Avaliação da qualidade de esmaltes de unha: identificação e validação do método analítico para doseamento do formaldeído e determinação dos parâmetros físico- químicos.

Abstract

The nail polish industry has experienced a sudden growth in past years, as numerous new brands, some of them having questionable quality and formulation problems that could be visually detected. As such, this work’s objective was to identify and validating the analytical method for further dosage of the nail polish formaldehyde, and also to determine their physicochemical parameters. The nail polish established as standard was Revlon®, considered to be a reference item (P1 - red shades; P2 - light shades), and the remaining samples were composed by bottles of nail polish of unknown quality, denoted A1, A2, and A3 (red shades), and A4, A5, and A6 (light shades). Two methodologies were used to identify and quantify the percentage of formaldehyde in the nail polish: the identification suggested by the Quality Control Guidelines of cosmetics which was validated according to the criteria established by the resolution RE 899/2003, and the NIOSH standard method modified by Gasparini. A macroscopic analysis and physicochemical tests were performed in the nail polish samples in order to determine their characteristics in comparison to the standard reference: aspect, color, viscosity, centrifugation, drying time, spreadability, pH and density. The ANVISA method identified the free formaldehyde qualitatively; however, for quantification, the methodology was validated, and showed itself as a specific, linear, precise, exact and robust. The standard model NIOSH, modified by Gasparini, did not allow for the identification or quantification of formaldehyde in nail polish samples, due to the fact that these were linked to the arylsulfonamide resin. The nail polishes that were evaluated presented concentrations of formaldehyde between 0,07% and 0,22%, conforming with current legislation. Their labels, however, did not display all information required by the same resolution. The physicochemical parameters of drying time (7 to 13 minutes), spreadability (from 1200 to 4200 mm2), and viscosity (from 500 to 4100 cP), displayed the largest variation between the tested samples and the reference standards, as opposed to the pH (from 3 to 4) and density (≈ 1) values, which were very similar. These results illustrated the quality of the reference nail polishes and confirmed the absence of formaldehyde in some samples. Nevertheless, the labels did not contain all information previously required by the resolution.