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GB/T 7573-2009 (GB/T7573-2009)

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GB/T 7573-2009: PDF in English (GBT 7573-2009)

GB/T 7573-2009
GB
ICS 59. 080. 01
W 04
NATIONAL STANDARD
OF THE PEOPLE'S REPUBLIC OF CHINA
Replacing GB/T 7573-2002
Textiles - Determination of pH of
Aqueous Extract
(ISO 3071. 2005, MOD)
ISSUED ON. JUNE 11, 2009
IMPLEMENTED ON. JANUARY 01, 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 Terms and Definitions ... 5 
4 Principle ... 5 
5 Reagents ... 6 
6 Apparatus ... 6 
7 Preparation of Test Samples ... 7 
8 Measuring Procedures ... 7 
9 Calculation... 8 
10 Precision ... 8 
11 Test Report ... 8 
Appendix A (Informative) Preparation of Standard Buffer Solutions... 10 
Foreword
This Standard modifies and adopts ISO 3071.2005 "Textiles - Determination of pH of
Aqueous Extract". Compared with ISO 3071. 2005, the main differences are as
follows.
— The international standards in Chapter "Normative References" are replaced by
the corresponding national standards.
— 100mL measuring cylinder is added in Chapter "Apparatus".
— Note 1 and Note 2 are added in 8.1.
— "Calibrate the pH meter at the temperature of the extract to be measured. Check
the calibration of the pH meter by using two buffer solutions" in 8.2 is changed to
"The pH meter shall be calibrated at the temperature of extract by using two or
three kinds of buffer solutions".
— Note 2 is added in Chapter 10.
— "a) Descriptions to the samples" is added in Chapter "Test Report".
This Standard shall replace GB/T 7573-2002 "Textiles - Determination of pH of the
Aqueous Extract". Compared with GB/T 7573-2002, the main differences are as
follows.
— Definition of the pH value is added.
— In Chapter "Normative References", "GB/T 6682 Water for Analytical Laboratory
Use - Specification and Test Methods" is added and "GB/T 6529 Standard
Atmospheres for Textiles Conditioning and Testing" is deleted.
— In Chapter 5 "Reagents", the pH value range of distilled water or deionized
water is changed to 5.0~7.5. The provisions on the "maximum electrical
conductivity and boiling for 5 min before using" are deleted. And the
recommended method "water treatment" is added.
— In Chapter 5 "Reagents", the extraction medium of 0.1mol/L potassium chloride
solution and a kind of buffer solution are added. And the preparation of buffer
solutions is adjusted to Appendix A.
— In Chapter 6 "Apparatus", the accuracy of pH meter is changed from 0.05 to 0.1;
and the accuracy of balance is changed from 0.05g to 0.01g.
— The provisions on the humidifying treatment of test samples are deleted.
Textiles - Determination of pH of
Aqueous Extract
1 Scope
This Standard specifies a method for determining the pH value of the aqueous extract
of textiles.
This Standard is applicable to the textiles in any form.
2 Normative References
The following standards contain provisions which, through reference in this text,
constitute provisions of this Standard. For dated references, subsequent amendments
(excluding correction) or revisions of these publications do not apply. However, the
parties who enter into agreement according to these specifications are encouraged to
research whether the latest editions of these labels are applied or not. For undated
references, the latest edition of the normative document is applicable to these
specifications.
GB/T 6682 "Water for Analytical Laboratory Use - Specification and Test
Methods" (GB/T 6682-2008, ISO 3696. 1987, MOD)
3 Terms and Definitions
For the purposes of this Standard, the following terms and definitions apply.
3.1
pH value
The negative logarithm of hydrogen ion concentration in an aqueous extract.
4 Principle
The pH value of an aqueous extract of a textile is measured at room temperature by
means of a pH meter with glass electrode.
e) PH value of the extraction medium;
f) Temperature of extract;
g) Any factors that may affect the results, including the phenomenon resisting the
wetting out of the test samples, etc.;
h) The date of measurement.
Appendix A
(Informative)
Preparation of Standard Buffer Solutions
A.1 General
All the reagents used in the tests are the analytically pure. The water used for
preparing the buffer solutions shall at least meet the requirements of Grade 3 water
specified in GB/T 6682. And the buffer solutions shall be replaced at least once a
month.
A.2 Potassium hydrogen phthalate buffer solution, 0.05 mol/L (pH 4.0)
Weigh 10.21g of potassium hydrogen phthalate (KHC8H4O4); put them into a 1L
volumetric flask and dissolve them with deionized water or distilled water to the scale.
The pH value of this solution is 4.00 at 20°C and 4.01 at 25°C.
A.3 Potassium dihydrogen phosphate and disodium hydrogen phosphate
buffer solution, 0.08 mol/L (pH 6.9)
Weigh 3.9g of potassium dihydrogen phosphate (KH2PO4) and 3.54g of disodium
hydrogen phosphate (Na2HPO4); put them into a 1L volumetric flask and dissolve
them with deionized water or distilled water to the scale. The pH value of this solution
is 6.87 at 20°C and 6.86 at 25°C.
A.4 Sodium tetraborate buffer solution, 0.01 mol/L (pH9.2)
Weigh 3.80g of sodium tetraborate decahydrate (Na2B4O7·10H2O); put them into a 1L
volumetric flask and dissolve them with deionized water or distilled water to the scale.
The pH value of this solution is 9.23 at 20°C and 9.18 at 25°C.
......
 
Source: Above contents are excerpted from the PDF -- translated/reviewed by: www.chinesestandard.net / Wayne Zheng et al.