Azo Dyes that Can Release Harmful Aromatic Amines

Under specified conditions, the sample is placed in a citrate-sodium hydroxide buffer solution and reduced and cleaved with sodium hydrosulfite to release any potentially present aromatic amines. The aromatic amines are extracted into tert-butyl methyl ether using a diatomite column, concentrated, and then diluted to volume with a suitable solvent. Chromatographic methods are used to detect the aromatic amines. If any aromatic amine is detected, confirmation must be performed using one or more additional chromatographic methods.

Formaldehyde Content

The sample is treated using methods such as water extraction, vapor absorption, or high-performance liquid chromatography (HPLC), and the formaldehyde content is calculated by comparing the results to a standard formaldehyde calibration curve.

pH Value

At room temperature, the pH of the aqueous extract of the textile is measured using a pH meter equipped with a glass electrode.

Soluble Matter

The sample is extracted with dichloromethane using a Soxhlet extractor. After evaporation of the solvent, the residue is weighed. The dichloromethane soluble content is calculated as the percentage of the residue mass relative to the dry mass of the sample after extraction.