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GB 31604.32-2016National food safety standard - Food contact materials and products - Determination of heavy metals in food simulants (English PDF)

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Issued by

National Health and Family Planning Commission of the PRC

Level / Type

National · Mandatory

Issue date

October 19, 2016

Implementation date

April 19, 2017

Scope

GB 31604.32-2016 (National food safety standard - Food contact materials and products - Determination of heavy metals in food simulants) is available as an English-translated PDF.

GB 31604.32-2016 — 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

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Document preview — GB 31604.32-2016

National Standard of the People's Republic of China

Issued by: National Health and Family Planning Commission of the PRC

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.

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This preview omits tables, figures, formulas and parts of the technical clauses. The complete document — 12 pages — is available in the English PDF.

Referenced standards

Cited by

LY/T 3198-2020Binderless bamboo chopping board

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