Determination of formaldehyde content in leather: EN ISO 17226 standard. Influence of the agitation method used in the initial phase of formaldehyde extraction

Abstract

Given the carcinogenic character of formaldehyde, it should be reliably determined in any substrate. The EN ISO 17226 Standard is the Official Method to quantify formaldehyde in leather. However, some misunderstandings may arise from the practical conditions given by the Standard for the extraction of formaldehyde. Two agitation methods (magnetic agitation and reciprocal linear agitation), which fulfill the conditions of the Standard, have been used for the extraction of formaldehyde in twenty two samples of wet-blue split leather treated with resins synthesized with formaldehyde and with/without the addition of vegetable compounds. The agitation method influences the formaldehyde content and differences between the agitation methods depend on the formaldehyde resins and vegetable compounds applied. Magnetic agitation leads to formaldehyde contents that are 26% greater than those obtained when the reciprocal linear agitation method is used. Major brands specify allowable limits for formaldehyde content, which depend on the user (adult or babies) and whether the article is in direct contact with the skin. A high percentage of disagreement (33.3%) has been observed between the agitation methods in fulfilling the allowable limits. One-Third of the formaldehyde content results that fulfilled the allowable limits with the reciprocal linear agitation method failed when the magnetic method was applied. The situation urges the clarification of the shaking method in the EN ISO 17226 Standard to avoid the high level of contradictory results between methods that meet the agitation conditions of the Standard.