The study was conducted by an interdisciplinary team of researchers from the SOLARIS National Synchrotron Radiation Centre, AGH University of Krakow, the Institute of Physics of the Jagiellonian University, and an industrial partner, Inglot Sp. z o.o. The aim of this work was to develop a rapid and sensitive method for the determination of trace amounts of lead in raw materials with potential cosmetic applications. The feasibility of using energy-dispersive X-ray fluorescence excited by monochromatic synchrotron radiation (SR-XRF) for the quantitative analysis of samples with complex and unknown matrices was evaluated. The use of synchrotron radiation enabled the achievement of very low detection limits with minimal sample preparation and short measurement times, and the results were validated using the ICP-OES method.
Cosmetic products play a significant role in human life, and their importance continues to increase alongside economic development and improved accessibility for various social groups. However, the growing number of consumers is accompanied by increasing concerns regarding cosmetic safety, particularly with respect to the presence of heavy metals. In the European Union, cosmetic products are regulated under Regulation (EC) No. 1223/2009, according to which lead and its compounds are listed as prohibited substances. Due to natural processes and the ubiquitous presence of ultra-low concentrations of elements in the environment, achieving their complete absence is not feasible, which necessitates the use of reliable and sensitive analytical methods enabling their control at trace levels.
Despite the existence of national recommendations concerning permissible heavy metal contents in cosmetics, harmonised international standards are still lacking. For example, in the United States and Canada a limit of 10 μg/g of lead is recommended, while in Germany the recommended limit is 5 μg/g. Heavy metals, including lead, may enter the human body via oral, inhalation or dermal routes, leading to bioaccumulation and serious adverse health effects, such as DNA damage, disruption of enzymatic activity, or abnormalities in calcium metabolism. Particular attention is given to products applied in the vicinity of the mouth and eyes, due to the risk of ingestion and the increased permeability of the thin skin in these areas.
Read more on the SOLARIS website
Image: Samples of cosmetic raw materials in tablet form just before XRF analysis on the POLYX beamline