Fluorine in eye shadow: Development of method using high-resolution continuum source graphite furnace molecular absorption spectrometry via calcium mono-fluoride with direct solid sample introduction

Eye shadows are cosmetics of different colors applied in the periocular area, composed by calcium carbonate, kaolin, titanium dioxide, zinc oxide, pigments, among others. In this study a method has been developed to evaluate the fluorine content in eye shadow samples using high-resolution continuum source graphite furnace molecular absorption spectrometry and direct solid sample analysis with calibration against aqueous standard solutions. The molecular absorption was measured using only the center pixel at 606.045 nm and applying gas flow in the vaporization step. The diatomic molecule CaF was generated by the addition of 100 μg Ca (as Ca(NO3)2·4H2O) as the molecule-forming reagent using a pyrolysis temperature of 1000 °C and a vaporization temperature of 2400 °C. The characteristic mass and limit of detection were 0.68 ng and 2 mg kg− 1, respectively. The accuracy of the method was confirmed using two certified reference materials and by comparison with solubilization of the samples using tetramethylammonium hydroxide. Seven eye shadow samples from China, Brazil and France were analyzed to confirm the applicability of the method to real samples; the concentration of fluorine was found between 0.8 and 2.7 g kg− 1, however there is no legislation to monitor the maximum levels of fluorine in this cosmetic.