
English
Publication timeframe:
4 times per year
Journal Subjects:
General Interest, Life Sciences, other, Physics