[Validation of a method for discrimination of formaldehyde processing in textile products]

It is important to investigate a cause of formaldehyde contamination exceeding a regulation limit value in a textile product. If formaldehyde was released from a textile product itself by treatment or processing with formaldehyde, an administrative guidance is given to a manufacture. On the other hand, when the formaldehyde migrated from other textile products or a furniture stand during displaying, an improvement instruction is performed to the store. Iwama et al. [Ann. Rep. Nagoya City Public Res. Inst., 42, 11-16 (1996)] developed a method for distinguishing fabric processing and migration by additional hydrolytic extraction using hydrochloric acid solution. This study was to confirm the reliability and stability of the method for knowing formaldehyde processing on textiles. Five laboratories evaluated three samples: unprocessed textile, processed textile and unprocessed but formaldehyde-migrated textile. For a processed textile sample, amounts of formaldehyde increased by additional extractions with acidic solution, so all laboratories judged that the sample had been treated with formaldehyde. In the cases of the other two samples, such increases were not observed in the extracts using acidic solution. All laboratories reported that these samples were not processed using formaldehyde but had absorbed a different level of formaldehyde by migration. In a series of experiments, the judgement about the existence of formaldehyde processing or migration is comparatively consistent among all laboratories. This validation study concluded that the distinguishing method adopting additional extractions with acidic solution is useful to find formaldehyde processing of textile, and to deal with processing and migration separately as a cause of formaldehyde contamination.