GB 31604.32-2016 PDF English
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| Standard ID | Contents [version] | USD | STEP2 | [PDF] delivery | Name of Chinese Standard | Status |
| GB 31604.32-2016 | English | 70 |
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National food safety standard - Food contact materials and products - Determination of heavy metals in food simulants
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GB 31604.32-2016: National food safety standard - Food contact materials and products - Determination of heavy metals in food simulants
---This is an excerpt. Full copy of true-PDF in English version (including equations, symbols, images, flow-chart, tables, and figures etc.), auto-downloaded/delivered in 9 seconds, can be purchased online: https://www.ChineseStandard.net/PDF.aspx/GB31604.32-2016
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].
3.2 Reagent preparation
3.2.1 Hydrochloric acid solution (1+1, volume ratio). TAKE 100mL of
hydrochloric acid; carefully ADD it into 100mL of water; MIX it uniformly.
3.3 Standards
Iodine standard solution [(2 1 I2) = 0.1mol/L]. According to GB/T 601 prepare
and standardize or commercialize products.
4 Instrument and equipment
4.1 Analytical balance. sensitivity is 0.1mg.
4.4 Iodine volumetric flask.
4.5 Electric planer or chainsaw.
4.6 Crusher.
5 Analytical procedures
5.1 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
INDICATE the mark. During the operation of sample preparation, the sample
shall be protected from sulfur dioxide contamination.
5.2 Distillation
WEIGH 5g of sample (accurate to 0.01g); PLACE it in 500mL round-bottomed
flask.
5.3 Titration
ADD 10mL of hydrochloric acid and 1mL of starch indicator (10g/L)
successively into iodine volumetric flask. After shake it well, USE iodine
standard solution (0.01mol/L) to titrate until the solution turns blue and does
not fade within 30 seconds.
6 Analysis results expression
The content of sulfur dioxide in the sample is calculated according to formula
(1).
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.
9 Principles
Acidify the sample in a closed vessel; heat and distill it to release sulfur dioxide
therein.
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.
10.1 Reagents
10.2 Reagent preparation
10.2.1 Potassium mercuric tetrachloride absorber solution (0.04mol/L).
WEIGH 10.86g of mercuric chloride, 0.066g of disodium EDTA, 5.96g of
potassium chloride, DISSOLVE it in water and DILUTE it to 1000mL.
10.2.2 Sulfamic acid solution (6g/L). WEIGH 0.6g of sulfamic acid and
DISSOLVE it in 100mL of water; PREPARE it before use.
10.2.3 Formaldehyde solution (2g/L). PIPETTE 1mL of formaldehyde; USE
water to dilute it to 200mL; STORE it in stoppered glass bottle; PREPARE it
before use.
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.
11.7 Water bath kettle.
......
Source: Above contents are excerpted from the full-copy PDF -- translated/reviewed by: www.ChineseStandard.net / Wayne Zheng et al.
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