Identification and quantification of free formaldehyde in hair straightening creams

Abstract

Formaldehyde is a chemical compound that is widely used in hair straightening products. There have been numerous reports of health problems caused by the use of this product. ANVISA (National Health
Surveillance Agency) has established a maximum level of 0.2% formaldehyde in hair products used only as a preservative, but this limit is often exceeded. In this study, qualitative, semiquantitative and quantitative
analyses were performed for formaldehyde in hair straightening samples collected from a beauty salon in the north zone of Porto Alegre, RS. The samples were subjected to the Schiff reagent for qualitative and 
semiquantitative analysis. The appearance of a pink color indicated the presence of formaldehyde. The quantitative analysis of the samples was performed by back titration. All samples tested positive for the presence of aldehydes; the semiquantitative analysis revealed levels above 0.5% (m/m) for all samples. The quantitative analysis indicated levels between 2.24-9.61% (m/m). The values found in this study were corroborated by values found in the literature. The values found exceed the limits set by ANVISA for hair products, which can lead to various health problems, including death.