GB/T 7570-2008Wool -- Determination of acid content (English PDF)

Foreword

This revised standard adopts ISO 3073. 1975 "Determination of acid content of wool." this standard and ISO 3073. 1975 as compared to the main differences are as follows.

1. Added test distilled water requirements;

2. Increasing the calculation result decimal point digits requirements;

3. Modify the acid content of the formula, the concentration of Ba replaced by the symbol T, increasing the molar mass M and K values \u200b\u200bredefined;

4. Increased provisions for experimental error of the results of the request.

This standard replaces GB/T 7570-1987 "Determination of acid content of wool." this standard compared with GB/T 7570-1987, the main changes are as follows.

1. Added test distilled water requirements;

2. Increasing the calculation result decimal point digits requirements;

3. Dry mass of said sample by a 2g to 1g;

4. Modify the formula of acid content, increasing the molar mass M and K values \u200b\u200bredefined.

The standard proposed by China Textile Industry Association.

This standard by the National Standardization Technical Committee Textile basic standards Sub-Committee (SAC/TC209/SC1) centralized.

This standard wool and linen by the Shanghai Textile Research Institute of Science and Technology is responsible for drafting.

1 Scope

This standard specifies the method for determination of acid content of wool.

This standard applies to undyed wool and its products, but also applies to the testing process does not affect the amount of dye staining products titration end point.

2 Normative references

The following documents contain provisions which, through reference in this standard and become the standard terms. For dated references, subsequent Amendments (not including errata content) or revisions do not apply to this standard, however, encourage the parties to the agreement are based on research Whether the latest versions of these documents. For undated reference documents, the latest versions apply to this standard.

Preparation of GB/T 601 chemical reagent standard titration solution GB/T 6682 analytical laboratory use specifications and test methods (GB/T 6682-1992, neq ISO 3696. 1987) GB/T 8170 numerical rounding rules Principle 3 Extracting a certain quality wool with dilute acid pyridine solution, the amount of acid is extracted with sodium hydroxide standard solution titration to calculate containing the amount of acid.

4 Reagents

In the analysis reagents used were of analytical grade and distilled water for the three water GB/T 6682 regulations.

4.1 5g/L of pyridine was added.

5g of pyridine were dissolved in distilled water and diluted to 1000mL.

4.2 standard titration solution of sodium hydroxide [Ba (NaOH) = 0.1mol/L].

According to GB/T 601 Preparation and calibration.

4.3 5g/L of phenolphthalein indicator.

0.5g of phenolphthalein is dissolved in 95% ethanol, and diluted to 100mL.

5 Instruments

5.1 plug Erlenmeyer flask. capacity 250mL.

5.2 Erlenmeyer flask. capacity 250mL.

5.3 Pipette. Capacity 50mL, 100mL.

5.4 Buret. capacity 25mL.

5.5 weighing bottle, dryer.

5.6 Analytical balance. accuracy 0.0002g.

5.7 thermostatic oven. to maintain the drying temperature 105 °C ± 3 °C.

5.8 mechanical oscillator.

5.9 Glass filter crucible. Capacity 30mL ~ 50mL, pore diameter is 40µm ~ 80µm.

6 Sample preparation