A Novel Method for Titanium Dioxide Quantification in Cosmetic Products via Borate Fusion by Flame Atomic Absorption Spectroscopy

Abstract

A new method for extraction of titanium dioxide (TiO2) from cosmetic matrices using borate salts for its quantification by flame atomic absorption spectroscopy (FAAS) was developed and validated. Following International Commission for Harmonization (ICH) and the United States Pharmacopeial Convention (USP) guidelines, the parameters of the method considered in this study were specificity, linearity, sensitivity, precision, and accuracy. In addition, critical factors of the method were assessed using a Youden–Steiner model. The method was able to differentiate the titanium signal from matrix and background signals, for which it is considered specific. The method is also linear for all cosmetic matrices and the raw material in the range 20–80 ppm with LOD and LOQ around 2 ppm and 7 ppm, respectively. Repeatability and intermediate precision were below 5.0%RSD, and Global Reproducibility was below 8.0% RSD. A digestion step free of HF or strong oxidizers makes this method a safer and easily transferable alternative to classical methods for quality control. It is thus a convenient tool for routine analysis of cosmetic products that need to comply with current regulations to ensure the safety of consumers and to guarantee batch-to-batch quality.