(1) China Standard (GB/T 7573-2009)

Weigh 3 samples of 2±0.05g each, cut them into 5×5 mm pieces, place them in a flask containing 100ml of distilled water. Shake the flask to ensure the samples are fully wetted. Place the flask on a shaker and oscillate for 2 hours±5 minutes. Then, directly measure the pH of the water extract (without fabric) at room temperature using a pH meter. Conduct 3 tests per sample, and take the average of the second and third test results as the final result, rounded to 0.1.

(2) EU Standard (EN 1413-1998)

Weigh 3 samples of 2±0.05g each, cut them into 5×5 mm pieces, and place them in a flask containing 100ml of potassium chloride solution (0.1mol/L) or 100ml of distilled water. Shake the flask to ensure the samples are fully wetted. Place the flask on a shaker for 2 hours. Then, directly measure the pH of the water extract (without fabric) at room temperature using a pH meter. Conduct 3 trials per sample, and take the average of the second and third trial results as the final outcome, rounded to 0.1.

(3) Japanese Industrial Standard (JIS L 1096-1999)

Weigh 5±0.1g of the sample, cut it into 1×1mm pieces, boil 50ml of distilled water for 2 minutes, then place the sample in the flask, swirl to ensure complete wetting, let it stand at room temperature for 30 minutes, remove the sample, and directly measure the pH of the water extract with a pH meter when the temperature reaches 25±2℃, with an accuracy of 0.1.

(4) American Standards (AATCC 81-2001)

Weigh 10±0.1g of the sample, cut it into small pieces, boil and maintain it in 250ml of distilled water for 10 minutes. Place the sample in the flask, shake the flask to ensure the sample is fully soaked, then continue boiling for another 10 minutes. After cooling to room temperature, remove the sample, and directly measure the pH value of the water extract using a pH meter, accurate to 0.01.