Translated English of Chinese Standard: GB/T7573-2009 www.chinesestandard.net Sales@ChineseStandard.net ICS 59. 080. 01 W 04 NATIONAL STANDARD GB OF THE PEOPLE'S REPUBLIC OF CHINA GB/T 7573-2009 Replacing GB/T 7573-2002 Textiles - Determination of ph of Aqueous Extract 纺织品水萃取液 ph 值的测定 (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. www.chinesestandard.net Page 1 of 10
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 www.chinesestandard.net Page 2 of 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. www.chinesestandard.net Page 3 of 10
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. www.chinesestandard.net Page 5 of 10
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. www.chinesestandard.net Page 9 of 10
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 (KHC 8 H 4 O 4 ); 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 (KH 2 PO 4 ) and 3.54g of disodium hydrogen phosphate (Na 2 HPO 4 ); 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 (Na 2 B 4 O 7 10H 2 O); 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. END www.chinesestandard.net Page 10 of 10