GB/T 2912.1-2009 English PDF (GBT2912.1-2009)

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GB/T 2912.1-2009: Textiles -- Determination of formaldehyde -- Part 1: Free and hydrolyzed formaldehyde (water extraction method)
GB/T 2912.1-2009
GB
ICS 59.080.01
W 04
NATIONAL STANDARD
OF THE PEOPLE’S REPUBLIC OF CHINA
Replacing GB/T 2912.1-1998
Textile - Determination of Formaldehyde - Part 1.
Free and Hydrolyzed Formaldehyde
(Water Extraction Method)
(ISO 14184-1.1998, MOD)
ISSUED ON. JUNE 11, 2006
IMPLEMENTED ON. JANUARY 1, 2010
Jointly issued by. General Administration of Quality Supervision,
Inspection and Quarantine (AQSIQ);
Standardization Administration (SAC) of the People’s
Republic of China.
Table of Contents
Foreword ... 3 
1 Scope ... 5 
2 Normative References ... 5 
3 Principle ... 6 
4 Reagents ... 6 
5 Apparatus ... 6 
6 Preparation of Formaldehyde Standard Solution and Standard Curve ... 7 
7 Specimen Preparation ... 8 
8 Procedures ... 9 
9 Calculation and Expression of the Results ... 10 
10 Test Report ... 11 
Appendix A (Normative) Standardization of Formaldehyde Stock Solution – ... 12 
Sodium Sulfite Method ... 12 
Appendix B (Normative) Standardization of Formaldehyde Stock Solution – Iodometry ... 14 
Appendix C (Informative) Information on Accuracy of the Method ... 17 
Corrigendum... 17 
Foreword
GB/T 2912 "Textile - Determination of formaldehyde" is divided into 3 parts.
- Part 1. Free and hydrolyzed formaldehyde (water extraction method);
- Part 2. Released formaldehyde (vapor absorption method);
- Part 3. High performance liquid chromatography method.
This Part is Part 1 of GB/T 2912.
Adopting re-drafting method, this Part modifies and adopts ISO 14184-1.1998 "Textile
- Determination of formaldehyde - Part 1. Free and hydrolyzed formaldehyde (water
extraction method)" (English version).
Compared with ISO 14184-1.1998, the differences of this Part are as follows.
- International standards are replaced by Chinese standards for normative
references;
- Delete the foreword of the international standard;
- Add the detailed descriptions in principle;
- Add requirements that the calculation results shall be rounded off to integers;
- Add Annendix B “formaldehyde stock solution calibration method – iodometry”.
This Part replaces GB/T 2912.1-1998 "Textile - Determination of formaldehyde - Part
1. Free and hydrolyzed formaldehyde (water extraction method)".
Compared with GB/T 2912.1-1998, the main changes of this Part are as follows.
- Add detection limit in the Scope;
- Add GB/T 11415 in the Normative References;
- Add the detailed descriptions in principle;
- Change the specimen’s quantity from 3 to 2. Add requirements that the
calculation results shall be rounded off to integers;
- In Chapter 9, add "If the result is less than 20 mg/kg, test result shall be reported
as 'not detectable";
Textile - Determination of Formaldehyde-
Part 1. Free and Hydrolyzed Formaldehyde
(Water Extraction Method)
Warning. The personnel using this Part of GB/T 2912 shall have practical
experiences in regular laboratory work. This Part does not point out all the
possible safety problems. Users have the responsibility to take appropriate
safety and health measures and also ensure meeting the conditions specified in
relevant regulations of the State.
1 Scope
This Part of GB/T 2912 specifies a method for determining the amount of free
formaldehyde extracted through water extraction method and partly through
hydrolysis.
This Part is applicable to the textile samples in any form.
This Part is applicable to the textiles with free formaldehyde content between
20mg/kg~3500 mg/kg. The lower limit is 20 mg/kg. Below this limit the result is
reported as 'not detectable'.
2 Normative References
The following standards contain provisions which, through reference in this Part of
GB/T 2912, constitute provisions of this standard. For dated reference, subsequent
amendments (excluding correction) or revisions of these publications do not apply.
However, the parties who enter into agreement based on this standard are
encouraged to investigate the possibility of applying the most recent editions of the
standards. For undated references, the latest edition of the normative document
referred to applies.
GB/T 6529 Textiles - Standard atmospheres for conditioning and testing (GB/T
6529-2008, ISO 139.2005, MOD)
GB/T 6682 Water for analytical laboratory use - Specification and test methods
(GB/T 6682-2008, ISO 3696.1987, MOD)
GB/T 11415 Laboratory sintered (fritted) filters - Porosity grading, classification
Appendix B (Normative)
Standardization of Formaldehyde Stock Solution – Iodometry
B.1 General
The stock solution containing approximately 1500μg/mL formaldehyde shall be
accurately standardized in order to prepare a precise working curve for use in
colorimetric analysis.
B.2 Principle
An aliquot of the stock solution is reacted with an excess of iodine solution. Use
standard acid solution, with thymolphthalein as indicator, to carry out the back-titration.
B.3 Apparatus
B.3.1 5 mL, 10 mL, 20 mL, 50 mL one-mark pipette.
B.3.2 50 mL burette.
B.3.3 250 mL iodine flask and conical flask with stopper.
B.3.4 500 mL, 1L volumetric flask.
B.4 Reagents
B.4.1 Iodine solution [c(I2)=0.1 mol/L]. put 13 g of iodine (I2) and 30 g of potassium
iodide (KI) into a 1 L brown volumetric flask. Dilute to the mark with water. Shake well
and store in the dark place.
B.4.2 Sodium hydroxide. c(NaOH)=1 mol/L.
B.4.3 Sulfuric acid. c(H2SO4)=0.5 mol/L.
B.4.4 Starch indicator. dissolve 0.5g of soluble starch into 100mL water. Boil for 2
min. Prepare it before use.
B.4.5 Sodium thiosulfate solution [c(Na2S2O3)=0.1 mol/L]. weigh 25 g of
Na2S2O3·5H2O (or 16 g of anhydrous Na2S2O3). Dissolve it into 1L of water that has
been boiled and cooled freshly, and that is added with 0.1g of anhydrous sodium
carbonate. Stir to dissolve. Store in a brown bottle.
c1 - Concentration of Na2S2O3 standard solution, mol/L;
0.015 - Mass of formaldehyde equivalent to 1 mL of Na2S2O3 (c=1.0000 mol/L)
standard solution, g;
V - Volume of formaldehyde solution used, mL.
Calculate the mean of the results and use the concentration determined above in
preparing the working curve for the colorimetric analysis.
Appendix C (Informative)
Information on Accuracy of the Method
This method is based on a Finnish method for which the accuracy of the test was
found to depend on the formaldehyde content of the specimen and to be as follows for
uniform samples.
Formaldehyde content, mg/kg Accuracy, %
1000 0.5
100 2.5
Based on above, when contents of formaldehyde is lower than 20 mg/kg, it cannot be
shown.
Note. the calibration curve in this Part is different from the curve made of above
mentioned results.
Corrigendum.
GB/T 2912.1-2009 Textile - Determination of Formaldehyde - Part 1. Free and
Hydrolyzed Formaldehyde (Water Extraction Method)
GB/T 2912.2-2009 Textiles - Determination of Formaldehyde - Part 2. Released
Formaldehyde (Vapour Absorption Method)
A.4.1 in Appendix A
“Sodium sulfite [c(Na2S2O3)=0.1 mol/L]” molecular concentration shall be corrected to be
“Sodium sulfite [c(Na2SO3)=1 mol/L]”.