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GB 31604.32-2016

Chinese Standard: 'GB 31604.32-2016'
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GB 31604.32-2016English70 Add to Cart 0--10 minutes. Auto immediate delivery. Food contact materials for export. Wood materials. Determination of sulfur dioxide Valid GB 31604.32-2016
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Detail Information of GB 31604.32-2016; GB31604.32-2016
Description (Translated English): Food contact materials for export. Wood materials. Determination of sulfur dioxide
Sector / Industry: National Standard
Classification of Chinese Standard: X09
Word Count Estimation: 8,848
Date of Issue: 2016-10-19
Date of Implementation: 2017-04-19
Older Standard (superseded by this standard): SN/T 2827-2011 Partially
Regulation (derived from): State Health and Family Planning Commission Notice No.1516 of 2016

GB 31604.32-2016
GB
NATIONAL STANDARD OF THE
PEOPLE’S REPUBLIC OF CHINA
National food safety standard -
Food contact materials and products -
Determination of sulfur dioxide in wood materials
ISSUED ON. OCTOBER 19, 2016
IMPLEMENTED ON. APRIL 19, 2017
Issued by. National Health and Family Planning Commission of the PRC
Table of Contents
Foreword ... 3 
1 Scope ... 4 
2 Principles ... 4 
3 Reagents and materials ... 4 
4 Instrument and equipment ... 5 
5 Analytical procedures ... 5 
6 Analysis results expression ... 6 
7 Precision ... 7 
8. Others ... 7 
9 Principles ... 7 
10 Reagents and materials ... 7 
11 Instrument and equipment ... 9 
12 Analytical procedures ... 9 
13 Analysis results expression ... 10 
14 Precision ... 11 
15 Others ... 11 
Appendix A Preparation of sulfur dioxide standard solution ... 12 
Foreword
This standard replaces the determination of sulfur dioxide in SN/T 2827-2011
“Food contact materials for export - Wood materials - Determination of sulfur
dioxide”.
Compared with SN/T 2827-2011, the main changes of this standard are as
follows.
-- The standard name has been changed to “National food safety standard -
Food contact materials and products - Determination of sulfur dioxide in
wood materials”;
-- Modify "method summary" in Method I into "principles";
-- Modify "results calculation and expression" in Method I into "analysis
results expression";
-- Modify the formula in Method I;
-- Modify "method summary" in Method II into "principles" and revise the
text;
-- Modify "results calculation and expression" in Method II into "analysis
results expression" and revise the text.
National food safety standard -
Food contact materials and products -
Determination of sulfur dioxide in wood materials
1 Scope
This standard specifies the determination methods for titration and colorimetry
of sulfur dioxide in food contact wood (bamboo) materials.
This standard applies to the determination of sulfur dioxide in wood (bamboo)
chopsticks, wood (bamboo) bowls, wood (bamboo) spoons and wood (bamboo)
shovels.
Method I Titration
2 Principles
Acidify the sample in a closed vessel; heat and distill it to release sulfur dioxide
therein. Use lead acetate solution to absorb the released substance. After
absorption, use concentrated hydrochloric acid to acidify and then titrate with
iodine standard solution. According to the consumed amount of iodine
standard solution, calculate the content of sulfur dioxide in the sample.
3 Reagents and materials
Unless otherwise indicated, the reagents used in this method are analytical
grade, the water is the grade-3 water specified in GB/T 6682.
3.1 Reagents
3.1.1 Hydrochloric acid (HCl).
3.1.2 Lead acetate [Pb(CH3COO)2.3H2O].
3.1.3 Iodine (I2).
3.1.4 Soluble starch [(C6H10O5)n].
V2 - The volume of iodine standard titration solution used for titration reagent
blank, in milliliters (mL);
c - The concentration of iodine standard titration solution, in mole per liter
(mol/L);
0.032 - 1mL iodine standard solution [(( 2
1 I2 = 1.0mol/L] equivalent to the
mass of sulfur dioxide, in grams per mole (g/mol);
1000 - Conversion factor;
m - The mass of the sample, in grams (g).
The calculation result is retained with three significant figures.
7 Precision
The absolute difference between two independent determinations obtained
under repeatability conditions shall not exceed 10% of the arithmetic mean.
8. Others
The method detection limit is 10mg/kg.
Method II Colorimetry
9 Principles
Acidify the sample in a closed vessel; heat and distill it to release sulfur dioxide
therein. Sulfur dioxide is absorbed by potassium mercuric tetrachloride to form
stable complex, which is then reacted with formaldehyde and pararosaniline
hydrochloride to form rose-purple compound for colorimetric determination.
10 Reagents and materials
Unless otherwise indicated, the reagents used in this method are analytical
grade, the water is the grade-3 water specified in GB/T 6682. The potassium
mercuric tetrachloride solution is highly toxic. Wear rubber gloves when
handling. If it splashes on the skin, rinse immediately with water.
solution into 250mL volumetric flask; USE water to dilute it to the mark. This
solution can be stored in dark place for 6 months...
10.3 Standard solution preparation
10.3.1 Sulfur dioxide standard solution. See Appendix A for preparation.
10.3.2 Sulfur dioxide standard working solution. According to the calculation
result of standardization, use potassium mercuric tetrachloride absorber
solution (10.2.1) to dilute sulfur dioxide standard solution (10.3.1) to 1mL which
is equivalent to 5μg of sulfur dioxide; STORE it at 0°C~4°C for 1 month.
11 Instrument and equipment
11.1 UV-visible spectrophotometer.
11.2 Analytical balance. Sensitivity is 0.1mg.
11.3 All-glass distiller.
11.4 Iodine volumetric flask.
11.5 Electric planer or chainsaw.
11.6 Crusher.
11.7 Water bath kettle.
12 Analytical procedures
12.1 Sample preparation
USE electric planer or chainsaw to take 3mm thick out of the surface of the
sample; CRUSH; PLACE it in a clean container. SEAL it as the sample and <......
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