Desenvolvimento de método para a determinação de halogênios e enxofre em maquiagens utilizadas na região dos olhos

Abstract

In this study, an analytical method for halogens (Br, Cl, F e I) and sulfur (S) determination in eyelash mascara and liquid eyeliner was developed. Microwave induced combustion (MIC) was evaluated as sample preparation method and ion chromatography with conductivity detection coupled to mass spectrometry (IC-CD-MS) as determination technique. Using the selected conditions (500 mg as sample mass, 50 mmol L-1 of NH4OH as absorbing solution and 5 min as reflux step), the recoveries for halogens and sulfur using recovery tests with reference solutions ranged from 90 to 109%. Certified reference materials (CRMs) were also digested mixed with the sample as recovery tests and no significant difference was observed between the results obtained and the added certified values - recoveries ranging from 90 to 100%. The proposed analytical method presents adequate accuracy, precision (repeatability with relative standard deviations – RSDs – less 10%) and suitable limits of detection (LODs): 1 mg kg−1 for Br, 10 mg kg−1 for Cl, 3 mg kg−1 for F, 0.1 mg kg−1for I and 9 mg kg−1 for S. It is important to emphasize this is the first study that combines MIC with IC CD-MS for halogens and sulfur determination in semi-solid cosmetics - eyelash mascara and liquid eyeliner - in a single chromatographic run, with several advantages such as low residue generation, minimized reagents consumption and high analytical frequency. The concentration of the elements Br (91 mg kg-1), Cl (35 to 9764 mg kg-1), F (15 to 1132 mg kg-1), I (0.4 to 40 mg kg-1) and S (30 to 710 mg kg-1) varied in a wide range when the method was applied for the analysis of eyelash mascaras and liquid eyeliners of different origins, colors and brands.