Possibilities of Total Reflection X-ray Fluorescence spectrometry (TXRF) to analyse cosmetics samples

Abstract

Nowadays, cosmetics have evolved a lot and they are produced industrially. To avoid adverse effects on health, it is important to establish the elemental composition of these types of samples. For this reason it is interesting to have fast, cheap, respectful with the environment, with an appropriate accuracy and precision analytical methodologies. Nowadays, analytical methodologies used for the analysis of these types of samples are based on a wet microwave digestion process and its subsequent analysis by Inductively-coupled Plasma Emission Spectrometry (ICP-OES) or Inductively-coupled plasma mass spectrometry (ICP -MS). Despite the fact that these methods have an appropriate sensitivity, their sample treatment involves an important consumption of reagents and time. In view of this problem, in this research project, we have evaluated the possibilities of Total Reflection X-ray Fluorescence spectrometry (TXRF) for the determination of metals and metalloids in different types of cosmetics (lipsticks, eye shadow and creams). In order to obtain the best conditions of work to carry out the analysis of the target samples by TXRF, different experimental parameters regarding sample preparation and measurement conditions were evaluated. Once established the optimal conditions, analytical detection limits, accuracy and precision of the results obtained in the determination of analytes were studied, in order to assess the potential of the methods. Finally, the developed methodologies have been applied to the analysis of cosmetic samples and the results have been compared with those obtained by ICP-OES and ICP-MS. Results show that the TXRF technique can be a complementary alternative or at least a complementary technique to the more commonly used in this type of analysis. In general, the detection limits and the quality of the results are adequate. In addition, there are certain additional benefits such as the multielemental and microanalytical ability, a simple sample preparation, does not need an external calibration as quantification process and also presents a high performance and low cost for analysis