GB/T 7573-2025 Textiles - Determination of pH of aqueous extract
1 Scope
This document describes the methods for determination of pH of aqueous extract for textiles.
This document is applicable to all kinds of textile products (e.g., fillings such as fibers, yarns, fabrics, down, etc.).
2 Normative references
The following documents contain provisions which, through reference in this text, constitute provisions 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)
3 Terms and definitions
For the purposes of this document, the following terms and definitions apply.
3.1
pH value
negative logarithm of hydrogen ion concentration in aqueous extract
4 Principle
Determine the pH value of the aqueous extract for textile at room temperature by a pH meter with a glass electrode.
5 Reagents
All reagents are analytically pure.
5.1 Distilled water or deionized water, which at least meets the requirements for Grade III in GB/T 6682, and its pH value is between 5.0 and 7.5. The pH value of the water shall be checked before the first use. If the pH value is not within the specified range, re-distillation shall be conducted by chemically stable glassware. The acid or organic material may be removed by distillation of 1 g/L potassium permanganate and 4 g/L sodium hydroxide solution. The alkali (e.g. in the presence of ammonia) may be removed by distillation of dilute sulfuric acid. If the distilled water is not Grade III water, the distilled water may be boiled in a beaker at an appropriate rate for (10 ± 1) min and cooled to room temperature with the lid covered.
Foreword i
1 Scope
2 Normative references
3 Terms and definitions
4 Principle
5 Reagents
6 Apparatus
7 Preparation of specimen
8 Determination steps
9 Calculation and expression of results
10 Accuracy
11 Test report
Annex A (Informative) Preparation of standard buffer solutions
Bibliography
