GB/T 19941.3-2019Leather and fur -- Determination of formaldehyde content -- Part 3: Formaldehyde emissions (English PDF)

Foreword

GB/T 19941 "Leather and fur - Determination of formaldehyde content" consists

of the following 3 parts:

- Part 1: High performance liquid chromatography method;

- Part 2: Colorimetric method;

- Part 3: Formaldehyde emissions.

This Part is Part 3 of GB/T 19941.

This Part was drafted in accordance with the rules given in GB/T 1.1-2009.

This Part uses redrafting method by adopting ISO 17226-3:2011 "Leather -

Chemical determination of formaldehyde content - Part 3: Determination of

formaldehyde emissions from leather".

Compared with ISO 17226-3:2011, this Part has more structural adjustments.

Annex A gives a list of comparisons between this Part and I ISO 17226-3:2011

on chapter numbers.

Compared with ISO 17226-3:2011, there are technical differences in this Part.

Annex B gives a list of corresponding technical differences and their reasons.

This Part also made the following editorial modifications:

- changed the standard name to "Leather and fur - Determination of

formaldehyde content - Part 3: Formaldehyde emissions";

- added a note on operation when the formaldehyde content is too high in

6.3;

- modified formula symbol.

This Part was proposed by China National Light Industry Council.

This Part shall be under the jurisdiction of National Technical Committee on

Leather Industry of Standardization Administration of China (SAC/TC 252).

The drafting organizations of this Part: Chongqing Testing and Certification

(Group) Co., Ltd., National Leather Quality Supervision and Inspection Center

(Zhejiang), Foshan Nanhai District Jinda Footwear Company Limited, Test

Instruments (Fujian) Co., Ltd., China Leather and Footwear Research Institute

Co., Ltd., Dongguan Huikeda Footwear Company Limited.

Leather and fur - Determination of formaldehyde

content - Part 3: Formaldehyde emissions

1 Scope

This Part of GB/T 19941 specifies high performance liquid chromatography

(HPLC) method for the determination of formaldehyde emission in leather and

fur.

This Part is applicable to determination of formaldehyde emission in various

leathers, furs and their products.

2 Normative references

The following referenced documents are indispensable for the application of

this document. For dated references, only the edition cited applies. For undated

references, the latest edition of the referenced document (including any

amendments) applies.

GB/T 6682, Water for analytical laboratory use - Specification and test

methods (GB/T 6682-2008, ISO 3696:1987, MOD)

QB/T 1266, Leather - Physical and mechanical tests - Sample preparation

and conditioning (QB/T 1266-2012, ISO 2419:2006, MOD)

QB/T 1267, Fur - Chemical, physical and mechanical and fastness tests -

Sampling location (QB/T 1267-2012, ISO 2418:2002, MOD)

QB/T 1273, Fur - Chemical Tests - Determination of Volatile Matter (QB/T

1273-2012, ISO 4684:2005, MOD)

QB/T 2706, Leather - Chemical physical and mechanical and fastness tests

- Sampling location (QB/T 2706-2005, ISO 2418:2002, MOD)

QB/T 2707, Leather - Physical and mechanical tests - Sample preparation

and conditioning (QB/T 2707-2018, ISO 2419:2012, MOD)

QB/T 2717, Leather - Chemical tests - Determination of volatile (QB/T 2717-

2018, ISO 4684:2005, MOD)

Use the die knife (5.8) to cut 5 samples with a size of 100mmx40mm. In order

to fix the sample, at 10mm from the edge of each sample, make a hole with a

diameter of 3mm~4mm.

5 sample bottles (5.1) containing 50mL of water. Seal. Take another sealed

sample bottle that contains only 50mL of water as a blank. After each sample

bottle is sealed, immediately put into a (60+/-2)°C oven. Place for (180+/-15) min.

Cool the sample bottle at room temperature for 1h. Take out the sample. The

aqueous solution that contains formaldehyde is immediately tested in

accordance with 6.3.

8 Test report

The test report shall contain the following:

a) Reference to this Part;

b) Sample name, number, type, manufacturer (or trademark);

c) Average amount of formaldehyde released, in milligrams per kilogram

(mg/kg);

d) Total number of test samples;

e) Any deviation from the method specified in this Part;

f) If the test result is based on the absolute dry state, it shall be noted in the

report.

Annex C

(normative)

Determination of formaldehyde content in standard stock solution

C.1 Reagents and materials

C.1.1 Formaldehyde solution: mass fraction is about 37%.

C.1.2 Iodine solution: 0.05mol/L, that is 12.68g/L.

C.1.3 Sodium hydroxide solution: 2.0mol/L.

C.1.4 Sulfuric acid solution: 2.0mol/L.

C.1.5 Sodium thiosulfate solution: 0.1mol/L.

C.1.6 Starch solution: 1%, that is, 1g of starch is dissolved in 100mL of distilled

water.

C.2 Instruments and equipment

C.2.1 Volumetric flask: 1000mL.

C.2.2 Erlenmeyer flask: 250mL.

C.2.3 Pipettes: 5mL, 10mL, 50mL.

C.3 Determination method

C.3.1 Preparation of formaldehyde standard stock solution

Transfer 5.0mL of formaldehyde solution (C.1.1) into a 1000mL volumetric flask

(C.2.1) filled with about 100mL of distilled water. Use distilled water to dilute to

the scale. This solution is formaldehyde standard stock solution.

C.3.2 Determination

Pipette 10mL of formaldehyde standard stock solution into a 250mL conical

flask (C.2.2). Add 50mL of iodine solution (C.1.2). After mixing well, add sodium

hydroxide solution (C.1.3) until it turns yellow. Place in an environment of

18°C~26°C (15+/-1) min. Then add 15mL of sulfuric acid solution (C.1.4).

Oscillate. Add 2mL of starch solution (C.1.6). Use sodium thiosulfate solution

(C.1.5) to titrate excessive iodine until the color changes (blue disappears).

Conduct three parallel determinations.

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