Immunological analytical techniques for cosmetics quality control and process monitoring

Cosmetics analysis represents a rapidly expanding field of analytical chemistry as new cosmetic formulations are increasingly in demand on the market and the ingredients required for their production are constantly evolving. Each country applies strict legislation regarding substances in the final product that must be prohibited or regulated. To verify the compliance of cosmetics with current regulations, official analytical methods are available to reveal and quantitatively determine the analytes of interest. However, since ingredients, and the lists of regulated/prohibited substances, rapidly change, dedicated analytical methods must be developed ad hoc to fulfill the new requirements. Research focuses on finding innovative techniques that allow a rapid, inexpensive, and sensitive detection of the target analytes in cosmetics. Among the different methods proposed, immunological techniques are gaining interest, as they make it possible to carry out low-cost analyses on raw materials and finished products in a relatively short time. Indeed, immunoassays are based on the specific and selective antibody/antigen reaction, and they have been extensively applied for clinical diagnostic, alimentary quality control and environmental security purposes, and even for routine analysis. Since the complexity and variability of the matrices, as well as the great variety of compounds present in cosmetics, are analogous with those from food sources, immunological methods could also be applied successfully in this field. Indeed, this would provide a valid approach for the monitoring of industrial production chains even in developing countries, which are currently the greatest producers of cosmetics and the major exporters of raw materials. This review aims to highlight the immunological techniques proposed for cosmetics analysis, focusing on the detection of prohibited/regulated compounds, bacteria and toxins, and allergenic substances, and the identification of counterfeits.